Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-lguest

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-lguest: (45 commits)
  Use "struct boot_params" in example launcher
  Loading bzImage directly.
  Revert lguest magic and use hook in head.S
  Update lguest documentation to reflect the new virtual block device name.
  generalize lgread_u32/lgwrite_u32.
  Example launcher handle guests not being ready for input
  Update example launcher for virtio
  Lguest support for Virtio
  Remove old lguest I/O infrrasructure.
  Remove old lguest bus and drivers.
  Virtio helper routines for a descriptor ringbuffer implementation
  Module autoprobing support for virtio drivers.
  Virtio console driver
  Block driver using virtio.
  Net driver using virtio
  Virtio interface
  Boot with virtual == physical to get closer to native Linux.
  Allow guest to specify syscall vector to use.
  Rename "cr3" to "gpgdir" to avoid x86-specific naming.
  Pagetables to use normal kernel types
  ...

36 files changed, 2911 insertions, 4264 deletions

diff --git a/drivers/Kconfig b/drivers/Kconfig
index 34f40ea..f4076d9 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -94,5 +94,5 @@ source "drivers/kvm/Kconfig"
 
 source "drivers/uio/Kconfig"
 
-source "drivers/lguest/Kconfig"
+source "drivers/virtio/Kconfig"
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index cfe38ff..560496b 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -91,3 +91,4 @@ obj-$(CONFIG_HID)		+= hid/
 obj-$(CONFIG_PPC_PS3)		+= ps3/
 obj-$(CONFIG_OF)		+= of/
 obj-$(CONFIG_SSB)		+= ssb/
+obj-$(CONFIG_VIRTIO)		+= virtio/
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index ce4b1e4..4d0119e 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -425,4 +425,10 @@ config XEN_BLKDEV_FRONTEND
 	  block device driver.  It communicates with a back-end driver
 	  in another domain which drives the actual block device.
 
+config VIRTIO_BLK
+	tristate "Virtio block driver (EXPERIMENTAL)"
+	depends on EXPERIMENTAL && VIRTIO
+	---help---
+	  This is the virtual block driver for lguest.  Say Y or M.
+
 endif # BLK_DEV
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 014e721..7691505 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -25,10 +25,10 @@ obj-$(CONFIG_SUNVDC)		+= sunvdc.o
 obj-$(CONFIG_BLK_DEV_UMEM)	+= umem.o
 obj-$(CONFIG_BLK_DEV_NBD)	+= nbd.o
 obj-$(CONFIG_BLK_DEV_CRYPTOLOOP) += cryptoloop.o
+obj-$(CONFIG_VIRTIO_BLK)	+= virtio_blk.o
 
 obj-$(CONFIG_VIODASD)		+= viodasd.o
 obj-$(CONFIG_BLK_DEV_SX8)	+= sx8.o
 obj-$(CONFIG_BLK_DEV_UB)	+= ub.o
 
 obj-$(CONFIG_XEN_BLKDEV_FRONTEND)	+= xen-blkfront.o
-obj-$(CONFIG_LGUEST_BLOCK)	+= lguest_blk.o
diff --git a/drivers/block/lguest_blk.c b/drivers/block/lguest_blk.c
deleted file mode 100644
index fa8e423..0000000
--- a/drivers/block/lguest_blk.c
+++ /dev/null
@@ -1,421 +0,0 @@
-/*D:400
- * The Guest block driver
- *
- * This is a simple block driver, which appears as /dev/lgba, lgbb, lgbc etc.
- * The mechanism is simple: we place the information about the request in the
- * device page, then use SEND_DMA (containing the data for a write, or an empty
- * "ping" DMA for a read).
- :*/
-/* Copyright 2006 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- */
-//#define DEBUG
-#include <linux/init.h>
-#include <linux/types.h>
-#include <linux/blkdev.h>
-#include <linux/interrupt.h>
-#include <linux/lguest_bus.h>
-
-static char next_block_index = 'a';
-
-/*D:420 Here is the structure which holds all the information we need about
- * each Guest block device.
- *
- * I'm sure at this stage, you're wondering "hey, where was the adventure I was
- * promised?" and thinking "Rusty sucks, I shall say nasty things about him on
- * my blog".  I think Real adventures have boring bits, too, and you're in the
- * middle of one.  But it gets better.  Just not quite yet. */
-struct blockdev
-{
-	/* The block queue infrastructure wants a spinlock: it is held while it
-	 * calls our block request function.  We grab it in our interrupt
-	 * handler so the responses don't mess with new requests. */
-	spinlock_t lock;
-
-	/* The disk structure registered with kernel. */
-	struct gendisk *disk;
-
-	/* The major device number for this disk, and the interrupt.  We only
-	 * really keep them here for completeness; we'd need them if we
-	 * supported device unplugging. */
-	int major;
-	int irq;
-
-	/* The physical address of this device's memory page */
-	unsigned long phys_addr;
-	/* The mapped memory page for convenient acces. */
-	struct lguest_block_page *lb_page;
-
-	/* We only have a single request outstanding at a time: this is it. */
-	struct lguest_dma dma;
-	struct request *req;
-};
-
-/*D:495 We originally used end_request() throughout the driver, but it turns
- * out that end_request() is deprecated, and doesn't actually end the request
- * (which seems like a good reason to deprecate it!).  It simply ends the first
- * bio.  So if we had 3 bios in a "struct request" we would do all 3,
- * end_request(), do 2, end_request(), do 1 and end_request(): twice as much
- * work as we needed to do.
- *
- * This reinforced to me that I do not understand the block layer.
- *
- * Nonetheless, Jens Axboe gave me this nice helper to end all chunks of a
- * request.  This improved disk speed by 130%. */
-static void end_entire_request(struct request *req, int uptodate)
-{
-	if (end_that_request_first(req, uptodate, req->hard_nr_sectors))
-		BUG();
-	add_disk_randomness(req->rq_disk);
-	blkdev_dequeue_request(req);
-	end_that_request_last(req, uptodate);
-}
-
-/* I'm told there are only two stories in the world worth telling: love and
- * hate.  So there used to be a love scene here like this:
- *
- *  Launcher:	We could make beautiful I/O together, you and I.
- *  Guest:	My, that's a big disk!
- *
- * Unfortunately, it was just too raunchy for our otherwise-gentle tale. */
-
-/*D:490 This is the interrupt handler, called when a block read or write has
- * been completed for us. */
-static irqreturn_t lgb_irq(int irq, void *_bd)
-{
-	/* We handed our "struct blockdev" as the argument to request_irq(), so
-	 * it is passed through to us here.  This tells us which device we're
-	 * dealing with in case we have more than one. */
-	struct blockdev *bd = _bd;
-	unsigned long flags;
-
-	/* We weren't doing anything?  Strange, but could happen if we shared
-	 * interrupts (we don't!). */
-	if (!bd->req) {
-		pr_debug("No work!\n");
-		return IRQ_NONE;
-	}
-
-	/* Not done yet?  That's equally strange. */
-	if (!bd->lb_page->result) {
-		pr_debug("No result!\n");
-		return IRQ_NONE;
-	}
-
-	/* We have to grab the lock before ending the request. */
-	spin_lock_irqsave(&bd->lock, flags);
-	/* "result" is 1 for success, 2 for failure: end_entire_request() wants
-	 * to know whether this succeeded or not. */
-	end_entire_request(bd->req, bd->lb_page->result == 1);
-	/* Clear out request, it's done. */
-	bd->req = NULL;
-	/* Reset incoming DMA for next time. */
-	bd->dma.used_len = 0;
-	/* Ready for more reads or writes */
-	blk_start_queue(bd->disk->queue);
-	spin_unlock_irqrestore(&bd->lock, flags);
-
-	/* The interrupt was for us, we dealt with it. */
-	return IRQ_HANDLED;
-}
-
-/*D:480 The block layer's "struct request" contains a number of "struct bio"s,
- * each of which contains "struct bio_vec"s, each of which contains a page, an
- * offset and a length.
- *
- * Fortunately there are iterators to help us walk through the "struct
- * request".  Even more fortunately, there were plenty of places to steal the
- * code from.  We pack the "struct request" into our "struct lguest_dma" and
- * return the total length. */
-static unsigned int req_to_dma(struct request *req, struct lguest_dma *dma)
-{
-	unsigned int i = 0, len = 0;
-	struct req_iterator iter;
-	struct bio_vec *bvec;
-
-	rq_for_each_segment(bvec, req, iter) {
-		/* We told the block layer not to give us too many. */
-		BUG_ON(i == LGUEST_MAX_DMA_SECTIONS);
-		/* If we had a zero-length segment, it would look like
-		 * the end of the data referred to by the "struct
-		 * lguest_dma", so make sure that doesn't happen. */
-		BUG_ON(!bvec->bv_len);
-		/* Convert page & offset to a physical address */
-		dma->addr[i] = page_to_phys(bvec->bv_page)
-			+ bvec->bv_offset;
-		dma->len[i] = bvec->bv_len;
-		len += bvec->bv_len;
-		i++;
-	}
-	/* If the array isn't full, we mark the end with a 0 length */
-	if (i < LGUEST_MAX_DMA_SECTIONS)
-		dma->len[i] = 0;
-	return len;
-}
-
-/* This creates an empty DMA, useful for prodding the Host without sending data
- * (ie. when we want to do a read) */
-static void empty_dma(struct lguest_dma *dma)
-{
-	dma->len[0] = 0;
-}
-
-/*D:470 Setting up a request is fairly easy: */
-static void setup_req(struct blockdev *bd,
-		      int type, struct request *req, struct lguest_dma *dma)
-{
-	/* The type is 1 (write) or 0 (read). */
-	bd->lb_page->type = type;
-	/* The sector on disk where the read or write starts. */
-	bd->lb_page->sector = req->sector;
-	/* The result is initialized to 0 (unfinished). */
-	bd->lb_page->result = 0;
-	/* The current request (so we can end it in the interrupt handler). */
-	bd->req = req;
-	/* The number of bytes: returned as a side-effect of req_to_dma(),
-	 * which packs the block layer's "struct request" into our "struct
-	 * lguest_dma" */
-	bd->lb_page->bytes = req_to_dma(req, dma);
-}
-
-/*D:450 Write is pretty straightforward: we pack the request into a "struct
- * lguest_dma", then use SEND_DMA to send the request. */
-static void do_write(struct blockdev *bd, struct request *req)
-{
-	struct lguest_dma send;
-
-	pr_debug("lgb: WRITE sector %li\n", (long)req->sector);
-	setup_req(bd, 1, req, &send);
-
-	lguest_send_dma(bd->phys_addr, &send);
-}
-
-/* Read is similar to write, except we pack the request into our receive
- * "struct lguest_dma" and send through an empty DMA just to tell the Host that
- * there's a request pending. */
-static void do_read(struct blockdev *bd, struct request *req)
-{
-	struct lguest_dma ping;
-
-	pr_debug("lgb: READ sector %li\n", (long)req->sector);
-	setup_req(bd, 0, req, &bd->dma);
-
-	empty_dma(&ping);
-	lguest_send_dma(bd->phys_addr, &ping);
-}
-
-/*D:440 This where requests come in: we get handed the request queue and are
- * expected to pull a "struct request" off it until we've finished them or
- * we're waiting for a reply: */
-static void do_lgb_request(struct request_queue *q)
-{
-	struct blockdev *bd;
-	struct request *req;
-
-again:
-	/* This sometimes returns NULL even on the very first time around.  I
-	 * wonder if it's something to do with letting elves handle the request
-	 * queue... */
-	req = elv_next_request(q);
-	if (!req)
-		return;
-
-	/* We attached the struct blockdev to the disk: get it back */
-	bd = req->rq_disk->private_data;
-	/* Sometimes we get repeated requests after blk_stop_queue(), but we
-	 * can only handle one at a time. */
-	if (bd->req)
-		return;
-
-	/* We only do reads and writes: no tricky business! */
-	if (!blk_fs_request(req)) {
-		pr_debug("Got non-command 0x%08x\n", req->cmd_type);
-		req->errors++;
-		end_entire_request(req, 0);
-		goto again;
-	}
-
-	if (rq_data_dir(req) == WRITE)
-		do_write(bd, req);
-	else
-		do_read(bd, req);
-
-	/* We've put out the request, so stop any more coming in until we get
-	 * an interrupt, which takes us to lgb_irq() to re-enable the queue. */
-	blk_stop_queue(q);
-}
-
-/*D:430 This is the "struct block_device_operations" we attach to the disk at
- * the end of lguestblk_probe().  It doesn't seem to want much. */
-static struct block_device_operations lguestblk_fops = {
-	.owner = THIS_MODULE,
-};
-
-/*D:425 Setting up a disk device seems to involve a lot of code.  I'm not sure
- * quite why.  I do know that the IDE code sent two or three of the maintainers
- * insane, perhaps this is the fringe of the same disease?
- *
- * As in the console code, the probe function gets handed the generic
- * lguest_device from lguest_bus.c: */
-static int lguestblk_probe(struct lguest_device *lgdev)
-{
-	struct blockdev *bd;
-	int err;
-	int irqflags = IRQF_SHARED;
-
-	/* First we allocate our own "struct blockdev" and initialize the easy
-	 * fields. */
-	bd = kmalloc(sizeof(*bd), GFP_KERNEL);
-	if (!bd)
-		return -ENOMEM;
-
-	spin_lock_init(&bd->lock);
-	bd->irq = lgdev_irq(lgdev);
-	bd->req = NULL;
-	bd->dma.used_len = 0;
-	bd->dma.len[0] = 0;
-	/* The descriptor in the lguest_devices array provided by the Host
-	 * gives the Guest the physical page number of the device's page. */
-	bd->phys_addr = (lguest_devices[lgdev->index].pfn << PAGE_SHIFT);
-
-	/* We use lguest_map() to get a pointer to the device page */
-	bd->lb_page = lguest_map(bd->phys_addr, 1);
-	if (!bd->lb_page) {
-		err = -ENOMEM;
-		goto out_free_bd;
-	}
-
-	/* We need a major device number: 0 means "assign one dynamically". */
-	bd->major = register_blkdev(0, "lguestblk");
-	if (bd->major < 0) {
-		err = bd->major;
-		goto out_unmap;
-	}
-
-	/* This allocates a "struct gendisk" where we pack all the information
-	 * about the disk which the rest of Linux sees.  The argument is the
-	 * number of minor devices desired: we need one minor for the main
-	 * disk, and one for each partition.  Of course, we can't possibly know
-	 * how many partitions are on the disk (add_disk does that).
-	 */
-	bd->disk = alloc_disk(16);
-	if (!bd->disk) {
-		err = -ENOMEM;
-		goto out_unregister_blkdev;
-	}
-
-	/* Every disk needs a queue for requests to come in: we set up the
-	 * queue with a callback function (the core of our driver) and the lock
-	 * to use. */
-	bd->disk->queue = blk_init_queue(do_lgb_request, &bd->lock);
-	if (!bd->disk->queue) {
-		err = -ENOMEM;
-		goto out_put_disk;
-	}
-
-	/* We can only handle a certain number of pointers in our SEND_DMA
-	 * call, so we set that with blk_queue_max_hw_segments().  This is not
-	 * to be confused with blk_queue_max_phys_segments() of course!  I
-	 * know, who could possibly confuse the two?
-	 *
-	 * Well, it's simple to tell them apart: this one seems to work and the
-	 * other one didn't. */
-	blk_queue_max_hw_segments(bd->disk->queue, LGUEST_MAX_DMA_SECTIONS);
-
-	/* Due to technical limitations of our Host (and simple coding) we
-	 * can't have a single buffer which crosses a page boundary.  Tell it
-	 * here.  This means that our maximum request size is 16
-	 * (LGUEST_MAX_DMA_SECTIONS) pages. */
-	blk_queue_segment_boundary(bd->disk->queue, PAGE_SIZE-1);
-
-	/* We name our disk: this becomes the device name when udev does its
-	 * magic thing and creates the device node, such as /dev/lgba.
-	 * next_block_index is a global which starts at 'a'.  Unfortunately
-	 * this simple increment logic means that the 27th disk will be called
-	 * "/dev/lgb{".  In that case, I recommend having at least 29 disks, so
-	 * your /dev directory will be balanced. */
-	sprintf(bd->disk->disk_name, "lgb%c", next_block_index++);
-
-	/* We look to the device descriptor again to see if this device's
-	 * interrupts are expected to be random.  If they are, we tell the irq
-	 * subsystem.  At the moment this bit is always set. */
-	if (lguest_devices[lgdev->index].features & LGUEST_DEVICE_F_RANDOMNESS)
-		irqflags |= IRQF_SAMPLE_RANDOM;
-
-	/* Now we have the name and irqflags, we can request the interrupt; we
-	 * give it the "struct blockdev" we have set up to pass to lgb_irq()
-	 * when there is an interrupt. */
-	err = request_irq(bd->irq, lgb_irq, irqflags, bd->disk->disk_name, bd);
-	if (err)
-		goto out_cleanup_queue;
-
-	/* We bind our one-entry DMA pool to the key for this block device so
-	 * the Host can reply to our requests.  The key is equal to the
-	 * physical address of the device's page, which is conveniently
-	 * unique. */
-	err = lguest_bind_dma(bd->phys_addr, &bd->dma, 1, bd->irq);
-	if (err)
-		goto out_free_irq;
-
-	/* We finish our disk initialization and add the disk to the system. */
-	bd->disk->major = bd->major;
-	bd->disk->first_minor = 0;
-	bd->disk->private_data = bd;
-	bd->disk->fops = &lguestblk_fops;
-	/* This is initialized to the disk size by the Launcher. */
-	set_capacity(bd->disk, bd->lb_page->num_sectors);
-	add_disk(bd->disk);
-
-	printk(KERN_INFO "%s: device %i at major %d\n",
-	       bd->disk->disk_name, lgdev->index, bd->major);
-
-	/* We don't need to keep the "struct blockdev" around, but if we ever
-	 * implemented device removal, we'd need this. */
-	lgdev->private = bd;
-	return 0;
-
-out_free_irq:
-	free_irq(bd->irq, bd);
-out_cleanup_queue:
-	blk_cleanup_queue(bd->disk->queue);
-out_put_disk:
-	put_disk(bd->disk);
-out_unregister_blkdev:
-	unregister_blkdev(bd->major, "lguestblk");
-out_unmap:
-	lguest_unmap(bd->lb_page);
-out_free_bd:
-	kfree(bd);
-	return err;
-}
-
-/*D:410 The boilerplate code for registering the lguest block driver is just
- * like the console: */
-static struct lguest_driver lguestblk_drv = {
-	.name = "lguestblk",
-	.owner = THIS_MODULE,
-	.device_type = LGUEST_DEVICE_T_BLOCK,
-	.probe = lguestblk_probe,
-};
-
-static __init int lguestblk_init(void)
-{
-	return register_lguest_driver(&lguestblk_drv);
-}
-module_init(lguestblk_init);
-
-MODULE_DESCRIPTION("Lguest block driver");
-MODULE_LICENSE("GPL");
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
new file mode 100644
index 0000000..a901eee
--- /dev/null
+++ b/drivers/block/virtio_blk.c
@@ -0,0 +1,308 @@
+//#define DEBUG
+#include <linux/spinlock.h>
+#include <linux/blkdev.h>
+#include <linux/hdreg.h>
+#include <linux/virtio.h>
+#include <linux/virtio_blk.h>
+#include <linux/virtio_blk.h>
+
+static unsigned char virtblk_index = 'a';
+struct virtio_blk
+{
+	spinlock_t lock;
+
+	struct virtio_device *vdev;
+	struct virtqueue *vq;
+
+	/* The disk structure for the kernel. */
+	struct gendisk *disk;
+
+	/* Request tracking. */
+	struct list_head reqs;
+
+	mempool_t *pool;
+
+	/* Scatterlist: can be too big for stack. */
+	struct scatterlist sg[3+MAX_PHYS_SEGMENTS];
+};
+
+struct virtblk_req
+{
+	struct list_head list;
+	struct request *req;
+	struct virtio_blk_outhdr out_hdr;
+	struct virtio_blk_inhdr in_hdr;
+};
+
+static bool blk_done(struct virtqueue *vq)
+{
+	struct virtio_blk *vblk = vq->vdev->priv;
+	struct virtblk_req *vbr;
+	unsigned int len;
+	unsigned long flags;
+
+	spin_lock_irqsave(&vblk->lock, flags);
+	while ((vbr = vblk->vq->vq_ops->get_buf(vblk->vq, &len)) != NULL) {
+		int uptodate;
+		switch (vbr->in_hdr.status) {
+		case VIRTIO_BLK_S_OK:
+			uptodate = 1;
+			break;
+		case VIRTIO_BLK_S_UNSUPP:
+			uptodate = -ENOTTY;
+			break;
+		default:
+			uptodate = 0;
+			break;
+		}
+
+		end_dequeued_request(vbr->req, uptodate);
+		list_del(&vbr->list);
+		mempool_free(vbr, vblk->pool);
+	}
+	/* In case queue is stopped waiting for more buffers. */
+	blk_start_queue(vblk->disk->queue);
+	spin_unlock_irqrestore(&vblk->lock, flags);
+	return true;
+}
+
+static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
+		   struct request *req)
+{
+	unsigned long num, out, in;
+	struct virtblk_req *vbr;
+
+	vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
+	if (!vbr)
+		/* When another request finishes we'll try again. */
+		return false;
+
+	vbr->req = req;
+	if (blk_fs_request(vbr->req)) {
+		vbr->out_hdr.type = 0;
+		vbr->out_hdr.sector = vbr->req->sector;
+		vbr->out_hdr.ioprio = vbr->req->ioprio;
+	} else if (blk_pc_request(vbr->req)) {
+		vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
+		vbr->out_hdr.sector = 0;
+		vbr->out_hdr.ioprio = vbr->req->ioprio;
+	} else {
+		/* We don't put anything else in the queue. */
+		BUG();
+	}
+
+	if (blk_barrier_rq(vbr->req))
+		vbr->out_hdr.type |= VIRTIO_BLK_T_BARRIER;
+
+	/* We have to zero this, otherwise blk_rq_map_sg gets upset. */
+	memset(vblk->sg, 0, sizeof(vblk->sg));
+	sg_set_buf(&vblk->sg[0], &vbr->out_hdr, sizeof(vbr->out_hdr));
+	num = blk_rq_map_sg(q, vbr->req, vblk->sg+1);
+	sg_set_buf(&vblk->sg[num+1], &vbr->in_hdr, sizeof(vbr->in_hdr));
+
+	if (rq_data_dir(vbr->req) == WRITE) {
+		vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
+		out = 1 + num;
+		in = 1;
+	} else {
+		vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
+		out = 1;
+		in = 1 + num;
+	}
+
+	if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr)) {
+		mempool_free(vbr, vblk->pool);
+		return false;
+	}
+
+	list_add_tail(&vbr->list, &vblk->reqs);
+	return true;
+}
+
+static void do_virtblk_request(struct request_queue *q)
+{
+	struct virtio_blk *vblk = NULL;
+	struct request *req;
+	unsigned int issued = 0;
+
+	while ((req = elv_next_request(q)) != NULL) {
+		vblk = req->rq_disk->private_data;
+		BUG_ON(req->nr_phys_segments > ARRAY_SIZE(vblk->sg));
+
+		/* If this request fails, stop queue and wait for something to
+		   finish to restart it. */
+		if (!do_req(q, vblk, req)) {
+			blk_stop_queue(q);
+			break;
+		}
+		blkdev_dequeue_request(req);
+		issued++;
+	}
+
+	if (issued)
+		vblk->vq->vq_ops->kick(vblk->vq);
+}
+
+static int virtblk_ioctl(struct inode *inode, struct file *filp,
+			 unsigned cmd, unsigned long data)
+{
+	return scsi_cmd_ioctl(filp, inode->i_bdev->bd_disk->queue,
+			      inode->i_bdev->bd_disk, cmd,
+			      (void __user *)data);
+}
+
+static struct block_device_operations virtblk_fops = {
+	.ioctl = virtblk_ioctl,
+	.owner = THIS_MODULE,
+};
+
+static int virtblk_probe(struct virtio_device *vdev)
+{
+	struct virtio_blk *vblk;
+	int err, major;
+	void *token;
+	unsigned int len;
+	u64 cap;
+	u32 v;
+
+	vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
+	if (!vblk) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	INIT_LIST_HEAD(&vblk->reqs);
+	spin_lock_init(&vblk->lock);
+	vblk->vdev = vdev;
+
+	/* We expect one virtqueue, for output. */
+	vblk->vq = vdev->config->find_vq(vdev, blk_done);
+	if (IS_ERR(vblk->vq)) {
+		err = PTR_ERR(vblk->vq);
+		goto out_free_vblk;
+	}
+
+	vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
+	if (!vblk->pool) {
+		err = -ENOMEM;
+		goto out_free_vq;
+	}
+
+	major = register_blkdev(0, "virtblk");
+	if (major < 0) {
+		err = major;
+		goto out_mempool;
+	}
+
+	/* FIXME: How many partitions?  How long is a piece of string? */
+	vblk->disk = alloc_disk(1 << 4);
+	if (!vblk->disk) {
+		err = -ENOMEM;
+		goto out_unregister_blkdev;
+	}
+
+	vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
+	if (!vblk->disk->queue) {
+		err = -ENOMEM;
+		goto out_put_disk;
+	}
+
+	sprintf(vblk->disk->disk_name, "vd%c", virtblk_index++);
+	vblk->disk->major = major;
+	vblk->disk->first_minor = 0;
+	vblk->disk->private_data = vblk;
+	vblk->disk->fops = &virtblk_fops;
+
+	/* If barriers are supported, tell block layer that queue is ordered */
+	token = vdev->config->find(vdev, VIRTIO_CONFIG_BLK_F, &len);
+	if (virtio_use_bit(vdev, token, len, VIRTIO_BLK_F_BARRIER))
+		blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);
+
+	err = virtio_config_val(vdev, VIRTIO_CONFIG_BLK_F_CAPACITY, &cap);
+	if (err) {
+		dev_err(&vdev->dev, "Bad/missing capacity in config\n");
+		goto out_put_disk;
+	}
+
+	/* If capacity is too big, truncate with warning. */
+	if ((sector_t)cap != cap) {
+		dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
+			 (unsigned long long)cap);
+		cap = (sector_t)-1;
+	}
+	set_capacity(vblk->disk, cap);
+
+	err = virtio_config_val(vdev, VIRTIO_CONFIG_BLK_F_SIZE_MAX, &v);
+	if (!err)
+		blk_queue_max_segment_size(vblk->disk->queue, v);
+	else if (err != -ENOENT) {
+		dev_err(&vdev->dev, "Bad SIZE_MAX in config\n");
+		goto out_put_disk;
+	}
+
+	err = virtio_config_val(vdev, VIRTIO_CONFIG_BLK_F_SEG_MAX, &v);
+	if (!err)
+		blk_queue_max_hw_segments(vblk->disk->queue, v);
+	else if (err != -ENOENT) {
+		dev_err(&vdev->dev, "Bad SEG_MAX in config\n");
+		goto out_put_disk;
+	}
+
+	add_disk(vblk->disk);
+	return 0;
+
+out_put_disk:
+	put_disk(vblk->disk);
+out_unregister_blkdev:
+	unregister_blkdev(major, "virtblk");
+out_mempool:
+	mempool_destroy(vblk->pool);
+out_free_vq:
+	vdev->config->del_vq(vblk->vq);
+out_free_vblk:
+	kfree(vblk);
+out:
+	return err;
+}
+
+static void virtblk_remove(struct virtio_device *vdev)
+{
+	struct virtio_blk *vblk = vdev->priv;
+	int major = vblk->disk->major;
+
+	BUG_ON(!list_empty(&vblk->reqs));
+	blk_cleanup_queue(vblk->disk->queue);
+	put_disk(vblk->disk);
+	unregister_blkdev(major, "virtblk");
+	mempool_destroy(vblk->pool);
+	kfree(vblk);
+}
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static struct virtio_driver virtio_blk = {
+	.driver.name =	KBUILD_MODNAME,
+	.driver.owner =	THIS_MODULE,
+	.id_table =	id_table,
+	.probe =	virtblk_probe,
+	.remove =	__devexit_p(virtblk_remove),
+};
+
+static int __init init(void)
+{
+	return register_virtio_driver(&virtio_blk);
+}
+
+static void __exit fini(void)
+{
+	unregister_virtio_driver(&virtio_blk);
+}
+module_init(init);
+module_exit(fini);
+
+MODULE_DEVICE_TABLE(virtio, id_table);
+MODULE_DESCRIPTION("Virtio block driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 6549110..bf18d75 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -613,6 +613,10 @@ config HVC_XEN
 	help
 	  Xen virtual console device driver
 
+config VIRTIO_CONSOLE
+	bool
+	select HVC_DRIVER
+
 config HVCS
 	tristate "IBM Hypervisor Virtual Console Server support"
 	depends on PPC_PSERIES
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index c78ff26..07304d5 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -42,7 +42,6 @@ obj-$(CONFIG_SYNCLINK_GT)	+= synclink_gt.o
 obj-$(CONFIG_N_HDLC)		+= n_hdlc.o
 obj-$(CONFIG_AMIGA_BUILTIN_SERIAL) += amiserial.o
 obj-$(CONFIG_SX)		+= sx.o generic_serial.o
-obj-$(CONFIG_LGUEST_GUEST)	+= hvc_lguest.o
 obj-$(CONFIG_RIO)		+= rio/ generic_serial.o
 obj-$(CONFIG_HVC_CONSOLE)	+= hvc_vio.o hvsi.o
 obj-$(CONFIG_HVC_ISERIES)	+= hvc_iseries.o
@@ -50,6 +49,7 @@ obj-$(CONFIG_HVC_RTAS)		+= hvc_rtas.o
 obj-$(CONFIG_HVC_BEAT)		+= hvc_beat.o
 obj-$(CONFIG_HVC_DRIVER)	+= hvc_console.o
 obj-$(CONFIG_HVC_XEN)		+= hvc_xen.o
+obj-$(CONFIG_VIRTIO_CONSOLE)	+= virtio_console.o
 obj-$(CONFIG_RAW_DRIVER)	+= raw.o
 obj-$(CONFIG_SGI_SNSC)		+= snsc.o snsc_event.o
 obj-$(CONFIG_MSPEC)		+= mspec.o
diff --git a/drivers/char/hvc_lguest.c b/drivers/char/hvc_lguest.c
deleted file mode 100644
index efccb21..0000000
--- a/drivers/char/hvc_lguest.c
+++ /dev/null
@@ -1,177 +0,0 @@
-/*D:300
- * The Guest console driver
- *
- * This is a trivial console driver: we use lguest's DMA mechanism to send
- * bytes out, and register a DMA buffer to receive bytes in.  It is assumed to
- * be present and available from the very beginning of boot.
- *
- * Writing console drivers is one of the few remaining Dark Arts in Linux.
- * Fortunately for us, the path of virtual consoles has been well-trodden by
- * the PowerPC folks, who wrote "hvc_console.c" to generically support any
- * virtual console.  We use that infrastructure which only requires us to write
- * the basic put_chars and get_chars functions and call the right register
- * functions.
- :*/
-
-/*M:002 The console can be flooded: while the Guest is processing input the
- * Host can send more.  Buffering in the Host could alleviate this, but it is a
- * difficult problem in general. :*/
-/* Copyright (C) 2006 Rusty Russell, IBM Corporation
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- */
-#include <linux/err.h>
-#include <linux/init.h>
-#include <linux/lguest_bus.h>
-#include <asm/paravirt.h>
-#include "hvc_console.h"
-
-/*D:340 This is our single console input buffer, with associated "struct
- * lguest_dma" referring to it.  Note the 0-terminated length array, and the
- * use of physical address for the buffer itself. */
-static char inbuf[256];
-static struct lguest_dma cons_input = { .used_len = 0,
-					.addr[0] = __pa(inbuf),
-					.len[0] = sizeof(inbuf),
-					.len[1] = 0 };
-
-/*D:310 The put_chars() callback is pretty straightforward.
- *
- * First we put the pointer and length in a "struct lguest_dma": we only have
- * one pointer, so we set the second length to 0.  Then we use SEND_DMA to send
- * the data to (Host) buffers attached to the console key.  Usually a device's
- * key is a physical address within the device's memory, but because the
- * console device doesn't have any associated physical memory, we use the
- * LGUEST_CONSOLE_DMA_KEY constant (aka 0). */
-static int put_chars(u32 vtermno, const char *buf, int count)
-{
-	struct lguest_dma dma;
-
-	/* FIXME: DMA buffers in a "struct lguest_dma" are not allowed
-	 * to go over page boundaries.  This never seems to happen,
-	 * but if it did we'd need to fix this code. */
-	dma.len[0] = count;
-	dma.len[1] = 0;
-	dma.addr[0] = __pa(buf);
-
-	lguest_send_dma(LGUEST_CONSOLE_DMA_KEY, &dma);
-	/* We're expected to return the amount of data we wrote: all of it. */
-	return count;
-}
-
-/*D:350 get_chars() is the callback from the hvc_console infrastructure when
- * an interrupt is received.
- *
- * Firstly we see if our buffer has been filled: if not, we return.  The rest
- * of the code deals with the fact that the hvc_console() infrastructure only
- * asks us for 16 bytes at a time.  We keep a "cons_offset" variable for
- * partially-read buffers. */
-static int get_chars(u32 vtermno, char *buf, int count)
-{
-	static int cons_offset;
-
-	/* Nothing left to see here... */
-	if (!cons_input.used_len)
-		return 0;
-
-	/* You want more than we have to give?  Well, try wanting less! */
-	if (cons_input.used_len - cons_offset < count)
-		count = cons_input.used_len - cons_offset;
-
-	/* Copy across to their buffer and increment offset. */
-	memcpy(buf, inbuf + cons_offset, count);
-	cons_offset += count;
-
-	/* Finished?  Zero offset, and reset cons_input so Host will use it
-	 * again. */
-	if (cons_offset == cons_input.used_len) {
-		cons_offset = 0;
-		cons_input.used_len = 0;
-	}
-	return count;
-}
-/*:*/
-
-static struct hv_ops lguest_cons = {
-	.get_chars = get_chars,
-	.put_chars = put_chars,
-};
-
-/*D:320 Console drivers are initialized very early so boot messages can go
- * out.  At this stage, the console is output-only.  Our driver checks we're a
- * Guest, and if so hands hvc_instantiate() the console number (0), priority
- * (0), and the struct hv_ops containing the put_chars() function. */
-static int __init cons_init(void)
-{
-	if (strcmp(pv_info.name, "lguest") != 0)
-		return 0;
-
-	return hvc_instantiate(0, 0, &lguest_cons);
-}
-console_initcall(cons_init);
-
-/*D:370 To set up and manage our virtual console, we call hvc_alloc() and
- * stash the result in the private pointer of the "struct lguest_device".
- * Since we never remove the console device we never need this pointer again,
- * but using ->private is considered good form, and you never know who's going
- * to copy your driver.
- *
- * Once the console is set up, we bind our input buffer ready for input. */
-static int lguestcons_probe(struct lguest_device *lgdev)
-{
-	int err;
-
-	/* The first argument of hvc_alloc() is the virtual console number, so
-	 * we use zero.  The second argument is the interrupt number.
-	 *
-	 * The third argument is a "struct hv_ops" containing the put_chars()
-	 * and get_chars() pointers.  The final argument is the output buffer
-	 * size: we use 256 and expect the Host to have room for us to send
-	 * that much. */
-	lgdev->private = hvc_alloc(0, lgdev_irq(lgdev), &lguest_cons, 256);
-	if (IS_ERR(lgdev->private))
-		return PTR_ERR(lgdev->private);
-
-	/* We bind a single DMA buffer at key LGUEST_CONSOLE_DMA_KEY.
-	 * "cons_input" is that statically-initialized global DMA buffer we saw
-	 * above, and we also give the interrupt we want. */
-	err = lguest_bind_dma(LGUEST_CONSOLE_DMA_KEY, &cons_input, 1,
-			      lgdev_irq(lgdev));
-	if (err)
-		printk("lguest console: failed to bind buffer.\n");
-	return err;
-}
-/* Note the use of lgdev_irq() for the interrupt number.  We tell hvc_alloc()
- * to expect input when this interrupt is triggered, and then tell
- * lguest_bind_dma() that is the interrupt to send us when input comes in. */
-
-/*D:360 From now on the console driver follows standard Guest driver form:
- * register_lguest_driver() registers the device type and probe function, and
- * the probe function sets up the device.
- *
- * The standard "struct lguest_driver": */
-static struct lguest_driver lguestcons_drv = {
-	.name = "lguestcons",
-	.owner = THIS_MODULE,
-	.device_type = LGUEST_DEVICE_T_CONSOLE,
-	.probe = lguestcons_probe,
-};
-
-/* The standard init function */
-static int __init hvc_lguest_init(void)
-{
-	return register_lguest_driver(&lguestcons_drv);
-}
-module_init(hvc_lguest_init);
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
new file mode 100644
index 0000000..100e8a2
--- /dev/null
+++ b/drivers/char/virtio_console.c
@@ -0,0 +1,225 @@
+/*D:300
+ * The Guest console driver
+ *
+ * Writing console drivers is one of the few remaining Dark Arts in Linux.
+ * Fortunately for us, the path of virtual consoles has been well-trodden by
+ * the PowerPC folks, who wrote "hvc_console.c" to generically support any
+ * virtual console.  We use that infrastructure which only requires us to write
+ * the basic put_chars and get_chars functions and call the right register
+ * functions.
+ :*/
+
+/*M:002 The console can be flooded: while the Guest is processing input the
+ * Host can send more.  Buffering in the Host could alleviate this, but it is a
+ * difficult problem in general. :*/
+/* Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/virtio.h>
+#include <linux/virtio_console.h>
+#include "hvc_console.h"
+
+/*D:340 These represent our input and output console queues, and the virtio
+ * operations for them. */
+static struct virtqueue *in_vq, *out_vq;
+static struct virtio_device *vdev;
+
+/* This is our input buffer, and how much data is left in it. */
+static unsigned int in_len;
+static char *in, *inbuf;
+
+/* The operations for our console. */
+static struct hv_ops virtio_cons;
+
+/*D:310 The put_chars() callback is pretty straightforward.
+ *
+ * We turn the characters into a scatter-gather list, add it to the output
+ * queue and then kick the Host.  Then we sit here waiting for it to finish:
+ * inefficient in theory, but in practice implementations will do it
+ * immediately (lguest's Launcher does). */
+static int put_chars(u32 vtermno, const char *buf, int count)
+{
+	struct scatterlist sg[1];
+	unsigned int len;
+
+	/* This is a convenient routine to initialize a single-elem sg list */
+	sg_init_one(sg, buf, count);
+
+	/* add_buf wants a token to identify this buffer: we hand it any
+	 * non-NULL pointer, since there's only ever one buffer. */
+	if (out_vq->vq_ops->add_buf(out_vq, sg, 1, 0, (void *)1) == 0) {
+		/* Tell Host to go! */
+		out_vq->vq_ops->kick(out_vq);
+		/* Chill out until it's done with the buffer. */
+		while (!out_vq->vq_ops->get_buf(out_vq, &len))
+			cpu_relax();
+	}
+
+	/* We're expected to return the amount of data we wrote: all of it. */
+	return count;
+}
+
+/* Create a scatter-gather list representing our input buffer and put it in the
+ * queue. */
+static void add_inbuf(void)
+{
+	struct scatterlist sg[1];
+	sg_init_one(sg, inbuf, PAGE_SIZE);
+
+	/* We should always be able to add one buffer to an empty queue. */
+	if (in_vq->vq_ops->add_buf(in_vq, sg, 0, 1, inbuf) != 0)
+		BUG();
+	in_vq->vq_ops->kick(in_vq);
+}
+
+/*D:350 get_chars() is the callback from the hvc_console infrastructure when
+ * an interrupt is received.
+ *
+ * Most of the code deals with the fact that the hvc_console() infrastructure
+ * only asks us for 16 bytes at a time.  We keep in_offset and in_used fields
+ * for partially-filled buffers. */
+static int get_chars(u32 vtermno, char *buf, int count)
+{
+	/* If we don't have an input queue yet, we can't get input. */
+	BUG_ON(!in_vq);
+
+	/* No buffer?  Try to get one. */
+	if (!in_len) {
+		in = in_vq->vq_ops->get_buf(in_vq, &in_len);
+		if (!in)
+			return 0;
+	}
+
+	/* You want more than we have to give?  Well, try wanting less! */
+	if (in_len < count)
+		count = in_len;
+
+	/* Copy across to their buffer and increment offset. */
+	memcpy(buf, in, count);
+	in += count;
+	in_len -= count;
+
+	/* Finished?  Re-register buffer so Host will use it again. */
+	if (in_len == 0)
+		add_inbuf();
+
+	return count;
+}
+/*:*/
+
+/*D:320 Console drivers are initialized very early so boot messages can go out,
+ * so we do things slightly differently from the generic virtio initialization
+ * of the net and block drivers.
+ *
+ * At this stage, the console is output-only.  It's too early to set up a
+ * virtqueue, so we let the drivers do some boutique early-output thing. */
+int __init virtio_cons_early_init(int (*put_chars)(u32, const char *, int))
+{
+	virtio_cons.put_chars = put_chars;
+	return hvc_instantiate(0, 0, &virtio_cons);
+}
+
+/*D:370 Once we're further in boot, we get probed like any other virtio device.
+ * At this stage we set up the output virtqueue.
+ *
+ * To set up and manage our virtual console, we call hvc_alloc().  Since we
+ * never remove the console device we never need this pointer again.
+ *
+ * Finally we put our input buffer in the input queue, ready to receive. */
+static int virtcons_probe(struct virtio_device *dev)
+{
+	int err;
+	struct hvc_struct *hvc;
+
+	vdev = dev;
+
+	/* This is the scratch page we use to receive console input */
+	inbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!inbuf) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	/* Find the input queue. */
+	/* FIXME: This is why we want to wean off hvc: we do nothing
+	 * when input comes in. */
+	in_vq = vdev->config->find_vq(vdev, NULL);
+	if (IS_ERR(in_vq)) {
+		err = PTR_ERR(in_vq);
+		goto free;
+	}
+
+	out_vq = vdev->config->find_vq(vdev, NULL);
+	if (IS_ERR(out_vq)) {
+		err = PTR_ERR(out_vq);
+		goto free_in_vq;
+	}
+
+	/* Start using the new console output. */
+	virtio_cons.get_chars = get_chars;
+	virtio_cons.put_chars = put_chars;
+
+	/* The first argument of hvc_alloc() is the virtual console number, so
+	 * we use zero.  The second argument is the interrupt number; we
+	 * currently leave this as zero: it would be better not to use the
+	 * hvc mechanism and fix this (FIXME!).
+	 *
+	 * The third argument is a "struct hv_ops" containing the put_chars()
+	 * and get_chars() pointers.  The final argument is the output buffer
+	 * size: we can do any size, so we put PAGE_SIZE here. */
+	hvc = hvc_alloc(0, 0, &virtio_cons, PAGE_SIZE);
+	if (IS_ERR(hvc)) {
+		err = PTR_ERR(hvc);
+		goto free_out_vq;
+	}
+
+	/* Register the input buffer the first time. */
+	add_inbuf();
+	return 0;
+
+free_out_vq:
+	vdev->config->del_vq(out_vq);
+free_in_vq:
+	vdev->config->del_vq(in_vq);
+free:
+	kfree(inbuf);
+fail:
+	return err;
+}
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_CONSOLE, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static struct virtio_driver virtio_console = {
+	.driver.name =	KBUILD_MODNAME,
+	.driver.owner =	THIS_MODULE,
+	.id_table =	id_table,
+	.probe =	virtcons_probe,
+};
+
+static int __init init(void)
+{
+	return register_virtio_driver(&virtio_console);
+}
+module_init(init);
+
+MODULE_DEVICE_TABLE(virtio, id_table);
+MODULE_DESCRIPTION("Virtio console driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/kvm/Kconfig b/drivers/kvm/Kconfig
index 8749fa4..6569206 100644
--- a/drivers/kvm/Kconfig
+++ b/drivers/kvm/Kconfig
@@ -47,4 +47,8 @@ config KVM_AMD
 	  Provides support for KVM on AMD processors equipped with the AMD-V
 	  (SVM) extensions.
 
+# OK, it's a little counter-intuitive to do this, but it puts it neatly under
+# the virtualization menu.
+source drivers/lguest/Kconfig
+
 endif # VIRTUALIZATION
diff --git a/drivers/lguest/Kconfig b/drivers/lguest/Kconfig
index 41e2250..7eb9ecf 100644
--- a/drivers/lguest/Kconfig
+++ b/drivers/lguest/Kconfig
@@ -1,7 +1,6 @@
 config LGUEST
 	tristate "Linux hypervisor example code"
-	depends on X86 && PARAVIRT && EXPERIMENTAL && !X86_PAE && FUTEX
-	select LGUEST_GUEST
+	depends on X86_32 && EXPERIMENTAL && !X86_PAE && FUTEX && !(X86_VISWS || X86_VOYAGER)
 	select HVC_DRIVER
 	---help---
 	  This is a very simple module which allows you to run
@@ -18,13 +17,3 @@ config LGUEST_GUEST
 	  The guest needs code built-in, even if the host has lguest
 	  support as a module.  The drivers are tiny, so we build them
 	  in too.
-
-config LGUEST_NET
-	tristate
-	default y
-	depends on LGUEST_GUEST && NET
-
-config LGUEST_BLOCK
-	tristate
-	default y
-	depends on LGUEST_GUEST && BLOCK
diff --git a/drivers/lguest/Makefile b/drivers/lguest/Makefile
index e504747..5e8272d 100644
--- a/drivers/lguest/Makefile
+++ b/drivers/lguest/Makefile
@@ -1,10 +1,12 @@
-# Guest requires the paravirt_ops replacement and the bus driver.
-obj-$(CONFIG_LGUEST_GUEST) += lguest.o lguest_asm.o lguest_bus.o
+# Guest requires the device configuration and probing code.
+obj-$(CONFIG_LGUEST_GUEST) += lguest_device.o
 
 # Host requires the other files, which can be a module.
 obj-$(CONFIG_LGUEST)	+= lg.o
-lg-y := core.o hypercalls.o page_tables.o interrupts_and_traps.o \
-	segments.o io.o lguest_user.o switcher.o
+lg-y = core.o hypercalls.o page_tables.o interrupts_and_traps.o \
+	segments.o lguest_user.o
+
+lg-$(CONFIG_X86_32) += x86/switcher_32.o x86/core.o
 
 Preparation Preparation!: PREFIX=P
 Guest: PREFIX=G
diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
index a0788c1..35d19ae 100644
--- a/drivers/lguest/core.c
+++ b/drivers/lguest/core.c
@@ -11,58 +11,20 @@
 #include <linux/vmalloc.h>
 #include <linux/cpu.h>
 #include <linux/freezer.h>
+#include <linux/highmem.h>
 #include <asm/paravirt.h>
-#include <asm/desc.h>
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>
 #include <asm/poll.h>
-#include <asm/highmem.h>
 #include <asm/asm-offsets.h>
-#include <asm/i387.h>
 #include "lg.h"
 
-/* Found in switcher.S */
-extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];
-extern unsigned long default_idt_entries[];
-
-/* Every guest maps the core switcher code. */
-#define SHARED_SWITCHER_PAGES \
-	DIV_ROUND_UP(end_switcher_text - start_switcher_text, PAGE_SIZE)
-/* Pages for switcher itself, then two pages per cpu */
-#define TOTAL_SWITCHER_PAGES (SHARED_SWITCHER_PAGES + 2 * NR_CPUS)
-
-/* We map at -4M for ease of mapping into the guest (one PTE page). */
-#define SWITCHER_ADDR 0xFFC00000
 
 static struct vm_struct *switcher_vma;
 static struct page **switcher_page;
 
-static int cpu_had_pge;
-static struct {
-	unsigned long offset;
-	unsigned short segment;
-} lguest_entry;
-
 /* This One Big lock protects all inter-guest data structures. */
 DEFINE_MUTEX(lguest_lock);
-static DEFINE_PER_CPU(struct lguest *, last_guest);
-
-/* FIXME: Make dynamic. */
-#define MAX_LGUEST_GUESTS 16
-struct lguest lguests[MAX_LGUEST_GUESTS];
-
-/* Offset from where switcher.S was compiled to where we've copied it */
-static unsigned long switcher_offset(void)
-{
-	return SWITCHER_ADDR - (unsigned long)start_switcher_text;
-}
-
-/* This cpu's struct lguest_pages. */
-static struct lguest_pages *lguest_pages(unsigned int cpu)
-{
-	return &(((struct lguest_pages *)
-		  (SWITCHER_ADDR + SHARED_SWITCHER_PAGES*PAGE_SIZE))[cpu]);
-}
 
 /*H:010 We need to set up the Switcher at a high virtual address.  Remember the
  * Switcher is a few hundred bytes of assembler code which actually changes the
@@ -73,9 +35,7 @@ static struct lguest_pages *lguest_pages(unsigned int cpu)
  * Host since it will be running as the switchover occurs.
  *
  * Trying to map memory at a particular address is an unusual thing to do, so
- * it's not a simple one-liner.  We also set up the per-cpu parts of the
- * Switcher here.
- */
+ * it's not a simple one-liner. */
 static __init int map_switcher(void)
 {
 	int i, err;
@@ -132,90 +92,11 @@ static __init int map_switcher(void)
 		goto free_vma;
 	}
 
-	/* Now the switcher is mapped at the right address, we can't fail!
-	 * Copy in the compiled-in Switcher code (from switcher.S). */
+	/* Now the Switcher is mapped at the right address, we can't fail!
+	 * Copy in the compiled-in Switcher code (from <arch>_switcher.S). */
 	memcpy(switcher_vma->addr, start_switcher_text,
 	       end_switcher_text - start_switcher_text);
 
-	/* Most of the switcher.S doesn't care that it's been moved; on Intel,
-	 * jumps are relative, and it doesn't access any references to external
-	 * code or data.
-	 *
-	 * The only exception is the interrupt handlers in switcher.S: their
-	 * addresses are placed in a table (default_idt_entries), so we need to
-	 * update the table with the new addresses.  switcher_offset() is a
-	 * convenience function which returns the distance between the builtin
-	 * switcher code and the high-mapped copy we just made. */
-	for (i = 0; i < IDT_ENTRIES; i++)
-		default_idt_entries[i] += switcher_offset();
-
-	/*
-	 * Set up the Switcher's per-cpu areas.
-	 *
-	 * Each CPU gets two pages of its own within the high-mapped region
-	 * (aka. "struct lguest_pages").  Much of this can be initialized now,
-	 * but some depends on what Guest we are running (which is set up in
-	 * copy_in_guest_info()).
-	 */
-	for_each_possible_cpu(i) {
-		/* lguest_pages() returns this CPU's two pages. */
-		struct lguest_pages *pages = lguest_pages(i);
-		/* This is a convenience pointer to make the code fit one
-		 * statement to a line. */
-		struct lguest_ro_state *state = &pages->state;
-
-		/* The Global Descriptor Table: the Host has a different one
-		 * for each CPU.  We keep a descriptor for the GDT which says
-		 * where it is and how big it is (the size is actually the last
-		 * byte, not the size, hence the "-1"). */
-		state->host_gdt_desc.size = GDT_SIZE-1;
-		state->host_gdt_desc.address = (long)get_cpu_gdt_table(i);
-
-		/* All CPUs on the Host use the same Interrupt Descriptor
-		 * Table, so we just use store_idt(), which gets this CPU's IDT
-		 * descriptor. */
-		store_idt(&state->host_idt_desc);
-
-		/* The descriptors for the Guest's GDT and IDT can be filled
-		 * out now, too.  We copy the GDT & IDT into ->guest_gdt and
-		 * ->guest_idt before actually running the Guest. */
-		state->guest_idt_desc.size = sizeof(state->guest_idt)-1;
-		state->guest_idt_desc.address = (long)&state->guest_idt;
-		state->guest_gdt_desc.size = sizeof(state->guest_gdt)-1;
-		state->guest_gdt_desc.address = (long)&state->guest_gdt;
-
-		/* We know where we want the stack to be when the Guest enters
-		 * the switcher: in pages->regs.  The stack grows upwards, so
-		 * we start it at the end of that structure. */
-		state->guest_tss.esp0 = (long)(&pages->regs + 1);
-		/* And this is the GDT entry to use for the stack: we keep a
-		 * couple of special LGUEST entries. */
-		state->guest_tss.ss0 = LGUEST_DS;
-
-		/* x86 can have a finegrained bitmap which indicates what I/O
-		 * ports the process can use.  We set it to the end of our
-		 * structure, meaning "none". */
-		state->guest_tss.io_bitmap_base = sizeof(state->guest_tss);
-
-		/* Some GDT entries are the same across all Guests, so we can
-		 * set them up now. */
-		setup_default_gdt_entries(state);
-		/* Most IDT entries are the same for all Guests, too.*/
-		setup_default_idt_entries(state, default_idt_entries);
-
-		/* The Host needs to be able to use the LGUEST segments on this
-		 * CPU, too, so put them in the Host GDT. */
-		get_cpu_gdt_table(i)[GDT_ENTRY_LGUEST_CS] = FULL_EXEC_SEGMENT;
-		get_cpu_gdt_table(i)[GDT_ENTRY_LGUEST_DS] = FULL_SEGMENT;
-	}
-
-	/* In the Switcher, we want the %cs segment register to use the
-	 * LGUEST_CS GDT entry: we've put that in the Host and Guest GDTs, so
-	 * it will be undisturbed when we switch.  To change %cs and jump we
-	 * need this structure to feed to Intel's "lcall" instruction. */
-	lguest_entry.offset = (long)switch_to_guest + switcher_offset();
-	lguest_entry.segment = LGUEST_CS;
-
 	printk(KERN_INFO "lguest: mapped switcher at %p\n",
 	       switcher_vma->addr);
 	/* And we succeeded... */
@@ -247,86 +128,12 @@ static void unmap_switcher(void)
 		__free_pages(switcher_page[i], 0);
 }
 
-/*H:130 Our Guest is usually so well behaved; it never tries to do things it
- * isn't allowed to.  Unfortunately, Linux's paravirtual infrastructure isn't
- * quite complete, because it doesn't contain replacements for the Intel I/O
- * instructions.  As a result, the Guest sometimes fumbles across one during
- * the boot process as it probes for various things which are usually attached
- * to a PC.
- *
- * When the Guest uses one of these instructions, we get trap #13 (General
- * Protection Fault) and come here.  We see if it's one of those troublesome
- * instructions and skip over it.  We return true if we did. */
-static int emulate_insn(struct lguest *lg)
-{
-	u8 insn;
-	unsigned int insnlen = 0, in = 0, shift = 0;
-	/* The eip contains the *virtual* address of the Guest's instruction:
-	 * guest_pa just subtracts the Guest's page_offset. */
-	unsigned long physaddr = guest_pa(lg, lg->regs->eip);
-
-	/* The guest_pa() function only works for Guest kernel addresses, but
-	 * that's all we're trying to do anyway. */
-	if (lg->regs->eip < lg->page_offset)
-		return 0;
-
-	/* Decoding x86 instructions is icky. */
-	lgread(lg, &insn, physaddr, 1);
-
-	/* 0x66 is an "operand prefix".  It means it's using the upper 16 bits
-	   of the eax register. */
-	if (insn == 0x66) {
-		shift = 16;
-		/* The instruction is 1 byte so far, read the next byte. */
-		insnlen = 1;
-		lgread(lg, &insn, physaddr + insnlen, 1);
-	}
-
-	/* We can ignore the lower bit for the moment and decode the 4 opcodes
-	 * we need to emulate. */
-	switch (insn & 0xFE) {
-	case 0xE4: /* in     <next byte>,%al */
-		insnlen += 2;
-		in = 1;
-		break;
-	case 0xEC: /* in     (%dx),%al */
-		insnlen += 1;
-		in = 1;
-		break;
-	case 0xE6: /* out    %al,<next byte> */
-		insnlen += 2;
-		break;
-	case 0xEE: /* out    %al,(%dx) */
-		insnlen += 1;
-		break;
-	default:
-		/* OK, we don't know what this is, can't emulate. */
-		return 0;
-	}
-
-	/* If it was an "IN" instruction, they expect the result to be read
-	 * into %eax, so we change %eax.  We always return all-ones, which
-	 * traditionally means "there's nothing there". */
-	if (in) {
-		/* Lower bit tells is whether it's a 16 or 32 bit access */
-		if (insn & 0x1)
-			lg->regs->eax = 0xFFFFFFFF;
-		else
-			lg->regs->eax |= (0xFFFF << shift);
-	}
-	/* Finally, we've "done" the instruction, so move past it. */
-	lg->regs->eip += insnlen;
-	/* Success! */
-	return 1;
-}
-/*:*/
-
 /*L:305
  * Dealing With Guest Memory.
  *
  * When the Guest gives us (what it thinks is) a physical address, we can use
- * the normal copy_from_user() & copy_to_user() on that address: remember,
- * Guest physical == Launcher virtual.
+ * the normal copy_from_user() & copy_to_user() on the corresponding place in
+ * the memory region allocated by the Launcher.
  *
  * But we can't trust the Guest: it might be trying to access the Launcher
  * code.  We have to check that the range is below the pfn_limit the Launcher
@@ -338,148 +145,27 @@ int lguest_address_ok(const struct lguest *lg,
 	return (addr+len) / PAGE_SIZE < lg->pfn_limit && (addr+len >= addr);
 }
 
-/* This is a convenient routine to get a 32-bit value from the Guest (a very
- * common operation).  Here we can see how useful the kill_lguest() routine we
- * met in the Launcher can be: we return a random value (0) instead of needing
- * to return an error. */
-u32 lgread_u32(struct lguest *lg, unsigned long addr)
-{
-	u32 val = 0;
-
-	/* Don't let them access lguest binary. */
-	if (!lguest_address_ok(lg, addr, sizeof(val))
-	    || get_user(val, (u32 __user *)addr) != 0)
-		kill_guest(lg, "bad read address %#lx", addr);
-	return val;
-}
-
-/* Same thing for writing a value. */
-void lgwrite_u32(struct lguest *lg, unsigned long addr, u32 val)
-{
-	if (!lguest_address_ok(lg, addr, sizeof(val))
-	    || put_user(val, (u32 __user *)addr) != 0)
-		kill_guest(lg, "bad write address %#lx", addr);
-}
-
-/* This routine is more generic, and copies a range of Guest bytes into a
- * buffer.  If the copy_from_user() fails, we fill the buffer with zeroes, so
- * the caller doesn't end up using uninitialized kernel memory. */
-void lgread(struct lguest *lg, void *b, unsigned long addr, unsigned bytes)
+/* This routine copies memory from the Guest.  Here we can see how useful the
+ * kill_lguest() routine we met in the Launcher can be: we return a random
+ * value (all zeroes) instead of needing to return an error. */
+void __lgread(struct lguest *lg, void *b, unsigned long addr, unsigned bytes)
 {
 	if (!lguest_address_ok(lg, addr, bytes)
-	    || copy_from_user(b, (void __user *)addr, bytes) != 0) {
+	    || copy_from_user(b, lg->mem_base + addr, bytes) != 0) {
 		/* copy_from_user should do this, but as we rely on it... */
 		memset(b, 0, bytes);
 		kill_guest(lg, "bad read address %#lx len %u", addr, bytes);
 	}
 }
 
-/* Similarly, our generic routine to copy into a range of Guest bytes. */
-void lgwrite(struct lguest *lg, unsigned long addr, const void *b,
-	     unsigned bytes)
+/* This is the write (copy into guest) version. */
+void __lgwrite(struct lguest *lg, unsigned long addr, const void *b,
+	       unsigned bytes)
 {
 	if (!lguest_address_ok(lg, addr, bytes)
-	    || copy_to_user((void __user *)addr, b, bytes) != 0)
+	    || copy_to_user(lg->mem_base + addr, b, bytes) != 0)
 		kill_guest(lg, "bad write address %#lx len %u", addr, bytes);
 }
-/* (end of memory access helper routines) :*/
-
-static void set_ts(void)
-{
-	u32 cr0;
-
-	cr0 = read_cr0();
-	if (!(cr0 & 8))
-		write_cr0(cr0|8);
-}
-
-/*S:010
- * We are getting close to the Switcher.
- *
- * Remember that each CPU has two pages which are visible to the Guest when it
- * runs on that CPU.  This has to contain the state for that Guest: we copy the
- * state in just before we run the Guest.
- *
- * Each Guest has "changed" flags which indicate what has changed in the Guest
- * since it last ran.  We saw this set in interrupts_and_traps.c and
- * segments.c.
- */
-static void copy_in_guest_info(struct lguest *lg, struct lguest_pages *pages)
-{
-	/* Copying all this data can be quite expensive.  We usually run the
-	 * same Guest we ran last time (and that Guest hasn't run anywhere else
-	 * meanwhile).  If that's not the case, we pretend everything in the
-	 * Guest has changed. */
-	if (__get_cpu_var(last_guest) != lg || lg->last_pages != pages) {
-		__get_cpu_var(last_guest) = lg;
-		lg->last_pages = pages;
-		lg->changed = CHANGED_ALL;
-	}
-
-	/* These copies are pretty cheap, so we do them unconditionally: */
-	/* Save the current Host top-level page directory. */
-	pages->state.host_cr3 = __pa(current->mm->pgd);
-	/* Set up the Guest's page tables to see this CPU's pages (and no
-	 * other CPU's pages). */
-	map_switcher_in_guest(lg, pages);
-	/* Set up the two "TSS" members which tell the CPU what stack to use
-	 * for traps which do directly into the Guest (ie. traps at privilege
-	 * level 1). */
-	pages->state.guest_tss.esp1 = lg->esp1;
-	pages->state.guest_tss.ss1 = lg->ss1;
-
-	/* Copy direct-to-Guest trap entries. */
-	if (lg->changed & CHANGED_IDT)
-		copy_traps(lg, pages->state.guest_idt, default_idt_entries);
-
-	/* Copy all GDT entries which the Guest can change. */
-	if (lg->changed & CHANGED_GDT)
-		copy_gdt(lg, pages->state.guest_gdt);
-	/* If only the TLS entries have changed, copy them. */
-	else if (lg->changed & CHANGED_GDT_TLS)
-		copy_gdt_tls(lg, pages->state.guest_gdt);
-
-	/* Mark the Guest as unchanged for next time. */
-	lg->changed = 0;
-}
-
-/* Finally: the code to actually call into the Switcher to run the Guest. */
-static void run_guest_once(struct lguest *lg, struct lguest_pages *pages)
-{
-	/* This is a dummy value we need for GCC's sake. */
-	unsigned int clobber;
-
-	/* Copy the guest-specific information into this CPU's "struct
-	 * lguest_pages". */
-	copy_in_guest_info(lg, pages);
-
-	/* Set the trap number to 256 (impossible value).  If we fault while
-	 * switching to the Guest (bad segment registers or bug), this will
-	 * cause us to abort the Guest. */
-	lg->regs->trapnum = 256;
-
-	/* Now: we push the "eflags" register on the stack, then do an "lcall".
-	 * This is how we change from using the kernel code segment to using
-	 * the dedicated lguest code segment, as well as jumping into the
-	 * Switcher.
-	 *
-	 * The lcall also pushes the old code segment (KERNEL_CS) onto the
-	 * stack, then the address of this call.  This stack layout happens to
-	 * exactly match the stack of an interrupt... */
-	asm volatile("pushf; lcall *lguest_entry"
-		     /* This is how we tell GCC that %eax ("a") and %ebx ("b")
-		      * are changed by this routine.  The "=" means output. */
-		     : "=a"(clobber), "=b"(clobber)
-		     /* %eax contains the pages pointer.  ("0" refers to the
-		      * 0-th argument above, ie "a").  %ebx contains the
-		      * physical address of the Guest's top-level page
-		      * directory. */
-		     : "0"(pages), "1"(__pa(lg->pgdirs[lg->pgdidx].pgdir))
-		     /* We tell gcc that all these registers could change,
-		      * which means we don't have to save and restore them in
-		      * the Switcher. */
-		     : "memory", "%edx", "%ecx", "%edi", "%esi");
-}
 /*:*/
 
 /*H:030 Let's jump straight to the the main loop which runs the Guest.
@@ -489,22 +175,16 @@ int run_guest(struct lguest *lg, unsigned long __user *user)
 {
 	/* We stop running once the Guest is dead. */
 	while (!lg->dead) {
-		/* We need to initialize this, otherwise gcc complains.  It's
-		 * not (yet) clever enough to see that it's initialized when we
-		 * need it. */
-		unsigned int cr2 = 0; /* Damn gcc */
-
-		/* First we run any hypercalls the Guest wants done: either in
-		 * the hypercall ring in "struct lguest_data", or directly by
-		 * using int 31 (LGUEST_TRAP_ENTRY). */
-		do_hypercalls(lg);
-		/* It's possible the Guest did a SEND_DMA hypercall to the
+		/* First we run any hypercalls the Guest wants done. */
+		if (lg->hcall)
+			do_hypercalls(lg);
+
+		/* It's possible the Guest did a NOTIFY hypercall to the
 		 * Launcher, in which case we return from the read() now. */
-		if (lg->dma_is_pending) {
-			if (put_user(lg->pending_dma, user) ||
-			    put_user(lg->pending_key, user+1))
+		if (lg->pending_notify) {
+			if (put_user(lg->pending_notify, user))
 				return -EFAULT;
-			return sizeof(unsigned long)*2;
+			return sizeof(lg->pending_notify);
 		}
 
 		/* Check for signals */
@@ -542,144 +222,20 @@ int run_guest(struct lguest *lg, unsigned long __user *user)
 		 * the "Do Not Disturb" sign: */
 		local_irq_disable();
 
-		/* Remember the awfully-named TS bit?  If the Guest has asked
-		 * to set it we set it now, so we can trap and pass that trap
-		 * to the Guest if it uses the FPU. */
-		if (lg->ts)
-			set_ts();
-
-		/* SYSENTER is an optimized way of doing system calls.  We
-		 * can't allow it because it always jumps to privilege level 0.
-		 * A normal Guest won't try it because we don't advertise it in
-		 * CPUID, but a malicious Guest (or malicious Guest userspace
-		 * program) could, so we tell the CPU to disable it before
-		 * running the Guest. */
-		if (boot_cpu_has(X86_FEATURE_SEP))
-			wrmsr(MSR_IA32_SYSENTER_CS, 0, 0);
-
-		/* Now we actually run the Guest.  It will pop back out when
-		 * something interesting happens, and we can examine its
-		 * registers to see what it was doing. */
-		run_guest_once(lg, lguest_pages(raw_smp_processor_id()));
-
-		/* The "regs" pointer contains two extra entries which are not
-		 * really registers: a trap number which says what interrupt or
-		 * trap made the switcher code come back, and an error code
-		 * which some traps set.  */
-
-		/* If the Guest page faulted, then the cr2 register will tell
-		 * us the bad virtual address.  We have to grab this now,
-		 * because once we re-enable interrupts an interrupt could
-		 * fault and thus overwrite cr2, or we could even move off to a
-		 * different CPU. */
-		if (lg->regs->trapnum == 14)
-			cr2 = read_cr2();
-		/* Similarly, if we took a trap because the Guest used the FPU,
-		 * we have to restore the FPU it expects to see. */
-		else if (lg->regs->trapnum == 7)
-			math_state_restore();
-
-		/* Restore SYSENTER if it's supposed to be on. */
-		if (boot_cpu_has(X86_FEATURE_SEP))
-			wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
+		/* Actually run the Guest until something happens. */
+		lguest_arch_run_guest(lg);
 
 		/* Now we're ready to be interrupted or moved to other CPUs */
 		local_irq_enable();
 
-		/* OK, so what happened? */
-		switch (lg->regs->trapnum) {
-		case 13: /* We've intercepted a GPF. */
-			/* Check if this was one of those annoying IN or OUT
-			 * instructions which we need to emulate.  If so, we
-			 * just go back into the Guest after we've done it. */
-			if (lg->regs->errcode == 0) {
-				if (emulate_insn(lg))
-					continue;
-			}
-			break;
-		case 14: /* We've intercepted a page fault. */
-			/* The Guest accessed a virtual address that wasn't
-			 * mapped.  This happens a lot: we don't actually set
-			 * up most of the page tables for the Guest at all when
-			 * we start: as it runs it asks for more and more, and
-			 * we set them up as required. In this case, we don't
-			 * even tell the Guest that the fault happened.
-			 *
-			 * The errcode tells whether this was a read or a
-			 * write, and whether kernel or userspace code. */
-			if (demand_page(lg, cr2, lg->regs->errcode))
-				continue;
-
-			/* OK, it's really not there (or not OK): the Guest
-			 * needs to know.  We write out the cr2 value so it
-			 * knows where the fault occurred.
-			 *
-			 * Note that if the Guest were really messed up, this
-			 * could happen before it's done the INITIALIZE
-			 * hypercall, so lg->lguest_data will be NULL, so
-			 * &lg->lguest_data->cr2 will be address 8.  Writing
-			 * into that address won't hurt the Host at all,
-			 * though. */
-			if (put_user(cr2, &lg->lguest_data->cr2))
-				kill_guest(lg, "Writing cr2");
-			break;
-		case 7: /* We've intercepted a Device Not Available fault. */
-			/* If the Guest doesn't want to know, we already
-			 * restored the Floating Point Unit, so we just
-			 * continue without telling it. */
-			if (!lg->ts)
-				continue;
-			break;
-		case 32 ... 255:
-			/* These values mean a real interrupt occurred, in
-			 * which case the Host handler has already been run.
-			 * We just do a friendly check if another process
-			 * should now be run, then fall through to loop
-			 * around: */
-			cond_resched();
-		case LGUEST_TRAP_ENTRY: /* Handled at top of loop */
-			continue;
-		}
-
-		/* If we get here, it's a trap the Guest wants to know
-		 * about. */
-		if (deliver_trap(lg, lg->regs->trapnum))
-			continue;
-
-		/* If the Guest doesn't have a handler (either it hasn't
-		 * registered any yet, or it's one of the faults we don't let
-		 * it handle), it dies with a cryptic error message. */
-		kill_guest(lg, "unhandled trap %li at %#lx (%#lx)",
-			   lg->regs->trapnum, lg->regs->eip,
-			   lg->regs->trapnum == 14 ? cr2 : lg->regs->errcode);
+		/* Now we deal with whatever happened to the Guest. */
+		lguest_arch_handle_trap(lg);
 	}
+
 	/* The Guest is dead => "No such file or directory" */
 	return -ENOENT;
 }
 
-/* Now we can look at each of the routines this calls, in increasing order of
- * complexity: do_hypercalls(), emulate_insn(), maybe_do_interrupt(),
- * deliver_trap() and demand_page().  After all those, we'll be ready to
- * examine the Switcher, and our philosophical understanding of the Host/Guest
- * duality will be complete. :*/
-
-int find_free_guest(void)
-{
-	unsigned int i;
-	for (i = 0; i < MAX_LGUEST_GUESTS; i++)
-		if (!lguests[i].tsk)
-			return i;
-	return -1;
-}
-
-static void adjust_pge(void *on)
-{
-	if (on)
-		write_cr4(read_cr4() | X86_CR4_PGE);
-	else
-		write_cr4(read_cr4() & ~X86_CR4_PGE);
-}
-
 /*H:000
  * Welcome to the Host!
  *
@@ -701,72 +257,50 @@ static int __init init(void)
 	/* First we put the Switcher up in very high virtual memory. */
 	err = map_switcher();
 	if (err)
-		return err;
+		goto out;
 
 	/* Now we set up the pagetable implementation for the Guests. */
 	err = init_pagetables(switcher_page, SHARED_SWITCHER_PAGES);
-	if (err) {
-		unmap_switcher();
-		return err;
-	}
+	if (err)
+		goto unmap;
 
-	/* The I/O subsystem needs some things initialized. */
-	lguest_io_init();
+	/* We might need to reserve an interrupt vector. */
+	err = init_interrupts();
+	if (err)
+		goto free_pgtables;
 
 	/* /dev/lguest needs to be registered. */
 	err = lguest_device_init();
-	if (err) {
-		free_pagetables();
-		unmap_switcher();
-		return err;
-	}
+	if (err)
+		goto free_interrupts;
 
-	/* Finally, we need to turn off "Page Global Enable".  PGE is an
-	 * optimization where page table entries are specially marked to show
-	 * they never change.  The Host kernel marks all the kernel pages this
-	 * way because it's always present, even when userspace is running.
-	 *
-	 * Lguest breaks this: unbeknownst to the rest of the Host kernel, we
-	 * switch to the Guest kernel.  If you don't disable this on all CPUs,
-	 * you'll get really weird bugs that you'll chase for two days.
-	 *
-	 * I used to turn PGE off every time we switched to the Guest and back
-	 * on when we return, but that slowed the Switcher down noticibly. */
-
-	/* We don't need the complexity of CPUs coming and going while we're
-	 * doing this. */
-	lock_cpu_hotplug();
-	if (cpu_has_pge) { /* We have a broader idea of "global". */
-		/* Remember that this was originally set (for cleanup). */
-		cpu_had_pge = 1;
-		/* adjust_pge is a helper function which sets or unsets the PGE
-		 * bit on its CPU, depending on the argument (0 == unset). */
-		on_each_cpu(adjust_pge, (void *)0, 0, 1);
-		/* Turn off the feature in the global feature set. */
-		clear_bit(X86_FEATURE_PGE, boot_cpu_data.x86_capability);
-	}
-	unlock_cpu_hotplug();
+	/* Finally we do some architecture-specific setup. */
+	lguest_arch_host_init();
 
 	/* All good! */
 	return 0;
+
+free_interrupts:
+	free_interrupts();
+free_pgtables:
+	free_pagetables();
+unmap:
+	unmap_switcher();
+out:
+	return err;
 }
 
 /* Cleaning up is just the same code, backwards.  With a little French. */
 static void __exit fini(void)
 {
 	lguest_device_remove();
+	free_interrupts();
 	free_pagetables();
 	unmap_switcher();
 
-	/* If we had PGE before we started, turn it back on now. */
-	lock_cpu_hotplug();
-	if (cpu_had_pge) {
-		set_bit(X86_FEATURE_PGE, boot_cpu_data.x86_capability);
-		/* adjust_pge's argument "1" means set PGE. */
-		on_each_cpu(adjust_pge, (void *)1, 0, 1);
-	}
-	unlock_cpu_hotplug();
+	lguest_arch_host_fini();
 }
+/*:*/
 
 /* The Host side of lguest can be a module.  This is a nice way for people to
  * play with it.  */
diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c
index db6caac..9d5184c 100644
--- a/drivers/lguest/hypercalls.c
+++ b/drivers/lguest/hypercalls.c
@@ -25,17 +25,13 @@
 #include <linux/mm.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
-#include <irq_vectors.h>
 #include "lg.h"
 
-/*H:120 This is the core hypercall routine: where the Guest gets what it
- * wants.  Or gets killed.  Or, in the case of LHCALL_CRASH, both.
- *
- * Remember from the Guest: %eax == which call to make, and the arguments are
- * packed into %edx, %ebx and %ecx if needed. */
-static void do_hcall(struct lguest *lg, struct lguest_regs *regs)
+/*H:120 This is the core hypercall routine: where the Guest gets what it wants.
+ * Or gets killed.  Or, in the case of LHCALL_CRASH, both. */
+static void do_hcall(struct lguest *lg, struct hcall_args *args)
 {
-	switch (regs->eax) {
+	switch (args->arg0) {
 	case LHCALL_FLUSH_ASYNC:
 		/* This call does nothing, except by breaking out of the Guest
 		 * it makes us process all the asynchronous hypercalls. */
@@ -51,7 +47,7 @@ static void do_hcall(struct lguest *lg, struct lguest_regs *regs)
 		char msg[128];
 		/* If the lgread fails, it will call kill_guest() itself; the
 		 * kill_guest() with the message will be ignored. */
-		lgread(lg, msg, regs->edx, sizeof(msg));
+		__lgread(lg, msg, args->arg1, sizeof(msg));
 		msg[sizeof(msg)-1] = '\0';
 		kill_guest(lg, "CRASH: %s", msg);
 		break;
@@ -59,67 +55,49 @@ static void do_hcall(struct lguest *lg, struct lguest_regs *regs)
 	case LHCALL_FLUSH_TLB:
 		/* FLUSH_TLB comes in two flavors, depending on the
 		 * argument: */
-		if (regs->edx)
+		if (args->arg1)
 			guest_pagetable_clear_all(lg);
 		else
 			guest_pagetable_flush_user(lg);
 		break;
-	case LHCALL_BIND_DMA:
-		/* BIND_DMA really wants four arguments, but it's the only call
-		 * which does.  So the Guest packs the number of buffers and
-		 * the interrupt number into the final argument, and we decode
-		 * it here.  This can legitimately fail, since we currently
-		 * place a limit on the number of DMA pools a Guest can have.
-		 * So we return true or false from this call. */
-		regs->eax = bind_dma(lg, regs->edx, regs->ebx,
-				     regs->ecx >> 8, regs->ecx & 0xFF);
-		break;
 
 	/* All these calls simply pass the arguments through to the right
 	 * routines. */
-	case LHCALL_SEND_DMA:
-		send_dma(lg, regs->edx, regs->ebx);
-		break;
-	case LHCALL_LOAD_GDT:
-		load_guest_gdt(lg, regs->edx, regs->ebx);
-		break;
-	case LHCALL_LOAD_IDT_ENTRY:
-		load_guest_idt_entry(lg, regs->edx, regs->ebx, regs->ecx);
-		break;
 	case LHCALL_NEW_PGTABLE:
-		guest_new_pagetable(lg, regs->edx);
+		guest_new_pagetable(lg, args->arg1);
 		break;
 	case LHCALL_SET_STACK:
-		guest_set_stack(lg, regs->edx, regs->ebx, regs->ecx);
+		guest_set_stack(lg, args->arg1, args->arg2, args->arg3);
 		break;
 	case LHCALL_SET_PTE:
-		guest_set_pte(lg, regs->edx, regs->ebx, mkgpte(regs->ecx));
+		guest_set_pte(lg, args->arg1, args->arg2, __pte(args->arg3));
 		break;
 	case LHCALL_SET_PMD:
-		guest_set_pmd(lg, regs->edx, regs->ebx);
-		break;
-	case LHCALL_LOAD_TLS:
-		guest_load_tls(lg, regs->edx);
+		guest_set_pmd(lg, args->arg1, args->arg2);
 		break;
 	case LHCALL_SET_CLOCKEVENT:
-		guest_set_clockevent(lg, regs->edx);
+		guest_set_clockevent(lg, args->arg1);
 		break;
-
 	case LHCALL_TS:
 		/* This sets the TS flag, as we saw used in run_guest(). */
-		lg->ts = regs->edx;
+		lg->ts = args->arg1;
 		break;
 	case LHCALL_HALT:
 		/* Similarly, this sets the halted flag for run_guest(). */
 		lg->halted = 1;
 		break;
+	case LHCALL_NOTIFY:
+		lg->pending_notify = args->arg1;
+		break;
 	default:
-		kill_guest(lg, "Bad hypercall %li\n", regs->eax);
+		if (lguest_arch_do_hcall(lg, args))
+			kill_guest(lg, "Bad hypercall %li\n", args->arg0);
 	}
 }
+/*:*/
 
-/* Asynchronous hypercalls are easy: we just look in the array in the Guest's
- * "struct lguest_data" and see if there are any new ones marked "ready".
+/*H:124 Asynchronous hypercalls are easy: we just look in the array in the
+ * Guest's "struct lguest_data" to see if any new ones are marked "ready".
  *
  * We are careful to do these in order: obviously we respect the order the
  * Guest put them in the ring, but we also promise the Guest that they will
@@ -134,10 +112,9 @@ static void do_async_hcalls(struct lguest *lg)
 	if (copy_from_user(&st, &lg->lguest_data->hcall_status, sizeof(st)))
 		return;
 
-
 	/* We process "struct lguest_data"s hcalls[] ring once. */
 	for (i = 0; i < ARRAY_SIZE(st); i++) {
-		struct lguest_regs regs;
+		struct hcall_args args;
 		/* We remember where we were up to from last time.  This makes
 		 * sure that the hypercalls are done in the order the Guest
 		 * places them in the ring. */
@@ -152,18 +129,16 @@ static void do_async_hcalls(struct lguest *lg)
 		if (++lg->next_hcall == LHCALL_RING_SIZE)
 			lg->next_hcall = 0;
 
-		/* We copy the hypercall arguments into a fake register
-		 * structure.  This makes life simple for do_hcall(). */
-		if (get_user(regs.eax, &lg->lguest_data->hcalls[n].eax)
-		    || get_user(regs.edx, &lg->lguest_data->hcalls[n].edx)
-		    || get_user(regs.ecx, &lg->lguest_data->hcalls[n].ecx)
-		    || get_user(regs.ebx, &lg->lguest_data->hcalls[n].ebx)) {
+		/* Copy the hypercall arguments into a local copy of
+		 * the hcall_args struct. */
+		if (copy_from_user(&args, &lg->lguest_data->hcalls[n],
+				   sizeof(struct hcall_args))) {
 			kill_guest(lg, "Fetching async hypercalls");
 			break;
 		}
 
 		/* Do the hypercall, same as a normal one. */
-		do_hcall(lg, &regs);
+		do_hcall(lg, &args);
 
 		/* Mark the hypercall done. */
 		if (put_user(0xFF, &lg->lguest_data->hcall_status[n])) {
@@ -171,9 +146,9 @@ static void do_async_hcalls(struct lguest *lg)
 			break;
 		}
 
- 		/* Stop doing hypercalls if we've just done a DMA to the
-		 * Launcher: it needs to service this first. */
-		if (lg->dma_is_pending)
+		/* Stop doing hypercalls if they want to notify the Launcher:
+		 * it needs to service this first. */
+		if (lg->pending_notify)
 			break;
 	}
 }
@@ -182,76 +157,35 @@ static void do_async_hcalls(struct lguest *lg)
  * Guest makes a hypercall, we end up here to set things up: */
 static void initialize(struct lguest *lg)
 {
-	u32 tsc_speed;
 
 	/* You can't do anything until you're initialized.  The Guest knows the
 	 * rules, so we're unforgiving here. */
-	if (lg->regs->eax != LHCALL_LGUEST_INIT) {
-		kill_guest(lg, "hypercall %li before LGUEST_INIT",
-			   lg->regs->eax);
+	if (lg->hcall->arg0 != LHCALL_LGUEST_INIT) {
+		kill_guest(lg, "hypercall %li before INIT", lg->hcall->arg0);
 		return;
 	}
 
-	/* We insist that the Time Stamp Counter exist and doesn't change with
-	 * cpu frequency.  Some devious chip manufacturers decided that TSC
-	 * changes could be handled in software.  I decided that time going
-	 * backwards might be good for benchmarks, but it's bad for users.
-	 *
-	 * We also insist that the TSC be stable: the kernel detects unreliable
-	 * TSCs for its own purposes, and we use that here. */
-	if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && !check_tsc_unstable())
-		tsc_speed = tsc_khz;
-	else
-		tsc_speed = 0;
-
-	/* The pointer to the Guest's "struct lguest_data" is the only
-	 * argument. */
-	lg->lguest_data = (struct lguest_data __user *)lg->regs->edx;
-	/* If we check the address they gave is OK now, we can simply
-	 * copy_to_user/from_user from now on rather than using lgread/lgwrite.
-	 * I put this in to show that I'm not immune to writing stupid
-	 * optimizations. */
-	if (!lguest_address_ok(lg, lg->regs->edx, sizeof(*lg->lguest_data))) {
+	if (lguest_arch_init_hypercalls(lg))
 		kill_guest(lg, "bad guest page %p", lg->lguest_data);
-		return;
-	}
+
 	/* The Guest tells us where we're not to deliver interrupts by putting
 	 * the range of addresses into "struct lguest_data". */
 	if (get_user(lg->noirq_start, &lg->lguest_data->noirq_start)
-	    || get_user(lg->noirq_end, &lg->lguest_data->noirq_end)
-	    /* We tell the Guest that it can't use the top 4MB of virtual
-	     * addresses used by the Switcher. */
-	    || put_user(4U*1024*1024, &lg->lguest_data->reserve_mem)
-	    || put_user(tsc_speed, &lg->lguest_data->tsc_khz)
-	    /* We also give the Guest a unique id, as used in lguest_net.c. */
-	    || put_user(lg->guestid, &lg->lguest_data->guestid))
+	    || get_user(lg->noirq_end, &lg->lguest_data->noirq_end))
 		kill_guest(lg, "bad guest page %p", lg->lguest_data);
 
 	/* We write the current time into the Guest's data page once now. */
 	write_timestamp(lg);
 
+	/* page_tables.c will also do some setup. */
+	page_table_guest_data_init(lg);
+
 	/* This is the one case where the above accesses might have been the
 	 * first write to a Guest page.  This may have caused a copy-on-write
 	 * fault, but the Guest might be referring to the old (read-only)
 	 * page. */
 	guest_pagetable_clear_all(lg);
 }
-/* Now we've examined the hypercall code; our Guest can make requests.  There
- * is one other way we can do things for the Guest, as we see in
- * emulate_insn(). */
-
-/*H:110 Tricky point: we mark the hypercall as "done" once we've done it.
- * Normally we don't need to do this: the Guest will run again and update the
- * trap number before we come back around the run_guest() loop to
- * do_hypercalls().
- *
- * However, if we are signalled or the Guest sends DMA to the Launcher, that
- * loop will exit without running the Guest.  When it comes back it would try
- * to re-run the hypercall. */
-static void clear_hcall(struct lguest *lg)
-{
-	lg->regs->trapnum = 255;
-}
 
 /*H:100
  * Hypercalls
@@ -261,16 +195,12 @@ static void clear_hcall(struct lguest *lg)
  */
 void do_hypercalls(struct lguest *lg)
 {
-	/* Not initialized yet? */
+	/* Not initialized yet?  This hypercall must do it. */
 	if (unlikely(!lg->lguest_data)) {
-		/* Did the Guest make a hypercall?  We might have come back for
-		 * some other reason (an interrupt, a different trap). */
-		if (lg->regs->trapnum == LGUEST_TRAP_ENTRY) {
-			/* Set up the "struct lguest_data" */
-			initialize(lg);
-			/* The hypercall is done. */
-			clear_hcall(lg);
-		}
+		/* Set up the "struct lguest_data" */
+		initialize(lg);
+		/* Hcall is done. */
+		lg->hcall = NULL;
 		return;
 	}
 
@@ -280,12 +210,21 @@ void do_hypercalls(struct lguest *lg)
 	do_async_hcalls(lg);
 
 	/* If we stopped reading the hypercall ring because the Guest did a
-	 * SEND_DMA to the Launcher, we want to return now.  Otherwise if the
-	 * Guest asked us to do a hypercall, we do it. */
-	if (!lg->dma_is_pending && lg->regs->trapnum == LGUEST_TRAP_ENTRY) {
-		do_hcall(lg, lg->regs);
-		/* The hypercall is done. */
-		clear_hcall(lg);
+	 * NOTIFY to the Launcher, we want to return now.  Otherwise we do
+	 * the hypercall. */
+	if (!lg->pending_notify) {
+		do_hcall(lg, lg->hcall);
+		/* Tricky point: we reset the hcall pointer to mark the
+		 * hypercall as "done".  We use the hcall pointer rather than
+		 * the trap number to indicate a hypercall is pending.
+		 * Normally it doesn't matter: the Guest will run again and
+		 * update the trap number before we come back here.
+		 *
+		 * However, if we are signalled or the Guest sends DMA to the
+		 * Launcher, the run_guest() loop will exit without running the
+		 * Guest.  When it comes back it would try to re-run the
+		 * hypercall. */
+		lg->hcall = NULL;
 	}
 }
 
@@ -295,6 +234,6 @@ void write_timestamp(struct lguest *lg)
 {
 	struct timespec now;
 	ktime_get_real_ts(&now);
-	if (put_user(now, &lg->lguest_data->time))
+	if (copy_to_user(&lg->lguest_data->time, &now, sizeof(struct timespec)))
 		kill_guest(lg, "Writing timestamp");
 }
diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c
index 3973123..8296698 100644
--- a/drivers/lguest/interrupts_and_traps.c
+++ b/drivers/lguest/interrupts_and_traps.c
@@ -12,8 +12,14 @@
  * them first, so we also have a way of "reflecting" them into the Guest as if
  * they had been delivered to it directly. :*/
 #include <linux/uaccess.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
 #include "lg.h"
 
+/* Allow Guests to use a non-128 (ie. non-Linux) syscall trap. */
+static unsigned int syscall_vector = SYSCALL_VECTOR;
+module_param(syscall_vector, uint, 0444);
+
 /* The address of the interrupt handler is split into two bits: */
 static unsigned long idt_address(u32 lo, u32 hi)
 {
@@ -39,7 +45,7 @@ static void push_guest_stack(struct lguest *lg, unsigned long *gstack, u32 val)
 {
 	/* Stack grows upwards: move stack then write value. */
 	*gstack -= 4;
-	lgwrite_u32(lg, *gstack, val);
+	lgwrite(lg, *gstack, u32, val);
 }
 
 /*H:210 The set_guest_interrupt() routine actually delivers the interrupt or
@@ -56,8 +62,9 @@ static void push_guest_stack(struct lguest *lg, unsigned long *gstack, u32 val)
  * it). */
 static void set_guest_interrupt(struct lguest *lg, u32 lo, u32 hi, int has_err)
 {
-	unsigned long gstack;
+	unsigned long gstack, origstack;
 	u32 eflags, ss, irq_enable;
+	unsigned long virtstack;
 
 	/* There are two cases for interrupts: one where the Guest is already
 	 * in the kernel, and a more complex one where the Guest is in
@@ -65,8 +72,10 @@ static void set_guest_interrupt(struct lguest *lg, u32 lo, u32 hi, int has_err)
 	if ((lg->regs->ss&0x3) != GUEST_PL) {
 		/* The Guest told us their kernel stack with the SET_STACK
 		 * hypercall: both the virtual address and the segment */
-		gstack = guest_pa(lg, lg->esp1);
+		virtstack = lg->esp1;
 		ss = lg->ss1;
+
+		origstack = gstack = guest_pa(lg, virtstack);
 		/* We push the old stack segment and pointer onto the new
 		 * stack: when the Guest does an "iret" back from the interrupt
 		 * handler the CPU will notice they're dropping privilege
@@ -75,8 +84,10 @@ static void set_guest_interrupt(struct lguest *lg, u32 lo, u32 hi, int has_err)
 		push_guest_stack(lg, &gstack, lg->regs->esp);
 	} else {
 		/* We're staying on the same Guest (kernel) stack. */
-		gstack = guest_pa(lg, lg->regs->esp);
+		virtstack = lg->regs->esp;
 		ss = lg->regs->ss;
+
+		origstack = gstack = guest_pa(lg, virtstack);
 	}
 
 	/* Remember that we never let the Guest actually disable interrupts, so
@@ -102,7 +113,7 @@ static void set_guest_interrupt(struct lguest *lg, u32 lo, u32 hi, int has_err)
 	/* Now we've pushed all the old state, we change the stack, the code
 	 * segment and the address to execute. */
 	lg->regs->ss = ss;
-	lg->regs->esp = gstack + lg->page_offset;
+	lg->regs->esp = virtstack + (gstack - origstack);
 	lg->regs->cs = (__KERNEL_CS|GUEST_PL);
 	lg->regs->eip = idt_address(lo, hi);
 
@@ -165,7 +176,7 @@ void maybe_do_interrupt(struct lguest *lg)
 	/* Look at the IDT entry the Guest gave us for this interrupt.  The
 	 * first 32 (FIRST_EXTERNAL_VECTOR) entries are for traps, so we skip
 	 * over them. */
-	idt = &lg->idt[FIRST_EXTERNAL_VECTOR+irq];
+	idt = &lg->arch.idt[FIRST_EXTERNAL_VECTOR+irq];
 	/* If they don't have a handler (yet?), we just ignore it */
 	if (idt_present(idt->a, idt->b)) {
 		/* OK, mark it no longer pending and deliver it. */
@@ -183,6 +194,47 @@ void maybe_do_interrupt(struct lguest *lg)
 	 * timer interrupt. */
 	write_timestamp(lg);
 }
+/*:*/
+
+/* Linux uses trap 128 for system calls.  Plan9 uses 64, and Ron Minnich sent
+ * me a patch, so we support that too.  It'd be a big step for lguest if half
+ * the Plan 9 user base were to start using it.
+ *
+ * Actually now I think of it, it's possible that Ron *is* half the Plan 9
+ * userbase.  Oh well. */
+static bool could_be_syscall(unsigned int num)
+{
+	/* Normal Linux SYSCALL_VECTOR or reserved vector? */
+	return num == SYSCALL_VECTOR || num == syscall_vector;
+}
+
+/* The syscall vector it wants must be unused by Host. */
+bool check_syscall_vector(struct lguest *lg)
+{
+	u32 vector;
+
+	if (get_user(vector, &lg->lguest_data->syscall_vec))
+		return false;
+
+	return could_be_syscall(vector);
+}
+
+int init_interrupts(void)
+{
+	/* If they want some strange system call vector, reserve it now */
+	if (syscall_vector != SYSCALL_VECTOR
+	    && test_and_set_bit(syscall_vector, used_vectors)) {
+		printk("lg: couldn't reserve syscall %u\n", syscall_vector);
+		return -EBUSY;
+	}
+	return 0;
+}
+
+void free_interrupts(void)
+{
+	if (syscall_vector != SYSCALL_VECTOR)
+		clear_bit(syscall_vector, used_vectors);
+}
 
 /*H:220 Now we've got the routines to deliver interrupts, delivering traps
  * like page fault is easy.  The only trick is that Intel decided that some
@@ -197,14 +249,14 @@ int deliver_trap(struct lguest *lg, unsigned int num)
 {
 	/* Trap numbers are always 8 bit, but we set an impossible trap number
 	 * for traps inside the Switcher, so check that here. */
-	if (num >= ARRAY_SIZE(lg->idt))
+	if (num >= ARRAY_SIZE(lg->arch.idt))
 		return 0;
 
 	/* Early on the Guest hasn't set the IDT entries (or maybe it put a
 	 * bogus one in): if we fail here, the Guest will be killed. */
-	if (!idt_present(lg->idt[num].a, lg->idt[num].b))
+	if (!idt_present(lg->arch.idt[num].a, lg->arch.idt[num].b))
 		return 0;
-	set_guest_interrupt(lg, lg->idt[num].a, lg->idt[num].b, has_err(num));
+	set_guest_interrupt(lg, lg->arch.idt[num].a, lg->arch.idt[num].b, has_err(num));
 	return 1;
 }
 
@@ -218,28 +270,20 @@ int deliver_trap(struct lguest *lg, unsigned int num)
  * system calls down from 1750ns to 270ns.  Plus, if lguest didn't do it, all
  * the other hypervisors would tease it.
  *
- * This routine determines if a trap can be delivered directly. */
-static int direct_trap(const struct lguest *lg,
-		       const struct desc_struct *trap,
-		       unsigned int num)
+ * This routine indicates if a particular trap number could be delivered
+ * directly. */
+static int direct_trap(unsigned int num)
 {
 	/* Hardware interrupts don't go to the Guest at all (except system
 	 * call). */
-	if (num >= FIRST_EXTERNAL_VECTOR && num != SYSCALL_VECTOR)
+	if (num >= FIRST_EXTERNAL_VECTOR && !could_be_syscall(num))
 		return 0;
 
 	/* The Host needs to see page faults (for shadow paging and to save the
 	 * fault address), general protection faults (in/out emulation) and
 	 * device not available (TS handling), and of course, the hypercall
 	 * trap. */
-	if (num == 14 || num == 13 || num == 7 || num == LGUEST_TRAP_ENTRY)
-		return 0;
-
-	/* Only trap gates (type 15) can go direct to the Guest.  Interrupt
-	 * gates (type 14) disable interrupts as they are entered, which we
-	 * never let the Guest do.  Not present entries (type 0x0) also can't
-	 * go direct, of course 8) */
-	return idt_type(trap->a, trap->b) == 0xF;
+	return num != 14 && num != 13 && num != 7 && num != LGUEST_TRAP_ENTRY;
 }
 /*:*/
 
@@ -348,15 +392,11 @@ void load_guest_idt_entry(struct lguest *lg, unsigned int num, u32 lo, u32 hi)
 	 * to copy this again. */
 	lg->changed |= CHANGED_IDT;
 
-	/* The IDT which we keep in "struct lguest" only contains 32 entries
-	 * for the traps and LGUEST_IRQS (32) entries for interrupts.  We
-	 * ignore attempts to set handlers for higher interrupt numbers, except
-	 * for the system call "interrupt" at 128: we have a special IDT entry
-	 * for that. */
-	if (num < ARRAY_SIZE(lg->idt))
-		set_trap(lg, &lg->idt[num], num, lo, hi);
-	else if (num == SYSCALL_VECTOR)
-		set_trap(lg, &lg->syscall_idt, num, lo, hi);
+	/* Check that the Guest doesn't try to step outside the bounds. */
+	if (num >= ARRAY_SIZE(lg->arch.idt))
+		kill_guest(lg, "Setting idt entry %u", num);
+	else
+		set_trap(lg, &lg->arch.idt[num], num, lo, hi);
 }
 
 /* The default entry for each interrupt points into the Switcher routines which
@@ -399,20 +439,21 @@ void copy_traps(const struct lguest *lg, struct desc_struct *idt,
 
 	/* We can simply copy the direct traps, otherwise we use the default
 	 * ones in the Switcher: they will return to the Host. */
-	for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++) {
-		if (direct_trap(lg, &lg->idt[i], i))
-			idt[i] = lg->idt[i];
+	for (i = 0; i < ARRAY_SIZE(lg->arch.idt); i++) {
+		/* If no Guest can ever override this trap, leave it alone. */
+		if (!direct_trap(i))
+			continue;
+
+		/* Only trap gates (type 15) can go direct to the Guest.
+		 * Interrupt gates (type 14) disable interrupts as they are
+		 * entered, which we never let the Guest do.  Not present
+		 * entries (type 0x0) also can't go direct, of course. */
+		if (idt_type(lg->arch.idt[i].a, lg->arch.idt[i].b) == 0xF)
+			idt[i] = lg->arch.idt[i];
 		else
+			/* Reset it to the default. */
 			default_idt_entry(&idt[i], i, def[i]);
 	}
-
-	/* Don't forget the system call trap!  The IDT entries for other
-	 * interupts never change, so no need to copy them. */
-	i = SYSCALL_VECTOR;
-	if (direct_trap(lg, &lg->syscall_idt, i))
-		idt[i] = lg->syscall_idt;
-	else
-		default_idt_entry(&idt[i], i, def[i]);
 }
 
 void guest_set_clockevent(struct lguest *lg, unsigned long delta)
diff --git a/drivers/lguest/io.c b/drivers/lguest/io.c
deleted file mode 100644
index ea68613..0000000
--- a/drivers/lguest/io.c
+++ /dev/null
@@ -1,626 +0,0 @@
-/*P:300 The I/O mechanism in lguest is simple yet flexible, allowing the Guest
- * to talk to the Launcher or directly to another Guest.  It uses familiar
- * concepts of DMA and interrupts, plus some neat code stolen from
- * futexes... :*/
-
-/* Copyright (C) 2006 Rusty Russell IBM Corporation
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
- */
-#include <linux/types.h>
-#include <linux/futex.h>
-#include <linux/jhash.h>
-#include <linux/mm.h>
-#include <linux/highmem.h>
-#include <linux/uaccess.h>
-#include "lg.h"
-
-/*L:300
- * I/O
- *
- * Getting data in and out of the Guest is quite an art.  There are numerous
- * ways to do it, and they all suck differently.  We try to keep things fairly
- * close to "real" hardware so our Guest's drivers don't look like an alien
- * visitation in the middle of the Linux code, and yet make sure that Guests
- * can talk directly to other Guests, not just the Launcher.
- *
- * To do this, the Guest gives us a key when it binds or sends DMA buffers.
- * The key corresponds to a "physical" address inside the Guest (ie. a virtual
- * address inside the Launcher process).  We don't, however, use this key
- * directly.
- *
- * We want Guests which share memory to be able to DMA to each other: two
- * Launchers can mmap memory the same file, then the Guests can communicate.
- * Fortunately, the futex code provides us with a way to get a "union
- * futex_key" corresponding to the memory lying at a virtual address: if the
- * two processes share memory, the "union futex_key" for that memory will match
- * even if the memory is mapped at different addresses in each.  So we always
- * convert the keys to "union futex_key"s to compare them.
- *
- * Before we dive into this though, we need to look at another set of helper
- * routines used throughout the Host kernel code to access Guest memory.
- :*/
-static struct list_head dma_hash[61];
-
-/* An unfortunate side effect of the Linux double-linked list implementation is
- * that there's no good way to statically initialize an array of linked
- * lists. */
-void lguest_io_init(void)
-{
-	unsigned int i;
-
-	for (i = 0; i < ARRAY_SIZE(dma_hash); i++)
-		INIT_LIST_HEAD(&dma_hash[i]);
-}
-
-/* FIXME: allow multi-page lengths. */
-static int check_dma_list(struct lguest *lg, const struct lguest_dma *dma)
-{
-	unsigned int i;
-
-	for (i = 0; i < LGUEST_MAX_DMA_SECTIONS; i++) {
-		if (!dma->len[i])
-			return 1;
-		if (!lguest_address_ok(lg, dma->addr[i], dma->len[i]))
-			goto kill;
-		if (dma->len[i] > PAGE_SIZE)
-			goto kill;
-		/* We could do over a page, but is it worth it? */
-		if ((dma->addr[i] % PAGE_SIZE) + dma->len[i] > PAGE_SIZE)
-			goto kill;
-	}
-	return 1;
-
-kill:
-	kill_guest(lg, "bad DMA entry: %u@%#lx", dma->len[i], dma->addr[i]);
-	return 0;
-}
-
-/*L:330 This is our hash function, using the wonderful Jenkins hash.
- *
- * The futex key is a union with three parts: an unsigned long word, a pointer,
- * and an int "offset".  We could use jhash_2words() which takes three u32s.
- * (Ok, the hash functions are great: the naming sucks though).
- *
- * It's nice to be portable to 64-bit platforms, so we use the more generic
- * jhash2(), which takes an array of u32, the number of u32s, and an initial
- * u32 to roll in.  This is uglier, but breaks down to almost the same code on
- * 32-bit platforms like this one.
- *
- * We want a position in the array, so we modulo ARRAY_SIZE(dma_hash) (ie. 61).
- */
-static unsigned int hash(const union futex_key *key)
-{
-	return jhash2((u32*)&key->both.word,
-		      (sizeof(key->both.word)+sizeof(key->both.ptr))/4,
-		      key->both.offset)
-		% ARRAY_SIZE(dma_hash);
-}
-
-/* This is a convenience routine to compare two keys.  It's a much bemoaned C
- * weakness that it doesn't allow '==' on structures or unions, so we have to
- * open-code it like this. */
-static inline int key_eq(const union futex_key *a, const union futex_key *b)
-{
-	return (a->both.word == b->both.word
-		&& a->both.ptr == b->both.ptr
-		&& a->both.offset == b->both.offset);
-}
-
-/*L:360 OK, when we need to actually free up a Guest's DMA array we do several
- * things, so we have a convenient function to do it.
- *
- * The caller must hold a read lock on dmainfo owner's current->mm->mmap_sem
- * for the drop_futex_key_refs(). */
-static void unlink_dma(struct lguest_dma_info *dmainfo)
-{
-	/* You locked this too, right? */
-	BUG_ON(!mutex_is_locked(&lguest_lock));
-	/* This is how we know that the entry is free. */
-	dmainfo->interrupt = 0;
-	/* Remove it from the hash table. */
-	list_del(&dmainfo->list);
-	/* Drop the references we were holding (to the inode or mm). */
-	drop_futex_key_refs(&dmainfo->key);
-}
-
-/*L:350 This is the routine which we call when the Guest asks to unregister a
- * DMA array attached to a given key.  Returns true if the array was found. */
-static int unbind_dma(struct lguest *lg,
-		      const union futex_key *key,
-		      unsigned long dmas)
-{
-	int i, ret = 0;
-
-	/* We don't bother with the hash table, just look through all this
-	 * Guest's DMA arrays. */
-	for (i = 0; i < LGUEST_MAX_DMA; i++) {
-		/* In theory it could have more than one array on the same key,
-		 * or one array on multiple keys, so we check both */
-		if (key_eq(key, &lg->dma[i].key) && dmas == lg->dma[i].dmas) {
-			unlink_dma(&lg->dma[i]);
-			ret = 1;
-			break;
-		}
-	}
-	return ret;
-}
-
-/*L:340 BIND_DMA: this is the hypercall which sets up an array of "struct
- * lguest_dma" for receiving I/O.
- *
- * The Guest wants to bind an array of "struct lguest_dma"s to a particular key
- * to receive input.  This only happens when the Guest is setting up a new
- * device, so it doesn't have to be very fast.
- *
- * It returns 1 on a successful registration (it can fail if we hit the limit
- * of registrations for this Guest).
- */
-int bind_dma(struct lguest *lg,
-	     unsigned long ukey, unsigned long dmas, u16 numdmas, u8 interrupt)
-{
-	unsigned int i;
-	int ret = 0;
-	union futex_key key;
-	/* Futex code needs the mmap_sem. */
-	struct rw_semaphore *fshared = &current->mm->mmap_sem;
-
-	/* Invalid interrupt?  (We could kill the guest here). */
-	if (interrupt >= LGUEST_IRQS)
-		return 0;
-
-	/* We need to grab the Big Lguest Lock, because other Guests may be
-	 * trying to look through this Guest's DMAs to send something while
-	 * we're doing this. */
-	mutex_lock(&lguest_lock);
-	down_read(fshared);
-	if (get_futex_key((u32 __user *)ukey, fshared, &key) != 0) {
-		kill_guest(lg, "bad dma key %#lx", ukey);
-		goto unlock;
-	}
-
-	/* We want to keep this key valid once we drop mmap_sem, so we have to
-	 * hold a reference. */
-	get_futex_key_refs(&key);
-
-	/* If the Guest specified an interrupt of 0, that means they want to
-	 * unregister this array of "struct lguest_dma"s. */
-	if (interrupt == 0)
-		ret = unbind_dma(lg, &key, dmas);
-	else {
-		/* Look through this Guest's dma array for an unused entry. */
-		for (i = 0; i < LGUEST_MAX_DMA; i++) {
-			/* If the interrupt is non-zero, the entry is already
-			 * used. */
-			if (lg->dma[i].interrupt)
-				continue;
-
-			/* OK, a free one!  Fill on our details. */
-			lg->dma[i].dmas = dmas;
-			lg->dma[i].num_dmas = numdmas;
-			lg->dma[i].next_dma = 0;
-			lg->dma[i].key = key;
-			lg->dma[i].guestid = lg->guestid;
-			lg->dma[i].interrupt = interrupt;
-
-			/* Now we add it to the hash table: the position
-			 * depends on the futex key that we got. */
-			list_add(&lg->dma[i].list, &dma_hash[hash(&key)]);
-			/* Success! */
-			ret = 1;
-			goto unlock;
-		}
-	}
-	/* If we didn't find a slot to put the key in, drop the reference
-	 * again. */
-	drop_futex_key_refs(&key);
-unlock:
-	/* Unlock and out. */
- 	up_read(fshared);
-	mutex_unlock(&lguest_lock);
-	return ret;
-}
-
-/*L:385 Note that our routines to access a different Guest's memory are called
- * lgread_other() and lgwrite_other(): these names emphasize that they are only
- * used when the Guest is *not* the current Guest.
- *
- * The interface for copying from another process's memory is called
- * access_process_vm(), with a final argument of 0 for a read, and 1 for a
- * write.
- *
- * We need lgread_other() to read the destination Guest's "struct lguest_dma"
- * array. */
-static int lgread_other(struct lguest *lg,
-			void *buf, u32 addr, unsigned bytes)
-{
-	if (!lguest_address_ok(lg, addr, bytes)
-	    || access_process_vm(lg->tsk, addr, buf, bytes, 0) != bytes) {
-		memset(buf, 0, bytes);
-		kill_guest(lg, "bad address in registered DMA struct");
-		return 0;
-	}
-	return 1;
-}
-
-/* "lgwrite()" to another Guest: used to update the destination "used_len" once
- * we've transferred data into the buffer. */
-static int lgwrite_other(struct lguest *lg, u32 addr,
-			 const void *buf, unsigned bytes)
-{
-	if (!lguest_address_ok(lg, addr, bytes)
-	    || (access_process_vm(lg->tsk, addr, (void *)buf, bytes, 1)
-		!= bytes)) {
-		kill_guest(lg, "bad address writing to registered DMA");
-		return 0;
-	}
-	return 1;
-}
-
-/*L:400 This is the generic engine which copies from a source "struct
- * lguest_dma" from this Guest into another Guest's "struct lguest_dma".  The
- * destination Guest's pages have already been mapped, as contained in the
- * pages array.
- *
- * If you're wondering if there's a nice "copy from one process to another"
- * routine, so was I.  But Linux isn't really set up to copy between two
- * unrelated processes, so we have to write it ourselves.
- */
-static u32 copy_data(struct lguest *srclg,
-		     const struct lguest_dma *src,
-		     const struct lguest_dma *dst,
-		     struct page *pages[])
-{
-	unsigned int totlen, si, di, srcoff, dstoff;
-	void *maddr = NULL;
-
-	/* We return the total length transferred. */
-	totlen = 0;
-
-	/* We keep indexes into the source and destination "struct lguest_dma",
-	 * and an offset within each region. */
-	si = di = 0;
-	srcoff = dstoff = 0;
-
-	/* We loop until the source or destination is exhausted. */
-	while (si < LGUEST_MAX_DMA_SECTIONS && src->len[si]
-	       && di < LGUEST_MAX_DMA_SECTIONS && dst->len[di]) {
-		/* We can only transfer the rest of the src buffer, or as much
-		 * as will fit into the destination buffer. */
-		u32 len = min(src->len[si] - srcoff, dst->len[di] - dstoff);
-
-		/* For systems using "highmem" we need to use kmap() to access
-		 * the page we want.  We often use the same page over and over,
-		 * so rather than kmap() it on every loop, we set the maddr
-		 * pointer to NULL when we need to move to the next
-		 * destination page. */
-		if (!maddr)
-			maddr = kmap(pages[di]);
-
-		/* Copy directly from (this Guest's) source address to the
-		 * destination Guest's kmap()ed buffer.  Note that maddr points
-		 * to the start of the page: we need to add the offset of the
-		 * destination address and offset within the buffer. */
-
-		/* FIXME: This is not completely portable.  I looked at
-		 * copy_to_user_page(), and some arch's seem to need special
-		 * flushes.  x86 is fine. */
-		if (copy_from_user(maddr + (dst->addr[di] + dstoff)%PAGE_SIZE,
-				   (void __user *)src->addr[si], len) != 0) {
-			/* If a copy failed, it's the source's fault. */
-			kill_guest(srclg, "bad address in sending DMA");
-			totlen = 0;
-			break;
-		}
-
-		/* Increment the total and src & dst offsets */
-		totlen += len;
-		srcoff += len;
-		dstoff += len;
-
-		/* Presumably we reached the end of the src or dest buffers: */
-		if (srcoff == src->len[si]) {
-			/* Move to the next buffer at offset 0 */
-			si++;
-			srcoff = 0;
-		}
-		if (dstoff == dst->len[di]) {
-			/* We need to unmap that destination page and reset
-			 * maddr ready for the next one. */
-			kunmap(pages[di]);
-			maddr = NULL;
-			di++;
-			dstoff = 0;
-		}
-	}
-
-	/* If we still had a page mapped at the end, unmap now. */
-	if (maddr)
-		kunmap(pages[di]);
-
-	return totlen;
-}
-
-/*L:390 This is how we transfer a "struct lguest_dma" from the source Guest
- * (the current Guest which called SEND_DMA) to another Guest. */
-static u32 do_dma(struct lguest *srclg, const struct lguest_dma *src,
-		  struct lguest *dstlg, const struct lguest_dma *dst)
-{
-	int i;
-	u32 ret;
-	struct page *pages[LGUEST_MAX_DMA_SECTIONS];
-
-	/* We check that both source and destination "struct lguest_dma"s are
-	 * within the bounds of the source and destination Guests */
-	if (!check_dma_list(dstlg, dst) || !check_dma_list(srclg, src))
-		return 0;
-
-	/* We need to map the pages which correspond to each parts of
-	 * destination buffer. */
-	for (i = 0; i < LGUEST_MAX_DMA_SECTIONS; i++) {
-		if (dst->len[i] == 0)
-			break;
-		/* get_user_pages() is a complicated function, especially since
-		 * we only want a single page.  But it works, and returns the
-		 * number of pages.  Note that we're holding the destination's
-		 * mmap_sem, as get_user_pages() requires. */
-		if (get_user_pages(dstlg->tsk, dstlg->mm,
-				   dst->addr[i], 1, 1, 1, pages+i, NULL)
-		    != 1) {
-			/* This means the destination gave us a bogus buffer */
-			kill_guest(dstlg, "Error mapping DMA pages");
-			ret = 0;
-			goto drop_pages;
-		}
-	}
-
-	/* Now copy the data until we run out of src or dst. */
-	ret = copy_data(srclg, src, dst, pages);
-
-drop_pages:
-	while (--i >= 0)
-		put_page(pages[i]);
-	return ret;
-}
-
-/*L:380 Transferring data from one Guest to another is not as simple as I'd
- * like.  We've found the "struct lguest_dma_info" bound to the same address as
- * the send, we need to copy into it.
- *
- * This function returns true if the destination array was empty. */
-static int dma_transfer(struct lguest *srclg,
-			unsigned long udma,
-			struct lguest_dma_info *dst)
-{
-	struct lguest_dma dst_dma, src_dma;
-	struct lguest *dstlg;
-	u32 i, dma = 0;
-
-	/* From the "struct lguest_dma_info" we found in the hash, grab the
-	 * Guest. */
-	dstlg = &lguests[dst->guestid];
-	/* Read in the source "struct lguest_dma" handed to SEND_DMA. */
-	lgread(srclg, &src_dma, udma, sizeof(src_dma));
-
-	/* We need the destination's mmap_sem, and we already hold the source's
-	 * mmap_sem for the futex key lookup.  Normally this would suggest that
-	 * we could deadlock if the destination Guest was trying to send to
-	 * this source Guest at the same time, which is another reason that all
-	 * I/O is done under the big lguest_lock. */
-	down_read(&dstlg->mm->mmap_sem);
-
-	/* Look through the destination DMA array for an available buffer. */
-	for (i = 0; i < dst->num_dmas; i++) {
-		/* We keep a "next_dma" pointer which often helps us avoid
-		 * looking at lots of previously-filled entries. */
-		dma = (dst->next_dma + i) % dst->num_dmas;
-		if (!lgread_other(dstlg, &dst_dma,
-				  dst->dmas + dma * sizeof(struct lguest_dma),
-				  sizeof(dst_dma))) {
-			goto fail;
-		}
-		if (!dst_dma.used_len)
-			break;
-	}
-
-	/* If we found a buffer, we do the actual data copy. */
-	if (i != dst->num_dmas) {
-		unsigned long used_lenp;
-		unsigned int ret;
-
-		ret = do_dma(srclg, &src_dma, dstlg, &dst_dma);
-		/* Put used length in the source "struct lguest_dma"'s used_len
-		 * field.  It's a little tricky to figure out where that is,
-		 * though. */
-		lgwrite_u32(srclg,
-			    udma+offsetof(struct lguest_dma, used_len), ret);
-		/* Tranferring 0 bytes is OK if the source buffer was empty. */
-		if (ret == 0 && src_dma.len[0] != 0)
-			goto fail;
-
-		/* The destination Guest might be running on a different CPU:
-		 * we have to make sure that it will see the "used_len" field
-		 * change to non-zero *after* it sees the data we copied into
-		 * the buffer.  Hence a write memory barrier. */
-		wmb();
-		/* Figuring out where the destination's used_len field for this
-		 * "struct lguest_dma" in the array is also a little ugly. */
-		used_lenp = dst->dmas
-			+ dma * sizeof(struct lguest_dma)
-			+ offsetof(struct lguest_dma, used_len);
-		lgwrite_other(dstlg, used_lenp, &ret, sizeof(ret));
-		/* Move the cursor for next time. */
-		dst->next_dma++;
-	}
- 	up_read(&dstlg->mm->mmap_sem);
-
-	/* We trigger the destination interrupt, even if the destination was
-	 * empty and we didn't transfer anything: this gives them a chance to
-	 * wake up and refill. */
-	set_bit(dst->interrupt, dstlg->irqs_pending);
-	/* Wake up the destination process. */
-	wake_up_process(dstlg->tsk);
-	/* If we passed the last "struct lguest_dma", the receive had no
-	 * buffers left. */
-	return i == dst->num_dmas;
-
-fail:
-	up_read(&dstlg->mm->mmap_sem);
-	return 0;
-}
-
-/*L:370 This is the counter-side to the BIND_DMA hypercall; the SEND_DMA
- * hypercall.  We find out who's listening, and send to them. */
-void send_dma(struct lguest *lg, unsigned long ukey, unsigned long udma)
-{
-	union futex_key key;
-	int empty = 0;
-	struct rw_semaphore *fshared = &current->mm->mmap_sem;
-
-again:
-	mutex_lock(&lguest_lock);
-	down_read(fshared);
-	/* Get the futex key for the key the Guest gave us */
-	if (get_futex_key((u32 __user *)ukey, fshared, &key) != 0) {
-		kill_guest(lg, "bad sending DMA key");
-		goto unlock;
-	}
-	/* Since the key must be a multiple of 4, the futex key uses the lower
-	 * bit of the "offset" field (which would always be 0) to indicate a
-	 * mapping which is shared with other processes (ie. Guests). */
-	if (key.shared.offset & 1) {
-		struct lguest_dma_info *i;
-		/* Look through the hash for other Guests. */
-		list_for_each_entry(i, &dma_hash[hash(&key)], list) {
-			/* Don't send to ourselves. */
-			if (i->guestid == lg->guestid)
-				continue;
-			if (!key_eq(&key, &i->key))
-				continue;
-
-			/* If dma_transfer() tells us the destination has no
-			 * available buffers, we increment "empty". */
-			empty += dma_transfer(lg, udma, i);
-			break;
-		}
-		/* If the destination is empty, we release our locks and
-		 * give the destination Guest a brief chance to restock. */
-		if (empty == 1) {
-			/* Give any recipients one chance to restock. */
-			up_read(&current->mm->mmap_sem);
-			mutex_unlock(&lguest_lock);
-			/* Next time, we won't try again. */
-			empty++;
-			goto again;
-		}
-	} else {
-		/* Private mapping: Guest is sending to its Launcher.  We set
-		 * the "dma_is_pending" flag so that the main loop will exit
-		 * and the Launcher's read() from /dev/lguest will return. */
-		lg->dma_is_pending = 1;
-		lg->pending_dma = udma;
-		lg->pending_key = ukey;
-	}
-unlock:
-	up_read(fshared);
-	mutex_unlock(&lguest_lock);
-}
-/*:*/
-
-void release_all_dma(struct lguest *lg)
-{
-	unsigned int i;
-
-	BUG_ON(!mutex_is_locked(&lguest_lock));
-
-	down_read(&lg->mm->mmap_sem);
-	for (i = 0; i < LGUEST_MAX_DMA; i++) {
-		if (lg->dma[i].interrupt)
-			unlink_dma(&lg->dma[i]);
-	}
-	up_read(&lg->mm->mmap_sem);
-}
-
-/*M:007 We only return a single DMA buffer to the Launcher, but it would be
- * more efficient to return a pointer to the entire array of DMA buffers, which
- * it can cache and choose one whenever it wants.
- *
- * Currently the Launcher uses a write to /dev/lguest, and the return value is
- * the address of the DMA structure with the interrupt number placed in
- * dma->used_len.  If we wanted to return the entire array, we need to return
- * the address, array size and interrupt number: this seems to require an
- * ioctl(). :*/
-
-/*L:320 This routine looks for a DMA buffer registered by the Guest on the
- * given key (using the BIND_DMA hypercall). */
-unsigned long get_dma_buffer(struct lguest *lg,
-			     unsigned long ukey, unsigned long *interrupt)
-{
-	unsigned long ret = 0;
-	union futex_key key;
-	struct lguest_dma_info *i;
-	struct rw_semaphore *fshared = &current->mm->mmap_sem;
-
-	/* Take the Big Lguest Lock to stop other Guests sending this Guest DMA
-	 * at the same time. */
-	mutex_lock(&lguest_lock);
-	/* To match between Guests sharing the same underlying memory we steal
-	 * code from the futex infrastructure.  This requires that we hold the
-	 * "mmap_sem" for our process (the Launcher), and pass it to the futex
-	 * code. */
-	down_read(fshared);
-
-	/* This can fail if it's not a valid address, or if the address is not
-	 * divisible by 4 (the futex code needs that, we don't really). */
-	if (get_futex_key((u32 __user *)ukey, fshared, &key) != 0) {
-		kill_guest(lg, "bad registered DMA buffer");
-		goto unlock;
-	}
-	/* Search the hash table for matching entries (the Launcher can only
-	 * send to its own Guest for the moment, so the entry must be for this
-	 * Guest) */
-	list_for_each_entry(i, &dma_hash[hash(&key)], list) {
-		if (key_eq(&key, &i->key) && i->guestid == lg->guestid) {
-			unsigned int j;
-			/* Look through the registered DMA array for an
-			 * available buffer. */
-			for (j = 0; j < i->num_dmas; j++) {
-				struct lguest_dma dma;
-
-				ret = i->dmas + j * sizeof(struct lguest_dma);
-				lgread(lg, &dma, ret, sizeof(dma));
-				if (dma.used_len == 0)
-					break;
-			}
-			/* Store the interrupt the Guest wants when the buffer
-			 * is used. */
-			*interrupt = i->interrupt;
-			break;
-		}
-	}
-unlock:
-	up_read(fshared);
-	mutex_unlock(&lguest_lock);
-	return ret;
-}
-/*:*/
-
-/*L:410 This really has completed the Launcher.  Not only have we now finished
- * the longest chapter in our journey, but this also means we are over halfway
- * through!
- *
- * Enough prevaricating around the bush: it is time for us to dive into the
- * core of the Host, in "make Host".
- */
diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h
index 64f0abe..d9144be 100644
--- a/drivers/lguest/lg.h
+++ b/drivers/lguest/lg.h
@@ -1,119 +1,25 @@
 #ifndef _LGUEST_H
 #define _LGUEST_H
 
-#include <asm/desc.h>
-
-#define GDT_ENTRY_LGUEST_CS	10
-#define GDT_ENTRY_LGUEST_DS	11
-#define LGUEST_CS		(GDT_ENTRY_LGUEST_CS * 8)
-#define LGUEST_DS		(GDT_ENTRY_LGUEST_DS * 8)
-
 #ifndef __ASSEMBLY__
 #include <linux/types.h>
 #include <linux/init.h>
 #include <linux/stringify.h>
-#include <linux/binfmts.h>
-#include <linux/futex.h>
 #include <linux/lguest.h>
 #include <linux/lguest_launcher.h>
 #include <linux/wait.h>
 #include <linux/err.h>
 #include <asm/semaphore.h>
-#include "irq_vectors.h"
-
-#define GUEST_PL 1
 
-struct lguest_regs
-{
-	/* Manually saved part. */
-	unsigned long ebx, ecx, edx;
-	unsigned long esi, edi, ebp;
-	unsigned long gs;
-	unsigned long eax;
-	unsigned long fs, ds, es;
-	unsigned long trapnum, errcode;
-	/* Trap pushed part */
-	unsigned long eip;
-	unsigned long cs;
-	unsigned long eflags;
-	unsigned long esp;
-	unsigned long ss;
-};
+#include <asm/lguest.h>
 
 void free_pagetables(void);
 int init_pagetables(struct page **switcher_page, unsigned int pages);
 
-/* Full 4G segment descriptors, suitable for CS and DS. */
-#define FULL_EXEC_SEGMENT ((struct desc_struct){0x0000ffff, 0x00cf9b00})
-#define FULL_SEGMENT ((struct desc_struct){0x0000ffff, 0x00cf9300})
-
-struct lguest_dma_info
-{
-	struct list_head list;
-	union futex_key key;
-	unsigned long dmas;
-	u16 next_dma;
-	u16 num_dmas;
-	u16 guestid;
-	u8 interrupt; 	/* 0 when not registered */
-};
-
-/*H:310 The page-table code owes a great debt of gratitude to Andi Kleen.  He
- * reviewed the original code which used "u32" for all page table entries, and
- * insisted that it would be far clearer with explicit typing.  I thought it
- * was overkill, but he was right: it is much clearer than it was before.
- *
- * We have separate types for the Guest's ptes & pgds and the shadow ptes &
- * pgds.  There's already a Linux type for these (pte_t and pgd_t) but they
- * change depending on kernel config options (PAE). */
-
-/* Each entry is identical: lower 12 bits of flags and upper 20 bits for the
- * "page frame number" (0 == first physical page, etc).  They are different
- * types so the compiler will warn us if we mix them improperly. */
-typedef union {
-	struct { unsigned flags:12, pfn:20; };
-	struct { unsigned long val; } raw;
-} spgd_t;
-typedef union {
-	struct { unsigned flags:12, pfn:20; };
-	struct { unsigned long val; } raw;
-} spte_t;
-typedef union {
-	struct { unsigned flags:12, pfn:20; };
-	struct { unsigned long val; } raw;
-} gpgd_t;
-typedef union {
-	struct { unsigned flags:12, pfn:20; };
-	struct { unsigned long val; } raw;
-} gpte_t;
-
-/* We have two convenient macros to convert a "raw" value as handed to us by
- * the Guest into the correct Guest PGD or PTE type. */
-#define mkgpte(_val) ((gpte_t){.raw.val = _val})
-#define mkgpgd(_val) ((gpgd_t){.raw.val = _val})
-/*:*/
-
 struct pgdir
 {
-	unsigned long cr3;
-	spgd_t *pgdir;
-};
-
-/* This is a guest-specific page (mapped ro) into the guest. */
-struct lguest_ro_state
-{
-	/* Host information we need to restore when we switch back. */
-	u32 host_cr3;
-	struct Xgt_desc_struct host_idt_desc;
-	struct Xgt_desc_struct host_gdt_desc;
-	u32 host_sp;
-
-	/* Fields which are used when guest is running. */
-	struct Xgt_desc_struct guest_idt_desc;
-	struct Xgt_desc_struct guest_gdt_desc;
-	struct i386_hw_tss guest_tss;
-	struct desc_struct guest_idt[IDT_ENTRIES];
-	struct desc_struct guest_gdt[GDT_ENTRIES];
+	unsigned long gpgdir;
+	pgd_t *pgdir;
 };
 
 /* We have two pages shared with guests, per cpu.  */
@@ -141,9 +47,11 @@ struct lguest
 	struct lguest_data __user *lguest_data;
 	struct task_struct *tsk;
 	struct mm_struct *mm; 	/* == tsk->mm, but that becomes NULL on exit */
-	u16 guestid;
 	u32 pfn_limit;
-	u32 page_offset;
+	/* This provides the offset to the base of guest-physical
+	 * memory in the Launcher. */
+	void __user *mem_base;
+	unsigned long kernel_address;
 	u32 cr2;
 	int halted;
 	int ts;
@@ -151,6 +59,9 @@ struct lguest
 	u32 esp1;
 	u8 ss1;
 
+	/* If a hypercall was asked for, this points to the arguments. */
+	struct hcall_args *hcall;
+
 	/* Do we need to stop what we're doing and return to userspace? */
 	int break_out;
 	wait_queue_head_t break_wq;
@@ -167,24 +78,15 @@ struct lguest
 	struct task_struct *wake;
 
 	unsigned long noirq_start, noirq_end;
-	int dma_is_pending;
-	unsigned long pending_dma; /* struct lguest_dma */
-	unsigned long pending_key; /* address they're sending to */
+	unsigned long pending_notify; /* pfn from LHCALL_NOTIFY */
 
 	unsigned int stack_pages;
 	u32 tsc_khz;
 
-	struct lguest_dma_info dma[LGUEST_MAX_DMA];
-
 	/* Dead? */
 	const char *dead;
 
-	/* The GDT entries copied into lguest_ro_state when running. */
-	struct desc_struct gdt[GDT_ENTRIES];
-
-	/* The IDT entries: some copied into lguest_ro_state when running. */
-	struct desc_struct idt[FIRST_EXTERNAL_VECTOR+LGUEST_IRQS];
-	struct desc_struct syscall_idt;
+	struct lguest_arch arch;
 
 	/* Virtual clock device */
 	struct hrtimer hrt;
@@ -193,19 +95,38 @@ struct lguest
 	DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
 };
 
-extern struct lguest lguests[];
 extern struct mutex lguest_lock;
 
 /* core.c: */
-u32 lgread_u32(struct lguest *lg, unsigned long addr);
-void lgwrite_u32(struct lguest *lg, unsigned long addr, u32 val);
-void lgread(struct lguest *lg, void *buf, unsigned long addr, unsigned len);
-void lgwrite(struct lguest *lg, unsigned long, const void *buf, unsigned len);
-int find_free_guest(void);
 int lguest_address_ok(const struct lguest *lg,
 		      unsigned long addr, unsigned long len);
+void __lgread(struct lguest *, void *, unsigned long, unsigned);
+void __lgwrite(struct lguest *, unsigned long, const void *, unsigned);
+
+/*L:306 Using memory-copy operations like that is usually inconvient, so we
+ * have the following helper macros which read and write a specific type (often
+ * an unsigned long).
+ *
+ * This reads into a variable of the given type then returns that. */
+#define lgread(lg, addr, type)						\
+	({ type _v; __lgread((lg), &_v, (addr), sizeof(_v)); _v; })
+
+/* This checks that the variable is of the given type, then writes it out. */
+#define lgwrite(lg, addr, type, val)				\
+	do {							\
+		typecheck(type, val);				\
+		__lgwrite((lg), (addr), &(val), sizeof(val));	\
+	} while(0)
+/* (end of memory access helper routines) :*/
+
 int run_guest(struct lguest *lg, unsigned long __user *user);
 
+/* Helper macros to obtain the first 12 or the last 20 bits, this is only the
+ * first step in the migration to the kernel types.  pte_pfn is already defined
+ * in the kernel. */
+#define pgd_flags(x)	(pgd_val(x) & ~PAGE_MASK)
+#define pte_flags(x)	(pte_val(x) & ~PAGE_MASK)
+#define pgd_pfn(x)	(pgd_val(x) >> PAGE_SHIFT)
 
 /* interrupts_and_traps.c: */
 void maybe_do_interrupt(struct lguest *lg);
@@ -219,6 +140,9 @@ void copy_traps(const struct lguest *lg, struct desc_struct *idt,
 		const unsigned long *def);
 void guest_set_clockevent(struct lguest *lg, unsigned long delta);
 void init_clockdev(struct lguest *lg);
+bool check_syscall_vector(struct lguest *lg);
+int init_interrupts(void);
+void free_interrupts(void);
 
 /* segments.c: */
 void setup_default_gdt_entries(struct lguest_ro_state *state);
@@ -232,28 +156,33 @@ void copy_gdt_tls(const struct lguest *lg, struct desc_struct *gdt);
 int init_guest_pagetable(struct lguest *lg, unsigned long pgtable);
 void free_guest_pagetable(struct lguest *lg);
 void guest_new_pagetable(struct lguest *lg, unsigned long pgtable);
-void guest_set_pmd(struct lguest *lg, unsigned long cr3, u32 i);
+void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
 void guest_pagetable_clear_all(struct lguest *lg);
 void guest_pagetable_flush_user(struct lguest *lg);
-void guest_set_pte(struct lguest *lg, unsigned long cr3,
-		   unsigned long vaddr, gpte_t val);
+void guest_set_pte(struct lguest *lg, unsigned long gpgdir,
+		   unsigned long vaddr, pte_t val);
 void map_switcher_in_guest(struct lguest *lg, struct lguest_pages *pages);
 int demand_page(struct lguest *info, unsigned long cr2, int errcode);
 void pin_page(struct lguest *lg, unsigned long vaddr);
+unsigned long guest_pa(struct lguest *lg, unsigned long vaddr);
+void page_table_guest_data_init(struct lguest *lg);
+
+/* <arch>/core.c: */
+void lguest_arch_host_init(void);
+void lguest_arch_host_fini(void);
+void lguest_arch_run_guest(struct lguest *lg);
+void lguest_arch_handle_trap(struct lguest *lg);
+int lguest_arch_init_hypercalls(struct lguest *lg);
+int lguest_arch_do_hcall(struct lguest *lg, struct hcall_args *args);
+void lguest_arch_setup_regs(struct lguest *lg, unsigned long start);
+
+/* <arch>/switcher.S: */
+extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];
 
 /* lguest_user.c: */
 int lguest_device_init(void);
 void lguest_device_remove(void);
 
-/* io.c: */
-void lguest_io_init(void);
-int bind_dma(struct lguest *lg,
-	     unsigned long key, unsigned long udma, u16 numdmas, u8 interrupt);
-void send_dma(struct lguest *info, unsigned long key, unsigned long udma);
-void release_all_dma(struct lguest *lg);
-unsigned long get_dma_buffer(struct lguest *lg, unsigned long key,
-			     unsigned long *interrupt);
-
 /* hypercalls.c: */
 void do_hypercalls(struct lguest *lg);
 void write_timestamp(struct lguest *lg);
@@ -292,9 +221,5 @@ do {								\
 } while(0)
 /* (End of aside) :*/
 
-static inline unsigned long guest_pa(struct lguest *lg, unsigned long vaddr)
-{
-	return vaddr - lg->page_offset;
-}
 #endif	/* __ASSEMBLY__ */
 #endif	/* _LGUEST_H */
diff --git a/drivers/lguest/lguest.c b/drivers/lguest/lguest.c
deleted file mode 100644
index 3ba337d..0000000
--- a/drivers/lguest/lguest.c
+++ /dev/null
@@ -1,1108 +0,0 @@
-/*P:010
- * A hypervisor allows multiple Operating Systems to run on a single machine.
- * To quote David Wheeler: "Any problem in computer science can be solved with
- * another layer of indirection."
- *
- * We keep things simple in two ways.  First, we start with a normal Linux
- * kernel and insert a module (lg.ko) which allows us to run other Linux
- * kernels the same way we'd run processes.  We call the first kernel the Host,
- * and the others the Guests.  The program which sets up and configures Guests
- * (such as the example in Documentation/lguest/lguest.c) is called the
- * Launcher.
- *
- * Secondly, we only run specially modified Guests, not normal kernels.  When
- * you set CONFIG_LGUEST to 'y' or 'm', this automatically sets
- * CONFIG_LGUEST_GUEST=y, which compiles this file into the kernel so it knows
- * how to be a Guest.  This means that you can use the same kernel you boot
- * normally (ie. as a Host) as a Guest.
- *
- * These Guests know that they cannot do privileged operations, such as disable
- * interrupts, and that they have to ask the Host to do such things explicitly.
- * This file consists of all the replacements for such low-level native
- * hardware operations: these special Guest versions call the Host.
- *
- * So how does the kernel know it's a Guest?  The Guest starts at a special
- * entry point marked with a magic string, which sets up a few things then
- * calls here.  We replace the native functions various "paravirt" structures
- * with our Guest versions, then boot like normal. :*/
-
-/*
- * Copyright (C) 2006, Rusty Russell <rusty@rustcorp.com.au> IBM Corporation.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT.  See the GNU General Public License for more
- * details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-#include <linux/kernel.h>
-#include <linux/start_kernel.h>
-#include <linux/string.h>
-#include <linux/console.h>
-#include <linux/screen_info.h>
-#include <linux/irq.h>
-#include <linux/interrupt.h>
-#include <linux/clocksource.h>
-#include <linux/clockchips.h>
-#include <linux/lguest.h>
-#include <linux/lguest_launcher.h>
-#include <linux/lguest_bus.h>
-#include <asm/paravirt.h>
-#include <asm/param.h>
-#include <asm/page.h>
-#include <asm/pgtable.h>
-#include <asm/desc.h>
-#include <asm/setup.h>
-#include <asm/e820.h>
-#include <asm/mce.h>
-#include <asm/io.h>
-
-/*G:010 Welcome to the Guest!
- *
- * The Guest in our tale is a simple creature: identical to the Host but
- * behaving in simplified but equivalent ways.  In particular, the Guest is the
- * same kernel as the Host (or at least, built from the same source code). :*/
-
-/* Declarations for definitions in lguest_guest.S */
-extern char lguest_noirq_start[], lguest_noirq_end[];
-extern const char lgstart_cli[], lgend_cli[];
-extern const char lgstart_sti[], lgend_sti[];
-extern const char lgstart_popf[], lgend_popf[];
-extern const char lgstart_pushf[], lgend_pushf[];
-extern const char lgstart_iret[], lgend_iret[];
-extern void lguest_iret(void);
-
-struct lguest_data lguest_data = {
-	.hcall_status = { [0 ... LHCALL_RING_SIZE-1] = 0xFF },
-	.noirq_start = (u32)lguest_noirq_start,
-	.noirq_end = (u32)lguest_noirq_end,
-	.blocked_interrupts = { 1 }, /* Block timer interrupts */
-};
-struct lguest_device_desc *lguest_devices;
-static cycle_t clock_base;
-
-/*G:035 Notice the lazy_hcall() above, rather than hcall().  This is our first
- * real optimization trick!
- *
- * When lazy_mode is set, it means we're allowed to defer all hypercalls and do
- * them as a batch when lazy_mode is eventually turned off.  Because hypercalls
- * are reasonably expensive, batching them up makes sense.  For example, a
- * large mmap might update dozens of page table entries: that code calls
- * paravirt_enter_lazy_mmu(), does the dozen updates, then calls
- * lguest_leave_lazy_mode().
- *
- * So, when we're in lazy mode, we call async_hypercall() to store the call for
- * future processing.  When lazy mode is turned off we issue a hypercall to
- * flush the stored calls.
- */
-static void lguest_leave_lazy_mode(void)
-{
-	paravirt_leave_lazy(paravirt_get_lazy_mode());
-	hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0);
-}
-
-static void lazy_hcall(unsigned long call,
-		       unsigned long arg1,
-		       unsigned long arg2,
-		       unsigned long arg3)
-{
-	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
-		hcall(call, arg1, arg2, arg3);
-	else
-		async_hcall(call, arg1, arg2, arg3);
-}
-
-/* async_hcall() is pretty simple: I'm quite proud of it really.  We have a
- * ring buffer of stored hypercalls which the Host will run though next time we
- * do a normal hypercall.  Each entry in the ring has 4 slots for the hypercall
- * arguments, and a "hcall_status" word which is 0 if the call is ready to go,
- * and 255 once the Host has finished with it.
- *
- * If we come around to a slot which hasn't been finished, then the table is
- * full and we just make the hypercall directly.  This has the nice side
- * effect of causing the Host to run all the stored calls in the ring buffer
- * which empties it for next time! */
-void async_hcall(unsigned long call,
-		 unsigned long arg1, unsigned long arg2, unsigned long arg3)
-{
-	/* Note: This code assumes we're uniprocessor. */
-	static unsigned int next_call;
-	unsigned long flags;
-
-	/* Disable interrupts if not already disabled: we don't want an
-	 * interrupt handler making a hypercall while we're already doing
-	 * one! */
-	local_irq_save(flags);
-	if (lguest_data.hcall_status[next_call] != 0xFF) {
-		/* Table full, so do normal hcall which will flush table. */
-		hcall(call, arg1, arg2, arg3);
-	} else {
-		lguest_data.hcalls[next_call].eax = call;
-		lguest_data.hcalls[next_call].edx = arg1;
-		lguest_data.hcalls[next_call].ebx = arg2;
-		lguest_data.hcalls[next_call].ecx = arg3;
-		/* Arguments must all be written before we mark it to go */
-		wmb();
-		lguest_data.hcall_status[next_call] = 0;
-		if (++next_call == LHCALL_RING_SIZE)
-			next_call = 0;
-	}
-	local_irq_restore(flags);
-}
-/*:*/
-
-/* Wrappers for the SEND_DMA and BIND_DMA hypercalls.  This is mainly because
- * Jeff Garzik complained that __pa() should never appear in drivers, and this
- * helps remove most of them.   But also, it wraps some ugliness. */
-void lguest_send_dma(unsigned long key, struct lguest_dma *dma)
-{
-	/* The hcall might not write this if something goes wrong */
-	dma->used_len = 0;
-	hcall(LHCALL_SEND_DMA, key, __pa(dma), 0);
-}
-
-int lguest_bind_dma(unsigned long key, struct lguest_dma *dmas,
-		    unsigned int num, u8 irq)
-{
-	/* This is the only hypercall which actually wants 5 arguments, and we
-	 * only support 4.  Fortunately the interrupt number is always less
-	 * than 256, so we can pack it with the number of dmas in the final
-	 * argument.  */
-	if (!hcall(LHCALL_BIND_DMA, key, __pa(dmas), (num << 8) | irq))
-		return -ENOMEM;
-	return 0;
-}
-
-/* Unbinding is the same hypercall as binding, but with 0 num & irq. */
-void lguest_unbind_dma(unsigned long key, struct lguest_dma *dmas)
-{
-	hcall(LHCALL_BIND_DMA, key, __pa(dmas), 0);
-}
-
-/* For guests, device memory can be used as normal memory, so we cast away the
- * __iomem to quieten sparse. */
-void *lguest_map(unsigned long phys_addr, unsigned long pages)
-{
-	return (__force void *)ioremap(phys_addr, PAGE_SIZE*pages);
-}
-
-void lguest_unmap(void *addr)
-{
-	iounmap((__force void __iomem *)addr);
-}
-
-/*G:033
- * Here are our first native-instruction replacements: four functions for
- * interrupt control.
- *
- * The simplest way of implementing these would be to have "turn interrupts
- * off" and "turn interrupts on" hypercalls.  Unfortunately, this is too slow:
- * these are by far the most commonly called functions of those we override.
- *
- * So instead we keep an "irq_enabled" field inside our "struct lguest_data",
- * which the Guest can update with a single instruction.  The Host knows to
- * check there when it wants to deliver an interrupt.
- */
-
-/* save_flags() is expected to return the processor state (ie. "eflags").  The
- * eflags word contains all kind of stuff, but in practice Linux only cares
- * about the interrupt flag.  Our "save_flags()" just returns that. */
-static unsigned long save_fl(void)
-{
-	return lguest_data.irq_enabled;
-}
-
-/* "restore_flags" just sets the flags back to the value given. */
-static void restore_fl(unsigned long flags)
-{
-	lguest_data.irq_enabled = flags;
-}
-
-/* Interrupts go off... */
-static void irq_disable(void)
-{
-	lguest_data.irq_enabled = 0;
-}
-
-/* Interrupts go on... */
-static void irq_enable(void)
-{
-	lguest_data.irq_enabled = X86_EFLAGS_IF;
-}
-/*:*/
-/*M:003 Note that we don't check for outstanding interrupts when we re-enable
- * them (or when we unmask an interrupt).  This seems to work for the moment,
- * since interrupts are rare and we'll just get the interrupt on the next timer
- * tick, but when we turn on CONFIG_NO_HZ, we should revisit this.  One way
- * would be to put the "irq_enabled" field in a page by itself, and have the
- * Host write-protect it when an interrupt comes in when irqs are disabled.
- * There will then be a page fault as soon as interrupts are re-enabled. :*/
-
-/*G:034
- * The Interrupt Descriptor Table (IDT).
- *
- * The IDT tells the processor what to do when an interrupt comes in.  Each
- * entry in the table is a 64-bit descriptor: this holds the privilege level,
- * address of the handler, and... well, who cares?  The Guest just asks the
- * Host to make the change anyway, because the Host controls the real IDT.
- */
-static void lguest_write_idt_entry(struct desc_struct *dt,
-				   int entrynum, u32 low, u32 high)
-{
-	/* Keep the local copy up to date. */
-	write_dt_entry(dt, entrynum, low, high);
-	/* Tell Host about this new entry. */
-	hcall(LHCALL_LOAD_IDT_ENTRY, entrynum, low, high);
-}
-
-/* Changing to a different IDT is very rare: we keep the IDT up-to-date every
- * time it is written, so we can simply loop through all entries and tell the
- * Host about them. */
-static void lguest_load_idt(const struct Xgt_desc_struct *desc)
-{
-	unsigned int i;
-	struct desc_struct *idt = (void *)desc->address;
-
-	for (i = 0; i < (desc->size+1)/8; i++)
-		hcall(LHCALL_LOAD_IDT_ENTRY, i, idt[i].a, idt[i].b);
-}
-
-/*
- * The Global Descriptor Table.
- *
- * The Intel architecture defines another table, called the Global Descriptor
- * Table (GDT).  You tell the CPU where it is (and its size) using the "lgdt"
- * instruction, and then several other instructions refer to entries in the
- * table.  There are three entries which the Switcher needs, so the Host simply
- * controls the entire thing and the Guest asks it to make changes using the
- * LOAD_GDT hypercall.
- *
- * This is the opposite of the IDT code where we have a LOAD_IDT_ENTRY
- * hypercall and use that repeatedly to load a new IDT.  I don't think it
- * really matters, but wouldn't it be nice if they were the same?
- */
-static void lguest_load_gdt(const struct Xgt_desc_struct *desc)
-{
-	BUG_ON((desc->size+1)/8 != GDT_ENTRIES);
-	hcall(LHCALL_LOAD_GDT, __pa(desc->address), GDT_ENTRIES, 0);
-}
-
-/* For a single GDT entry which changes, we do the lazy thing: alter our GDT,
- * then tell the Host to reload the entire thing.  This operation is so rare
- * that this naive implementation is reasonable. */
-static void lguest_write_gdt_entry(struct desc_struct *dt,
-				   int entrynum, u32 low, u32 high)
-{
-	write_dt_entry(dt, entrynum, low, high);
-	hcall(LHCALL_LOAD_GDT, __pa(dt), GDT_ENTRIES, 0);
-}
-
-/* OK, I lied.  There are three "thread local storage" GDT entries which change
- * on every context switch (these three entries are how glibc implements
- * __thread variables).  So we have a hypercall specifically for this case. */
-static void lguest_load_tls(struct thread_struct *t, unsigned int cpu)
-{
-	/* There's one problem which normal hardware doesn't have: the Host
-	 * can't handle us removing entries we're currently using.  So we clear
-	 * the GS register here: if it's needed it'll be reloaded anyway. */
-	loadsegment(gs, 0);
-	lazy_hcall(LHCALL_LOAD_TLS, __pa(&t->tls_array), cpu, 0);
-}
-
-/*G:038 That's enough excitement for now, back to ploughing through each of
- * the different pv_ops structures (we're about 1/3 of the way through).
- *
- * This is the Local Descriptor Table, another weird Intel thingy.  Linux only
- * uses this for some strange applications like Wine.  We don't do anything
- * here, so they'll get an informative and friendly Segmentation Fault. */
-static void lguest_set_ldt(const void *addr, unsigned entries)
-{
-}
-
-/* This loads a GDT entry into the "Task Register": that entry points to a
- * structure called the Task State Segment.  Some comments scattered though the
- * kernel code indicate that this used for task switching in ages past, along
- * with blood sacrifice and astrology.
- *
- * Now there's nothing interesting in here that we don't get told elsewhere.
- * But the native version uses the "ltr" instruction, which makes the Host
- * complain to the Guest about a Segmentation Fault and it'll oops.  So we
- * override the native version with a do-nothing version. */
-static void lguest_load_tr_desc(void)
-{
-}
-
-/* The "cpuid" instruction is a way of querying both the CPU identity
- * (manufacturer, model, etc) and its features.  It was introduced before the
- * Pentium in 1993 and keeps getting extended by both Intel and AMD.  As you
- * might imagine, after a decade and a half this treatment, it is now a giant
- * ball of hair.  Its entry in the current Intel manual runs to 28 pages.
- *
- * This instruction even it has its own Wikipedia entry.  The Wikipedia entry
- * has been translated into 4 languages.  I am not making this up!
- *
- * We could get funky here and identify ourselves as "GenuineLguest", but
- * instead we just use the real "cpuid" instruction.  Then I pretty much turned
- * off feature bits until the Guest booted.  (Don't say that: you'll damage
- * lguest sales!)  Shut up, inner voice!  (Hey, just pointing out that this is
- * hardly future proof.)  Noone's listening!  They don't like you anyway,
- * parenthetic weirdo!
- *
- * Replacing the cpuid so we can turn features off is great for the kernel, but
- * anyone (including userspace) can just use the raw "cpuid" instruction and
- * the Host won't even notice since it isn't privileged.  So we try not to get
- * too worked up about it. */
-static void lguest_cpuid(unsigned int *eax, unsigned int *ebx,
-			 unsigned int *ecx, unsigned int *edx)
-{
-	int function = *eax;
-
-	native_cpuid(eax, ebx, ecx, edx);
-	switch (function) {
-	case 1:	/* Basic feature request. */
-		/* We only allow kernel to see SSE3, CMPXCHG16B and SSSE3 */
-		*ecx &= 0x00002201;
-		/* SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, FPU. */
-		*edx &= 0x07808101;
-		/* The Host can do a nice optimization if it knows that the
-		 * kernel mappings (addresses above 0xC0000000 or whatever
-		 * PAGE_OFFSET is set to) haven't changed.  But Linux calls
-		 * flush_tlb_user() for both user and kernel mappings unless
-		 * the Page Global Enable (PGE) feature bit is set. */
-		*edx |= 0x00002000;
-		break;
-	case 0x80000000:
-		/* Futureproof this a little: if they ask how much extended
-		 * processor information there is, limit it to known fields. */
-		if (*eax > 0x80000008)
-			*eax = 0x80000008;
-		break;
-	}
-}
-
-/* Intel has four control registers, imaginatively named cr0, cr2, cr3 and cr4.
- * I assume there's a cr1, but it hasn't bothered us yet, so we'll not bother
- * it.  The Host needs to know when the Guest wants to change them, so we have
- * a whole series of functions like read_cr0() and write_cr0().
- *
- * We start with CR0.  CR0 allows you to turn on and off all kinds of basic
- * features, but Linux only really cares about one: the horrifically-named Task
- * Switched (TS) bit at bit 3 (ie. 8)
- *
- * What does the TS bit do?  Well, it causes the CPU to trap (interrupt 7) if
- * the floating point unit is used.  Which allows us to restore FPU state
- * lazily after a task switch, and Linux uses that gratefully, but wouldn't a
- * name like "FPUTRAP bit" be a little less cryptic?
- *
- * We store cr0 (and cr3) locally, because the Host never changes it.  The
- * Guest sometimes wants to read it and we'd prefer not to bother the Host
- * unnecessarily. */
-static unsigned long current_cr0, current_cr3;
-static void lguest_write_cr0(unsigned long val)
-{
-	/* 8 == TS bit. */
-	lazy_hcall(LHCALL_TS, val & 8, 0, 0);
-	current_cr0 = val;
-}
-
-static unsigned long lguest_read_cr0(void)
-{
-	return current_cr0;
-}
-
-/* Intel provided a special instruction to clear the TS bit for people too cool
- * to use write_cr0() to do it.  This "clts" instruction is faster, because all
- * the vowels have been optimized out. */
-static void lguest_clts(void)
-{
-	lazy_hcall(LHCALL_TS, 0, 0, 0);
-	current_cr0 &= ~8U;
-}
-
-/* CR2 is the virtual address of the last page fault, which the Guest only ever
- * reads.  The Host kindly writes this into our "struct lguest_data", so we
- * just read it out of there. */
-static unsigned long lguest_read_cr2(void)
-{
-	return lguest_data.cr2;
-}
-
-/* CR3 is the current toplevel pagetable page: the principle is the same as
- * cr0.  Keep a local copy, and tell the Host when it changes. */
-static void lguest_write_cr3(unsigned long cr3)
-{
-	lazy_hcall(LHCALL_NEW_PGTABLE, cr3, 0, 0);
-	current_cr3 = cr3;
-}
-
-static unsigned long lguest_read_cr3(void)
-{
-	return current_cr3;
-}
-
-/* CR4 is used to enable and disable PGE, but we don't care. */
-static unsigned long lguest_read_cr4(void)
-{
-	return 0;
-}
-
-static void lguest_write_cr4(unsigned long val)
-{
-}
-
-/*
- * Page Table Handling.
- *
- * Now would be a good time to take a rest and grab a coffee or similarly
- * relaxing stimulant.  The easy parts are behind us, and the trek gradually
- * winds uphill from here.
- *
- * Quick refresher: memory is divided into "pages" of 4096 bytes each.  The CPU
- * maps virtual addresses to physical addresses using "page tables".  We could
- * use one huge index of 1 million entries: each address is 4 bytes, so that's
- * 1024 pages just to hold the page tables.   But since most virtual addresses
- * are unused, we use a two level index which saves space.  The CR3 register
- * contains the physical address of the top level "page directory" page, which
- * contains physical addresses of up to 1024 second-level pages.  Each of these
- * second level pages contains up to 1024 physical addresses of actual pages,
- * or Page Table Entries (PTEs).
- *
- * Here's a diagram, where arrows indicate physical addresses:
- *
- * CR3 ---> +---------+
- *	    |  	   --------->+---------+
- *	    |	      |	     | PADDR1  |
- *	  Top-level   |	     | PADDR2  |
- *	  (PMD) page  |	     | 	       |
- *	    |	      |	   Lower-level |
- *	    |	      |	   (PTE) page  |
- *	    |	      |	     |	       |
- *	      ....    	     	 ....
- *
- * So to convert a virtual address to a physical address, we look up the top
- * level, which points us to the second level, which gives us the physical
- * address of that page.  If the top level entry was not present, or the second
- * level entry was not present, then the virtual address is invalid (we
- * say "the page was not mapped").
- *
- * Put another way, a 32-bit virtual address is divided up like so:
- *
- *  1 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
- * |<---- 10 bits ---->|<---- 10 bits ---->|<------ 12 bits ------>|
- *    Index into top     Index into second      Offset within page
- *  page directory page    pagetable page
- *
- * The kernel spends a lot of time changing both the top-level page directory
- * and lower-level pagetable pages.  The Guest doesn't know physical addresses,
- * so while it maintains these page tables exactly like normal, it also needs
- * to keep the Host informed whenever it makes a change: the Host will create
- * the real page tables based on the Guests'.
- */
-
-/* The Guest calls this to set a second-level entry (pte), ie. to map a page
- * into a process' address space.  We set the entry then tell the Host the
- * toplevel and address this corresponds to.  The Guest uses one pagetable per
- * process, so we need to tell the Host which one we're changing (mm->pgd). */
-static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
-			      pte_t *ptep, pte_t pteval)
-{
-	*ptep = pteval;
-	lazy_hcall(LHCALL_SET_PTE, __pa(mm->pgd), addr, pteval.pte_low);
-}
-
-/* The Guest calls this to set a top-level entry.  Again, we set the entry then
- * tell the Host which top-level page we changed, and the index of the entry we
- * changed. */
-static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
-{
-	*pmdp = pmdval;
-	lazy_hcall(LHCALL_SET_PMD, __pa(pmdp)&PAGE_MASK,
-		   (__pa(pmdp)&(PAGE_SIZE-1))/4, 0);
-}
-
-/* There are a couple of legacy places where the kernel sets a PTE, but we
- * don't know the top level any more.  This is useless for us, since we don't
- * know which pagetable is changing or what address, so we just tell the Host
- * to forget all of them.  Fortunately, this is very rare.
- *
- * ... except in early boot when the kernel sets up the initial pagetables,
- * which makes booting astonishingly slow.  So we don't even tell the Host
- * anything changed until we've done the first page table switch.
- */
-static void lguest_set_pte(pte_t *ptep, pte_t pteval)
-{
-	*ptep = pteval;
-	/* Don't bother with hypercall before initial setup. */
-	if (current_cr3)
-		lazy_hcall(LHCALL_FLUSH_TLB, 1, 0, 0);
-}
-
-/* Unfortunately for Lguest, the pv_mmu_ops for page tables were based on
- * native page table operations.  On native hardware you can set a new page
- * table entry whenever you want, but if you want to remove one you have to do
- * a TLB flush (a TLB is a little cache of page table entries kept by the CPU).
- *
- * So the lguest_set_pte_at() and lguest_set_pmd() functions above are only
- * called when a valid entry is written, not when it's removed (ie. marked not
- * present).  Instead, this is where we come when the Guest wants to remove a
- * page table entry: we tell the Host to set that entry to 0 (ie. the present
- * bit is zero). */
-static void lguest_flush_tlb_single(unsigned long addr)
-{
-	/* Simply set it to zero: if it was not, it will fault back in. */
-	lazy_hcall(LHCALL_SET_PTE, current_cr3, addr, 0);
-}
-
-/* This is what happens after the Guest has removed a large number of entries.
- * This tells the Host that any of the page table entries for userspace might
- * have changed, ie. virtual addresses below PAGE_OFFSET. */
-static void lguest_flush_tlb_user(void)
-{
-	lazy_hcall(LHCALL_FLUSH_TLB, 0, 0, 0);
-}
-
-/* This is called when the kernel page tables have changed.  That's not very
- * common (unless the Guest is using highmem, which makes the Guest extremely
- * slow), so it's worth separating this from the user flushing above. */
-static void lguest_flush_tlb_kernel(void)
-{
-	lazy_hcall(LHCALL_FLUSH_TLB, 1, 0, 0);
-}
-
-/*
- * The Unadvanced Programmable Interrupt Controller.
- *
- * This is an attempt to implement the simplest possible interrupt controller.
- * I spent some time looking though routines like set_irq_chip_and_handler,
- * set_irq_chip_and_handler_name, set_irq_chip_data and set_phasers_to_stun and
- * I *think* this is as simple as it gets.
- *
- * We can tell the Host what interrupts we want blocked ready for using the
- * lguest_data.interrupts bitmap, so disabling (aka "masking") them is as
- * simple as setting a bit.  We don't actually "ack" interrupts as such, we
- * just mask and unmask them.  I wonder if we should be cleverer?
- */
-static void disable_lguest_irq(unsigned int irq)
-{
-	set_bit(irq, lguest_data.blocked_interrupts);
-}
-
-static void enable_lguest_irq(unsigned int irq)
-{
-	clear_bit(irq, lguest_data.blocked_interrupts);
-}
-
-/* This structure describes the lguest IRQ controller. */
-static struct irq_chip lguest_irq_controller = {
-	.name		= "lguest",
-	.mask		= disable_lguest_irq,
-	.mask_ack	= disable_lguest_irq,
-	.unmask		= enable_lguest_irq,
-};
-
-/* This sets up the Interrupt Descriptor Table (IDT) entry for each hardware
- * interrupt (except 128, which is used for system calls), and then tells the
- * Linux infrastructure that each interrupt is controlled by our level-based
- * lguest interrupt controller. */
-static void __init lguest_init_IRQ(void)
-{
-	unsigned int i;
-
-	for (i = 0; i < LGUEST_IRQS; i++) {
-		int vector = FIRST_EXTERNAL_VECTOR + i;
-		if (vector != SYSCALL_VECTOR) {
-			set_intr_gate(vector, interrupt[i]);
-			set_irq_chip_and_handler(i, &lguest_irq_controller,
-						 handle_level_irq);
-		}
-	}
-	/* This call is required to set up for 4k stacks, where we have
-	 * separate stacks for hard and soft interrupts. */
-	irq_ctx_init(smp_processor_id());
-}
-
-/*
- * Time.
- *
- * It would be far better for everyone if the Guest had its own clock, but
- * until then the Host gives us the time on every interrupt.
- */
-static unsigned long lguest_get_wallclock(void)
-{
-	return lguest_data.time.tv_sec;
-}
-
-static cycle_t lguest_clock_read(void)
-{
-	unsigned long sec, nsec;
-
-	/* If the Host tells the TSC speed, we can trust that. */
-	if (lguest_data.tsc_khz)
-		return native_read_tsc();
-
-	/* If we can't use the TSC, we read the time value written by the Host.
-	 * Since it's in two parts (seconds and nanoseconds), we risk reading
-	 * it just as it's changing from 99 & 0.999999999 to 100 and 0, and
-	 * getting 99 and 0.  As Linux tends to come apart under the stress of
-	 * time travel, we must be careful: */
-	do {
-		/* First we read the seconds part. */
-		sec = lguest_data.time.tv_sec;
-		/* This read memory barrier tells the compiler and the CPU that
-		 * this can't be reordered: we have to complete the above
-		 * before going on. */
-		rmb();
-		/* Now we read the nanoseconds part. */
-		nsec = lguest_data.time.tv_nsec;
-		/* Make sure we've done that. */
-		rmb();
-		/* Now if the seconds part has changed, try again. */
-	} while (unlikely(lguest_data.time.tv_sec != sec));
-
-	/* Our non-TSC clock is in real nanoseconds. */
-	return sec*1000000000ULL + nsec;
-}
-
-/* This is what we tell the kernel is our clocksource.  */
-static struct clocksource lguest_clock = {
-	.name		= "lguest",
-	.rating		= 400,
-	.read		= lguest_clock_read,
-	.mask		= CLOCKSOURCE_MASK(64),
-	.mult		= 1 << 22,
-	.shift		= 22,
-};
-
-/* The "scheduler clock" is just our real clock, adjusted to start at zero */
-static unsigned long long lguest_sched_clock(void)
-{
-	return cyc2ns(&lguest_clock, lguest_clock_read() - clock_base);
-}
-
-/* We also need a "struct clock_event_device": Linux asks us to set it to go
- * off some time in the future.  Actually, James Morris figured all this out, I
- * just applied the patch. */
-static int lguest_clockevent_set_next_event(unsigned long delta,
-                                           struct clock_event_device *evt)
-{
-	if (delta < LG_CLOCK_MIN_DELTA) {
-		if (printk_ratelimit())
-			printk(KERN_DEBUG "%s: small delta %lu ns\n",
-			       __FUNCTION__, delta);
-		return -ETIME;
-	}
-	hcall(LHCALL_SET_CLOCKEVENT, delta, 0, 0);
-	return 0;
-}
-
-static void lguest_clockevent_set_mode(enum clock_event_mode mode,
-                                      struct clock_event_device *evt)
-{
-	switch (mode) {
-	case CLOCK_EVT_MODE_UNUSED:
-	case CLOCK_EVT_MODE_SHUTDOWN:
-		/* A 0 argument shuts the clock down. */
-		hcall(LHCALL_SET_CLOCKEVENT, 0, 0, 0);
-		break;
-	case CLOCK_EVT_MODE_ONESHOT:
-		/* This is what we expect. */
-		break;
-	case CLOCK_EVT_MODE_PERIODIC:
-		BUG();
-	case CLOCK_EVT_MODE_RESUME:
-		break;
-	}
-}
-
-/* This describes our primitive timer chip. */
-static struct clock_event_device lguest_clockevent = {
-	.name                   = "lguest",
-	.features               = CLOCK_EVT_FEAT_ONESHOT,
-	.set_next_event         = lguest_clockevent_set_next_event,
-	.set_mode               = lguest_clockevent_set_mode,
-	.rating                 = INT_MAX,
-	.mult                   = 1,
-	.shift                  = 0,
-	.min_delta_ns           = LG_CLOCK_MIN_DELTA,
-	.max_delta_ns           = LG_CLOCK_MAX_DELTA,
-};
-
-/* This is the Guest timer interrupt handler (hardware interrupt 0).  We just
- * call the clockevent infrastructure and it does whatever needs doing. */
-static void lguest_time_irq(unsigned int irq, struct irq_desc *desc)
-{
-	unsigned long flags;
-
-	/* Don't interrupt us while this is running. */
-	local_irq_save(flags);
-	lguest_clockevent.event_handler(&lguest_clockevent);
-	local_irq_restore(flags);
-}
-
-/* At some point in the boot process, we get asked to set up our timing
- * infrastructure.  The kernel doesn't expect timer interrupts before this, but
- * we cleverly initialized the "blocked_interrupts" field of "struct
- * lguest_data" so that timer interrupts were blocked until now. */
-static void lguest_time_init(void)
-{
-	/* Set up the timer interrupt (0) to go to our simple timer routine */
-	set_irq_handler(0, lguest_time_irq);
-
-	/* Our clock structure look like arch/i386/kernel/tsc.c if we can use
-	 * the TSC, otherwise it's a dumb nanosecond-resolution clock.  Either
-	 * way, the "rating" is initialized so high that it's always chosen
-	 * over any other clocksource. */
-	if (lguest_data.tsc_khz) {
-		lguest_clock.mult = clocksource_khz2mult(lguest_data.tsc_khz,
-							 lguest_clock.shift);
-		lguest_clock.flags = CLOCK_SOURCE_IS_CONTINUOUS;
-	}
-	clock_base = lguest_clock_read();
-	clocksource_register(&lguest_clock);
-
-	/* Now we've set up our clock, we can use it as the scheduler clock */
-	pv_time_ops.sched_clock = lguest_sched_clock;
-
-	/* We can't set cpumask in the initializer: damn C limitations!  Set it
-	 * here and register our timer device. */
-	lguest_clockevent.cpumask = cpumask_of_cpu(0);
-	clockevents_register_device(&lguest_clockevent);
-
-	/* Finally, we unblock the timer interrupt. */
-	enable_lguest_irq(0);
-}
-
-/*
- * Miscellaneous bits and pieces.
- *
- * Here is an oddball collection of functions which the Guest needs for things
- * to work.  They're pretty simple.
- */
-
-/* The Guest needs to tell the host what stack it expects traps to use.  For
- * native hardware, this is part of the Task State Segment mentioned above in
- * lguest_load_tr_desc(), but to help hypervisors there's this special call.
- *
- * We tell the Host the segment we want to use (__KERNEL_DS is the kernel data
- * segment), the privilege level (we're privilege level 1, the Host is 0 and
- * will not tolerate us trying to use that), the stack pointer, and the number
- * of pages in the stack. */
-static void lguest_load_esp0(struct tss_struct *tss,
-				     struct thread_struct *thread)
-{
-	lazy_hcall(LHCALL_SET_STACK, __KERNEL_DS|0x1, thread->esp0,
-		   THREAD_SIZE/PAGE_SIZE);
-}
-
-/* Let's just say, I wouldn't do debugging under a Guest. */
-static void lguest_set_debugreg(int regno, unsigned long value)
-{
-	/* FIXME: Implement */
-}
-
-/* There are times when the kernel wants to make sure that no memory writes are
- * caught in the cache (that they've all reached real hardware devices).  This
- * doesn't matter for the Guest which has virtual hardware.
- *
- * On the Pentium 4 and above, cpuid() indicates that the Cache Line Flush
- * (clflush) instruction is available and the kernel uses that.  Otherwise, it
- * uses the older "Write Back and Invalidate Cache" (wbinvd) instruction.
- * Unlike clflush, wbinvd can only be run at privilege level 0.  So we can
- * ignore clflush, but replace wbinvd.
- */
-static void lguest_wbinvd(void)
-{
-}
-
-/* If the Guest expects to have an Advanced Programmable Interrupt Controller,
- * we play dumb by ignoring writes and returning 0 for reads.  So it's no
- * longer Programmable nor Controlling anything, and I don't think 8 lines of
- * code qualifies for Advanced.  It will also never interrupt anything.  It
- * does, however, allow us to get through the Linux boot code. */
-#ifdef CONFIG_X86_LOCAL_APIC
-static void lguest_apic_write(unsigned long reg, unsigned long v)
-{
-}
-
-static unsigned long lguest_apic_read(unsigned long reg)
-{
-	return 0;
-}
-#endif
-
-/* STOP!  Until an interrupt comes in. */
-static void lguest_safe_halt(void)
-{
-	hcall(LHCALL_HALT, 0, 0, 0);
-}
-
-/* Perhaps CRASH isn't the best name for this hypercall, but we use it to get a
- * message out when we're crashing as well as elegant termination like powering
- * off.
- *
- * Note that the Host always prefers that the Guest speak in physical addresses
- * rather than virtual addresses, so we use __pa() here. */
-static void lguest_power_off(void)
-{
-	hcall(LHCALL_CRASH, __pa("Power down"), 0, 0);
-}
-
-/*
- * Panicing.
- *
- * Don't.  But if you did, this is what happens.
- */
-static int lguest_panic(struct notifier_block *nb, unsigned long l, void *p)
-{
-	hcall(LHCALL_CRASH, __pa(p), 0, 0);
-	/* The hcall won't return, but to keep gcc happy, we're "done". */
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block paniced = {
-	.notifier_call = lguest_panic
-};
-
-/* Setting up memory is fairly easy. */
-static __init char *lguest_memory_setup(void)
-{
-	/* We do this here and not earlier because lockcheck barfs if we do it
-	 * before start_kernel() */
-	atomic_notifier_chain_register(&panic_notifier_list, &paniced);
-
-	/* The Linux bootloader header contains an "e820" memory map: the
-	 * Launcher populated the first entry with our memory limit. */
-	add_memory_region(boot_params.e820_map[0].addr,
-			  boot_params.e820_map[0].size,
-			  boot_params.e820_map[0].type);
-
-	/* This string is for the boot messages. */
-	return "LGUEST";
-}
-
-/*G:050
- * Patching (Powerfully Placating Performance Pedants)
- *
- * We have already seen that pv_ops structures let us replace simple
- * native instructions with calls to the appropriate back end all throughout
- * the kernel.  This allows the same kernel to run as a Guest and as a native
- * kernel, but it's slow because of all the indirect branches.
- *
- * Remember that David Wheeler quote about "Any problem in computer science can
- * be solved with another layer of indirection"?  The rest of that quote is
- * "... But that usually will create another problem."  This is the first of
- * those problems.
- *
- * Our current solution is to allow the paravirt back end to optionally patch
- * over the indirect calls to replace them with something more efficient.  We
- * patch the four most commonly called functions: disable interrupts, enable
- * interrupts, restore interrupts and save interrupts.  We usually have 10
- * bytes to patch into: the Guest versions of these operations are small enough
- * that we can fit comfortably.
- *
- * First we need assembly templates of each of the patchable Guest operations,
- * and these are in lguest_asm.S. */
-
-/*G:060 We construct a table from the assembler templates: */
-static const struct lguest_insns
-{
-	const char *start, *end;
-} lguest_insns[] = {
-	[PARAVIRT_PATCH(pv_irq_ops.irq_disable)] = { lgstart_cli, lgend_cli },
-	[PARAVIRT_PATCH(pv_irq_ops.irq_enable)] = { lgstart_sti, lgend_sti },
-	[PARAVIRT_PATCH(pv_irq_ops.restore_fl)] = { lgstart_popf, lgend_popf },
-	[PARAVIRT_PATCH(pv_irq_ops.save_fl)] = { lgstart_pushf, lgend_pushf },
-};
-
-/* Now our patch routine is fairly simple (based on the native one in
- * paravirt.c).  If we have a replacement, we copy it in and return how much of
- * the available space we used. */
-static unsigned lguest_patch(u8 type, u16 clobber, void *ibuf,
-			     unsigned long addr, unsigned len)
-{
-	unsigned int insn_len;
-
-	/* Don't do anything special if we don't have a replacement */
-	if (type >= ARRAY_SIZE(lguest_insns) || !lguest_insns[type].start)
-		return paravirt_patch_default(type, clobber, ibuf, addr, len);
-
-	insn_len = lguest_insns[type].end - lguest_insns[type].start;
-
-	/* Similarly if we can't fit replacement (shouldn't happen, but let's
-	 * be thorough). */
-	if (len < insn_len)
-		return paravirt_patch_default(type, clobber, ibuf, addr, len);
-
-	/* Copy in our instructions. */
-	memcpy(ibuf, lguest_insns[type].start, insn_len);
-	return insn_len;
-}
-
-/*G:030 Once we get to lguest_init(), we know we're a Guest.  The pv_ops
- * structures in the kernel provide points for (almost) every routine we have
- * to override to avoid privileged instructions. */
-__init void lguest_init(void *boot)
-{
-	/* Copy boot parameters first: the Launcher put the physical location
-	 * in %esi, and head.S converted that to a virtual address and handed
-	 * it to us.  We use "__memcpy" because "memcpy" sometimes tries to do
-	 * tricky things to go faster, and we're not ready for that. */
-	__memcpy(&boot_params, boot, PARAM_SIZE);
-	/* The boot parameters also tell us where the command-line is: save
-	 * that, too. */
-	__memcpy(boot_command_line, __va(boot_params.hdr.cmd_line_ptr),
-	       COMMAND_LINE_SIZE);
-
-	/* We're under lguest, paravirt is enabled, and we're running at
-	 * privilege level 1, not 0 as normal. */
-	pv_info.name = "lguest";
-	pv_info.paravirt_enabled = 1;
-	pv_info.kernel_rpl = 1;
-
-	/* We set up all the lguest overrides for sensitive operations.  These
-	 * are detailed with the operations themselves. */
-
-	/* interrupt-related operations */
-	pv_irq_ops.init_IRQ = lguest_init_IRQ;
-	pv_irq_ops.save_fl = save_fl;
-	pv_irq_ops.restore_fl = restore_fl;
-	pv_irq_ops.irq_disable = irq_disable;
-	pv_irq_ops.irq_enable = irq_enable;
-	pv_irq_ops.safe_halt = lguest_safe_halt;
-
-	/* init-time operations */
-	pv_init_ops.memory_setup = lguest_memory_setup;
-	pv_init_ops.patch = lguest_patch;
-
-	/* Intercepts of various cpu instructions */
-	pv_cpu_ops.load_gdt = lguest_load_gdt;
-	pv_cpu_ops.cpuid = lguest_cpuid;
-	pv_cpu_ops.load_idt = lguest_load_idt;
-	pv_cpu_ops.iret = lguest_iret;
-	pv_cpu_ops.load_esp0 = lguest_load_esp0;
-	pv_cpu_ops.load_tr_desc = lguest_load_tr_desc;
-	pv_cpu_ops.set_ldt = lguest_set_ldt;
-	pv_cpu_ops.load_tls = lguest_load_tls;
-	pv_cpu_ops.set_debugreg = lguest_set_debugreg;
-	pv_cpu_ops.clts = lguest_clts;
-	pv_cpu_ops.read_cr0 = lguest_read_cr0;
-	pv_cpu_ops.write_cr0 = lguest_write_cr0;
-	pv_cpu_ops.read_cr4 = lguest_read_cr4;
-	pv_cpu_ops.write_cr4 = lguest_write_cr4;
-	pv_cpu_ops.write_gdt_entry = lguest_write_gdt_entry;
-	pv_cpu_ops.write_idt_entry = lguest_write_idt_entry;
-	pv_cpu_ops.wbinvd = lguest_wbinvd;
-	pv_cpu_ops.lazy_mode.enter = paravirt_enter_lazy_cpu;
-	pv_cpu_ops.lazy_mode.leave = lguest_leave_lazy_mode;
-
-	/* pagetable management */
-	pv_mmu_ops.write_cr3 = lguest_write_cr3;
-	pv_mmu_ops.flush_tlb_user = lguest_flush_tlb_user;
-	pv_mmu_ops.flush_tlb_single = lguest_flush_tlb_single;
-	pv_mmu_ops.flush_tlb_kernel = lguest_flush_tlb_kernel;
-	pv_mmu_ops.set_pte = lguest_set_pte;
-	pv_mmu_ops.set_pte_at = lguest_set_pte_at;
-	pv_mmu_ops.set_pmd = lguest_set_pmd;
-	pv_mmu_ops.read_cr2 = lguest_read_cr2;
-	pv_mmu_ops.read_cr3 = lguest_read_cr3;
-	pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu;
-	pv_mmu_ops.lazy_mode.leave = lguest_leave_lazy_mode;
-
-#ifdef CONFIG_X86_LOCAL_APIC
-	/* apic read/write intercepts */
-	pv_apic_ops.apic_write = lguest_apic_write;
-	pv_apic_ops.apic_write_atomic = lguest_apic_write;
-	pv_apic_ops.apic_read = lguest_apic_read;
-#endif
-
-	/* time operations */
-	pv_time_ops.get_wallclock = lguest_get_wallclock;
-	pv_time_ops.time_init = lguest_time_init;
-
-	/* Now is a good time to look at the implementations of these functions
-	 * before returning to the rest of lguest_init(). */
-
-	/*G:070 Now we've seen all the paravirt_ops, we return to
-	 * lguest_init() where the rest of the fairly chaotic boot setup
-	 * occurs.
-	 *
-	 * The Host expects our first hypercall to tell it where our "struct
-	 * lguest_data" is, so we do that first. */
-	hcall(LHCALL_LGUEST_INIT, __pa(&lguest_data), 0, 0);
-
-	/* The native boot code sets up initial page tables immediately after
-	 * the kernel itself, and sets init_pg_tables_end so they're not
-	 * clobbered.  The Launcher places our initial pagetables somewhere at
-	 * the top of our physical memory, so we don't need extra space: set
-	 * init_pg_tables_end to the end of the kernel. */
-	init_pg_tables_end = __pa(pg0);
-
-	/* Load the %fs segment register (the per-cpu segment register) with
-	 * the normal data segment to get through booting. */
-	asm volatile ("mov %0, %%fs" : : "r" (__KERNEL_DS) : "memory");
-
-	/* Clear the part of the kernel data which is expected to be zero.
-	 * Normally it will be anyway, but if we're loading from a bzImage with
-	 * CONFIG_RELOCATALE=y, the relocations will be sitting here. */
-	memset(__bss_start, 0, __bss_stop - __bss_start);
-
-	/* The Host uses the top of the Guest's virtual address space for the
-	 * Host<->Guest Switcher, and it tells us how much it needs in
-	 * lguest_data.reserve_mem, set up on the LGUEST_INIT hypercall. */
-	reserve_top_address(lguest_data.reserve_mem);
-
-	/* If we don't initialize the lock dependency checker now, it crashes
-	 * paravirt_disable_iospace. */
-	lockdep_init();
-
-	/* The IDE code spends about 3 seconds probing for disks: if we reserve
-	 * all the I/O ports up front it can't get them and so doesn't probe.
-	 * Other device drivers are similar (but less severe).  This cuts the
-	 * kernel boot time on my machine from 4.1 seconds to 0.45 seconds. */
-	paravirt_disable_iospace();
-
-	/* This is messy CPU setup stuff which the native boot code does before
-	 * start_kernel, so we have to do, too: */
-	cpu_detect(&new_cpu_data);
-	/* head.S usually sets up the first capability word, so do it here. */
-	new_cpu_data.x86_capability[0] = cpuid_edx(1);
-
-	/* Math is always hard! */
-	new_cpu_data.hard_math = 1;
-
-#ifdef CONFIG_X86_MCE
-	mce_disabled = 1;
-#endif
-#ifdef CONFIG_ACPI
-	acpi_disabled = 1;
-	acpi_ht = 0;
-#endif
-
-	/* We set the perferred console to "hvc".  This is the "hypervisor
-	 * virtual console" driver written by the PowerPC people, which we also
-	 * adapted for lguest's use. */
-	add_preferred_console("hvc", 0, NULL);
-
-	/* Last of all, we set the power management poweroff hook to point to
-	 * the Guest routine to power off. */
-	pm_power_off = lguest_power_off;
-
-	/* Now we're set up, call start_kernel() in init/main.c and we proceed
-	 * to boot as normal.  It never returns. */
-	start_kernel();
-}
-/*
- * This marks the end of stage II of our journey, The Guest.
- *
- * It is now time for us to explore the nooks and crannies of the three Guest
- * devices and complete our understanding of the Guest in "make Drivers".
- */
diff --git a/drivers/lguest/lguest_asm.S b/drivers/lguest/lguest_asm.S
deleted file mode 100644
index 1ddcd5c..0000000
--- a/drivers/lguest/lguest_asm.S
+++ /dev/null
@@ -1,93 +0,0 @@
-#include <linux/linkage.h>
-#include <linux/lguest.h>
-#include <asm/asm-offsets.h>
-#include <asm/thread_info.h>
-#include <asm/processor-flags.h>
-
-/*G:020 This is where we begin: we have a magic signature which the launcher
- * looks for.  The plan is that the Linux boot protocol will be extended with a
- * "platform type" field which will guide us here from the normal entry point,
- * but for the moment this suffices.  The normal boot code uses %esi for the
- * boot header, so we do too.  We convert it to a virtual address by adding
- * PAGE_OFFSET, and hand it to lguest_init() as its argument (ie. %eax).
- *
- * The .section line puts this code in .init.text so it will be discarded after
- * boot. */
-.section .init.text, "ax", @progbits
-.ascii "GenuineLguest"
-	/* Set up initial stack. */
- 	movl $(init_thread_union+THREAD_SIZE),%esp
-	movl %esi, %eax
-	addl $__PAGE_OFFSET, %eax
-	jmp lguest_init
-
-/*G:055 We create a macro which puts the assembler code between lgstart_ and
- * lgend_ markers.  These templates are put in the .text section: they can't be
- * discarded after boot as we may need to patch modules, too. */
-.text
-#define LGUEST_PATCH(name, insns...)			\
-	lgstart_##name:	insns; lgend_##name:;		\
-	.globl lgstart_##name; .globl lgend_##name
-
-LGUEST_PATCH(cli, movl $0, lguest_data+LGUEST_DATA_irq_enabled)
-LGUEST_PATCH(sti, movl $X86_EFLAGS_IF, lguest_data+LGUEST_DATA_irq_enabled)
-LGUEST_PATCH(popf, movl %eax, lguest_data+LGUEST_DATA_irq_enabled)
-LGUEST_PATCH(pushf, movl lguest_data+LGUEST_DATA_irq_enabled, %eax)
-/*:*/
-
-/* These demark the EIP range where host should never deliver interrupts. */
-.global lguest_noirq_start
-.global lguest_noirq_end
-
-/*M:004 When the Host reflects a trap or injects an interrupt into the Guest,
- * it sets the eflags interrupt bit on the stack based on
- * lguest_data.irq_enabled, so the Guest iret logic does the right thing when
- * restoring it.  However, when the Host sets the Guest up for direct traps,
- * such as system calls, the processor is the one to push eflags onto the
- * stack, and the interrupt bit will be 1 (in reality, interrupts are always
- * enabled in the Guest).
- *
- * This turns out to be harmless: the only trap which should happen under Linux
- * with interrupts disabled is Page Fault (due to our lazy mapping of vmalloc
- * regions), which has to be reflected through the Host anyway.  If another
- * trap *does* go off when interrupts are disabled, the Guest will panic, and
- * we'll never get to this iret! :*/
-
-/*G:045 There is one final paravirt_op that the Guest implements, and glancing
- * at it you can see why I left it to last.  It's *cool*!  It's in *assembler*!
- *
- * The "iret" instruction is used to return from an interrupt or trap.  The
- * stack looks like this:
- *   old address
- *   old code segment & privilege level
- *   old processor flags ("eflags")
- *
- * The "iret" instruction pops those values off the stack and restores them all
- * at once.  The only problem is that eflags includes the Interrupt Flag which
- * the Guest can't change: the CPU will simply ignore it when we do an "iret".
- * So we have to copy eflags from the stack to lguest_data.irq_enabled before
- * we do the "iret".
- *
- * There are two problems with this: firstly, we need to use a register to do
- * the copy and secondly, the whole thing needs to be atomic.  The first
- * problem is easy to solve: push %eax on the stack so we can use it, and then
- * restore it at the end just before the real "iret".
- *
- * The second is harder: copying eflags to lguest_data.irq_enabled will turn
- * interrupts on before we're finished, so we could be interrupted before we
- * return to userspace or wherever.  Our solution to this is to surround the
- * code with lguest_noirq_start: and lguest_noirq_end: labels.  We tell the
- * Host that it is *never* to interrupt us there, even if interrupts seem to be
- * enabled. */
-ENTRY(lguest_iret)
-	pushl	%eax
-	movl	12(%esp), %eax
-lguest_noirq_start:
-	/* Note the %ss: segment prefix here.  Normal data accesses use the
-	 * "ds" segment, but that will have already been restored for whatever
-	 * we're returning to (such as userspace): we can't trust it.  The %ss:
-	 * prefix makes sure we use the stack segment, which is still valid. */
-	movl	%eax,%ss:lguest_data+LGUEST_DATA_irq_enabled
-	popl	%eax
-	iret
-lguest_noirq_end:
diff --git a/drivers/lguest/lguest_bus.c b/drivers/lguest/lguest_bus.c
deleted file mode 100644
index 57329788..0000000
--- a/drivers/lguest/lguest_bus.c
+++ /dev/null
@@ -1,218 +0,0 @@
-/*P:050 Lguest guests use a very simple bus for devices.  It's a simple array
- * of device descriptors contained just above the top of normal memory.  The
- * lguest bus is 80% tedious boilerplate code. :*/
-#include <linux/init.h>
-#include <linux/bootmem.h>
-#include <linux/lguest_bus.h>
-#include <asm/io.h>
-#include <asm/paravirt.h>
-
-static ssize_t type_show(struct device *_dev,
-                         struct device_attribute *attr, char *buf)
-{
-	struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
-	return sprintf(buf, "%hu", lguest_devices[dev->index].type);
-}
-static ssize_t features_show(struct device *_dev,
-                             struct device_attribute *attr, char *buf)
-{
-	struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
-	return sprintf(buf, "%hx", lguest_devices[dev->index].features);
-}
-static ssize_t pfn_show(struct device *_dev,
-			 struct device_attribute *attr, char *buf)
-{
-	struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
-	return sprintf(buf, "%u", lguest_devices[dev->index].pfn);
-}
-static ssize_t status_show(struct device *_dev,
-                           struct device_attribute *attr, char *buf)
-{
-	struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
-	return sprintf(buf, "%hx", lguest_devices[dev->index].status);
-}
-static ssize_t status_store(struct device *_dev, struct device_attribute *attr,
-                            const char *buf, size_t count)
-{
-	struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
-	if (sscanf(buf, "%hi", &lguest_devices[dev->index].status) != 1)
-		return -EINVAL;
-	return count;
-}
-static struct device_attribute lguest_dev_attrs[] = {
-	__ATTR_RO(type),
-	__ATTR_RO(features),
-	__ATTR_RO(pfn),
-	__ATTR(status, 0644, status_show, status_store),
-	__ATTR_NULL
-};
-
-/*D:130 The generic bus infrastructure requires a function which says whether a
- * device matches a driver.  For us, it is simple: "struct lguest_driver"
- * contains a "device_type" field which indicates what type of device it can
- * handle, so we just cast the args and compare: */
-static int lguest_dev_match(struct device *_dev, struct device_driver *_drv)
-{
-	struct lguest_device *dev = container_of(_dev,struct lguest_device,dev);
-	struct lguest_driver *drv = container_of(_drv,struct lguest_driver,drv);
-
-	return (drv->device_type == lguest_devices[dev->index].type);
-}
-/*:*/
-
-struct lguest_bus {
-	struct bus_type bus;
-	struct device dev;
-};
-
-static struct lguest_bus lguest_bus = {
-	.bus = {
-		.name  = "lguest",
-		.match = lguest_dev_match,
-		.dev_attrs = lguest_dev_attrs,
-	},
-	.dev = {
-		.parent = NULL,
-		.bus_id = "lguest",
-	}
-};
-
-/*D:140 This is the callback which occurs once the bus infrastructure matches
- * up a device and driver, ie. in response to add_lguest_device() calling
- * device_register(), or register_lguest_driver() calling driver_register().
- *
- * At the moment it's always the latter: the devices are added first, since
- * scan_devices() is called from a "core_initcall", and the drivers themselves
- * called later as a normal "initcall".  But it would work the other way too.
- *
- * So now we have the happy couple, we add the status bit to indicate that we
- * found a driver.  If the driver truly loves the device, it will return
- * happiness from its probe function (ok, perhaps this wasn't my greatest
- * analogy), and we set the final "driver ok" bit so the Host sees it's all
- * green. */
-static int lguest_dev_probe(struct device *_dev)
-{
-	int ret;
-	struct lguest_device*dev = container_of(_dev,struct lguest_device,dev);
-	struct lguest_driver*drv = container_of(dev->dev.driver,
-						struct lguest_driver, drv);
-
-	lguest_devices[dev->index].status |= LGUEST_DEVICE_S_DRIVER;
-	ret = drv->probe(dev);
-	if (ret == 0)
-		lguest_devices[dev->index].status |= LGUEST_DEVICE_S_DRIVER_OK;
-	return ret;
-}
-
-/* The last part of the bus infrastructure is the function lguest drivers use
- * to register themselves.  Firstly, we do nothing if there's no lguest bus
- * (ie. this is not a Guest), otherwise we fill in the embedded generic "struct
- * driver" fields and call the generic driver_register(). */
-int register_lguest_driver(struct lguest_driver *drv)
-{
-	if (!lguest_devices)
-		return 0;
-
-	drv->drv.bus = &lguest_bus.bus;
-	drv->drv.name = drv->name;
-	drv->drv.owner = drv->owner;
-	drv->drv.probe = lguest_dev_probe;
-
-	return driver_register(&drv->drv);
-}
-
-/* At the moment we build all the drivers into the kernel because they're so
- * simple: 8144 bytes for all three of them as I type this.  And as the console
- * really needs to be built in, it's actually only 3527 bytes for the network
- * and block drivers.
- *
- * If they get complex it will make sense for them to be modularized, so we
- * need to explicitly export the symbol.
- *
- * I don't think non-GPL modules make sense, so it's a GPL-only export.
- */
-EXPORT_SYMBOL_GPL(register_lguest_driver);
-
-/*D:120 This is the core of the lguest bus: actually adding a new device.
- * It's a separate function because it's neater that way, and because an
- * earlier version of the code supported hotplug and unplug.  They were removed
- * early on because they were never used.
- *
- * As Andrew Tridgell says, "Untested code is buggy code".
- *
- * It's worth reading this carefully: we start with an index into the array of
- * "struct lguest_device_desc"s indicating the device which is new: */
-static void add_lguest_device(unsigned int index)
-{
-	struct lguest_device *new;
-
-	/* Each "struct lguest_device_desc" has a "status" field, which the
-	 * Guest updates as the device is probed.  In the worst case, the Host
-	 * can look at these bits to tell what part of device setup failed,
-	 * even if the console isn't available. */
-	lguest_devices[index].status |= LGUEST_DEVICE_S_ACKNOWLEDGE;
-	new = kmalloc(sizeof(struct lguest_device), GFP_KERNEL);
-	if (!new) {
-		printk(KERN_EMERG "Cannot allocate lguest device %u\n", index);
-		lguest_devices[index].status |= LGUEST_DEVICE_S_FAILED;
-		return;
-	}
-
-	/* The "struct lguest_device" setup is pretty straight-forward example
-	 * code. */
-	new->index = index;
-	new->private = NULL;
-	memset(&new->dev, 0, sizeof(new->dev));
-	new->dev.parent = &lguest_bus.dev;
-	new->dev.bus = &lguest_bus.bus;
-	sprintf(new->dev.bus_id, "%u", index);
-
-	/* device_register() causes the bus infrastructure to look for a
-	 * matching driver. */
-	if (device_register(&new->dev) != 0) {
-		printk(KERN_EMERG "Cannot register lguest device %u\n", index);
-		lguest_devices[index].status |= LGUEST_DEVICE_S_FAILED;
-		kfree(new);
-	}
-}
-
-/*D:110 scan_devices() simply iterates through the device array.  The type 0
- * is reserved to mean "no device", and anything else means we have found a
- * device: add it. */
-static void scan_devices(void)
-{
-	unsigned int i;
-
-	for (i = 0; i < LGUEST_MAX_DEVICES; i++)
-		if (lguest_devices[i].type)
-			add_lguest_device(i);
-}
-
-/*D:100 Fairly early in boot, lguest_bus_init() is called to set up the lguest
- * bus.  We check that we are a Guest by checking paravirt_ops.name: there are
- * other ways of checking, but this seems most obvious to me.
- *
- * So we can access the array of "struct lguest_device_desc"s easily, we map
- * that memory and store the pointer in the global "lguest_devices".  Then we
- * register the bus with the core.  Doing two registrations seems clunky to me,
- * but it seems to be the correct sysfs incantation.
- *
- * Finally we call scan_devices() which adds all the devices found in the
- * "struct lguest_device_desc" array. */
-static int __init lguest_bus_init(void)
-{
-	if (strcmp(pv_info.name, "lguest") != 0)
-		return 0;
-
-	/* Devices are in a single page above top of "normal" mem */
-	lguest_devices = lguest_map(max_pfn<<PAGE_SHIFT, 1);
-
-	if (bus_register(&lguest_bus.bus) != 0
-	    || device_register(&lguest_bus.dev) != 0)
-		panic("lguest bus registration failed");
-
-	scan_devices();
-	return 0;
-}
-/* Do this after core stuff, before devices. */
-postcore_initcall(lguest_bus_init);
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
new file mode 100644
index 0000000..71c6483
--- /dev/null
+++ b/drivers/lguest/lguest_device.c
@@ -0,0 +1,373 @@
+/*P:050 Lguest guests use a very simple method to describe devices.  It's a
+ * series of device descriptors contained just above the top of normal
+ * memory.
+ *
+ * We use the standard "virtio" device infrastructure, which provides us with a
+ * console, a network and a block driver.  Each one expects some configuration
+ * information and a "virtqueue" mechanism to send and receive data. :*/
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/lguest_launcher.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/interrupt.h>
+#include <linux/virtio_ring.h>
+#include <linux/err.h>
+#include <asm/io.h>
+#include <asm/paravirt.h>
+#include <asm/lguest_hcall.h>
+
+/* The pointer to our (page) of device descriptions. */
+static void *lguest_devices;
+
+/* Unique numbering for lguest devices. */
+static unsigned int dev_index;
+
+/* For Guests, device memory can be used as normal memory, so we cast away the
+ * __iomem to quieten sparse. */
+static inline void *lguest_map(unsigned long phys_addr, unsigned long pages)
+{
+	return (__force void *)ioremap(phys_addr, PAGE_SIZE*pages);
+}
+
+static inline void lguest_unmap(void *addr)
+{
+	iounmap((__force void __iomem *)addr);
+}
+
+/*D:100 Each lguest device is just a virtio device plus a pointer to its entry
+ * in the lguest_devices page. */
+struct lguest_device {
+	struct virtio_device vdev;
+
+	/* The entry in the lguest_devices page for this device. */
+	struct lguest_device_desc *desc;
+};
+
+/* Since the virtio infrastructure hands us a pointer to the virtio_device all
+ * the time, it helps to have a curt macro to get a pointer to the struct
+ * lguest_device it's enclosed in.  */
+#define to_lgdev(vdev) container_of(vdev, struct lguest_device, vdev)
+
+/*D:130
+ * Device configurations
+ *
+ * The configuration information for a device consists of a series of fields.
+ * The device will look for these fields during setup.
+ *
+ * For us these fields come immediately after that device's descriptor in the
+ * lguest_devices page.
+ *
+ * Each field starts with a "type" byte, a "length" byte, then that number of
+ * bytes of configuration information.  The device descriptor tells us the
+ * total configuration length so we know when we've reached the last field. */
+
+/* type + length bytes */
+#define FHDR_LEN 2
+
+/* This finds the first field of a given type for a device's configuration. */
+static void *lg_find(struct virtio_device *vdev, u8 type, unsigned int *len)
+{
+	struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
+	int i;
+
+	for (i = 0; i < desc->config_len; i += FHDR_LEN + desc->config[i+1]) {
+		if (desc->config[i] == type) {
+			/* Mark it used, so Host can know we looked at it, and
+			 * also so we won't find the same one twice. */
+			desc->config[i] |= 0x80;
+			/* Remember, the second byte is the length. */
+			*len = desc->config[i+1];
+			/* We return a pointer to the field header. */
+			return desc->config + i;
+		}
+	}
+
+	/* Not found: return NULL for failure. */
+	return NULL;
+}
+
+/* Once they've found a field, getting a copy of it is easy. */
+static void lg_get(struct virtio_device *vdev, void *token,
+		   void *buf, unsigned len)
+{
+	/* Check they didn't ask for more than the length of the field! */
+	BUG_ON(len > ((u8 *)token)[1]);
+	memcpy(buf, token + FHDR_LEN, len);
+}
+
+/* Setting the contents is also trivial. */
+static void lg_set(struct virtio_device *vdev, void *token,
+		   const void *buf, unsigned len)
+{
+	BUG_ON(len > ((u8 *)token)[1]);
+	memcpy(token + FHDR_LEN, buf, len);
+}
+
+/* The operations to get and set the status word just access the status field
+ * of the device descriptor. */
+static u8 lg_get_status(struct virtio_device *vdev)
+{
+	return to_lgdev(vdev)->desc->status;
+}
+
+static void lg_set_status(struct virtio_device *vdev, u8 status)
+{
+	to_lgdev(vdev)->desc->status = status;
+}
+
+/*
+ * Virtqueues
+ *
+ * The other piece of infrastructure virtio needs is a "virtqueue": a way of
+ * the Guest device registering buffers for the other side to read from or
+ * write into (ie. send and receive buffers).  Each device can have multiple
+ * virtqueues: for example the console has one queue for sending and one for
+ * receiving.
+ *
+ * Fortunately for us, a very fast shared-memory-plus-descriptors virtqueue
+ * already exists in virtio_ring.c.  We just need to connect it up.
+ *
+ * We start with the information we need to keep about each virtqueue.
+ */
+
+/*D:140 This is the information we remember about each virtqueue. */
+struct lguest_vq_info
+{
+	/* A copy of the information contained in the device config. */
+	struct lguest_vqconfig config;
+
+	/* The address where we mapped the virtio ring, so we can unmap it. */
+	void *pages;
+};
+
+/* When the virtio_ring code wants to prod the Host, it calls us here and we
+ * make a hypercall.  We hand the page number of the virtqueue so the Host
+ * knows which virtqueue we're talking about. */
+static void lg_notify(struct virtqueue *vq)
+{
+	/* We store our virtqueue information in the "priv" pointer of the
+	 * virtqueue structure. */
+	struct lguest_vq_info *lvq = vq->priv;
+
+	hcall(LHCALL_NOTIFY, lvq->config.pfn << PAGE_SHIFT, 0, 0);
+}
+
+/* This routine finds the first virtqueue described in the configuration of
+ * this device and sets it up.
+ *
+ * This is kind of an ugly duckling.  It'd be nicer to have a standard
+ * representation of a virtqueue in the configuration space, but it seems that
+ * everyone wants to do it differently.  The KVM guys want the Guest to
+ * allocate its own pages and tell the Host where they are, but for lguest it's
+ * simpler for the Host to simply tell us where the pages are.
+ *
+ * So we provide devices with a "find virtqueue and set it up" function. */
+static struct virtqueue *lg_find_vq(struct virtio_device *vdev,
+				    bool (*callback)(struct virtqueue *vq))
+{
+	struct lguest_vq_info *lvq;
+	struct virtqueue *vq;
+	unsigned int len;
+	void *token;
+	int err;
+
+	/* Look for a field of the correct type to mark a virtqueue.  Note that
+	 * if this succeeds, then the type will be changed so it won't be found
+	 * again, and future lg_find_vq() calls will find the next
+	 * virtqueue (if any). */
+	token = vdev->config->find(vdev, VIRTIO_CONFIG_F_VIRTQUEUE, &len);
+	if (!token)
+		return ERR_PTR(-ENOENT);
+
+	lvq = kmalloc(sizeof(*lvq), GFP_KERNEL);
+	if (!lvq)
+		return ERR_PTR(-ENOMEM);
+
+	/* Note: we could use a configuration space inside here, just like we
+	 * do for the device.  This would allow expansion in future, because
+	 * our configuration system is designed to be expansible.  But this is
+	 * way easier. */
+	if (len != sizeof(lvq->config)) {
+		dev_err(&vdev->dev, "Unexpected virtio config len %u\n", len);
+		err = -EIO;
+		goto free_lvq;
+	}
+	/* Make a copy of the "struct lguest_vqconfig" field.  We need a copy
+	 * because the config space might not be aligned correctly. */
+	vdev->config->get(vdev, token, &lvq->config, sizeof(lvq->config));
+
+	/* Figure out how many pages the ring will take, and map that memory */
+	lvq->pages = lguest_map((unsigned long)lvq->config.pfn << PAGE_SHIFT,
+				DIV_ROUND_UP(vring_size(lvq->config.num),
+					     PAGE_SIZE));
+	if (!lvq->pages) {
+		err = -ENOMEM;
+		goto free_lvq;
+	}
+
+	/* OK, tell virtio_ring.c to set up a virtqueue now we know its size
+	 * and we've got a pointer to its pages. */
+	vq = vring_new_virtqueue(lvq->config.num, vdev, lvq->pages,
+				 lg_notify, callback);
+	if (!vq) {
+		err = -ENOMEM;
+		goto unmap;
+	}
+
+	/* Tell the interrupt for this virtqueue to go to the virtio_ring
+	 * interrupt handler. */
+	/* FIXME: We used to have a flag for the Host to tell us we could use
+	 * the interrupt as a source of randomness: it'd be nice to have that
+	 * back.. */
+	err = request_irq(lvq->config.irq, vring_interrupt, IRQF_SHARED,
+			  vdev->dev.bus_id, vq);
+	if (err)
+		goto destroy_vring;
+
+	/* Last of all we hook up our 'struct lguest_vq_info" to the
+	 * virtqueue's priv pointer. */
+	vq->priv = lvq;
+	return vq;
+
+destroy_vring:
+	vring_del_virtqueue(vq);
+unmap:
+	lguest_unmap(lvq->pages);
+free_lvq:
+	kfree(lvq);
+	return ERR_PTR(err);
+}
+/*:*/
+
+/* Cleaning up a virtqueue is easy */
+static void lg_del_vq(struct virtqueue *vq)
+{
+	struct lguest_vq_info *lvq = vq->priv;
+
+	/* Tell virtio_ring.c to free the virtqueue. */
+	vring_del_virtqueue(vq);
+	/* Unmap the pages containing the ring. */
+	lguest_unmap(lvq->pages);
+	/* Free our own queue information. */
+	kfree(lvq);
+}
+
+/* The ops structure which hooks everything together. */
+static struct virtio_config_ops lguest_config_ops = {
+	.find = lg_find,
+	.get = lg_get,
+	.set = lg_set,
+	.get_status = lg_get_status,
+	.set_status = lg_set_status,
+	.find_vq = lg_find_vq,
+	.del_vq = lg_del_vq,
+};
+
+/* The root device for the lguest virtio devices.  This makes them appear as
+ * /sys/devices/lguest/0,1,2 not /sys/devices/0,1,2. */
+static struct device lguest_root = {
+	.parent = NULL,
+	.bus_id = "lguest",
+};
+
+/*D:120 This is the core of the lguest bus: actually adding a new device.
+ * It's a separate function because it's neater that way, and because an
+ * earlier version of the code supported hotplug and unplug.  They were removed
+ * early on because they were never used.
+ *
+ * As Andrew Tridgell says, "Untested code is buggy code".
+ *
+ * It's worth reading this carefully: we start with a pointer to the new device
+ * descriptor in the "lguest_devices" page. */
+static void add_lguest_device(struct lguest_device_desc *d)
+{
+	struct lguest_device *ldev;
+
+	ldev = kzalloc(sizeof(*ldev), GFP_KERNEL);
+	if (!ldev) {
+		printk(KERN_EMERG "Cannot allocate lguest dev %u\n",
+		       dev_index++);
+		return;
+	}
+
+	/* This devices' parent is the lguest/ dir. */
+	ldev->vdev.dev.parent = &lguest_root;
+	/* We have a unique device index thanks to the dev_index counter. */
+	ldev->vdev.index = dev_index++;
+	/* The device type comes straight from the descriptor.  There's also a
+	 * device vendor field in the virtio_device struct, which we leave as
+	 * 0. */
+	ldev->vdev.id.device = d->type;
+	/* We have a simple set of routines for querying the device's
+	 * configuration information and setting its status. */
+	ldev->vdev.config = &lguest_config_ops;
+	/* And we remember the device's descriptor for lguest_config_ops. */
+	ldev->desc = d;
+
+	/* register_virtio_device() sets up the generic fields for the struct
+	 * virtio_device and calls device_register().  This makes the bus
+	 * infrastructure look for a matching driver. */
+	if (register_virtio_device(&ldev->vdev) != 0) {
+		printk(KERN_ERR "Failed to register lguest device %u\n",
+		       ldev->vdev.index);
+		kfree(ldev);
+	}
+}
+
+/*D:110 scan_devices() simply iterates through the device page.  The type 0 is
+ * reserved to mean "end of devices". */
+static void scan_devices(void)
+{
+	unsigned int i;
+	struct lguest_device_desc *d;
+
+	/* We start at the page beginning, and skip over each entry. */
+	for (i = 0; i < PAGE_SIZE; i += sizeof(*d) + d->config_len) {
+		d = lguest_devices + i;
+
+		/* Once we hit a zero, stop. */
+		if (d->type == 0)
+			break;
+
+		add_lguest_device(d);
+	}
+}
+
+/*D:105 Fairly early in boot, lguest_devices_init() is called to set up the
+ * lguest device infrastructure.  We check that we are a Guest by checking
+ * pv_info.name: there are other ways of checking, but this seems most
+ * obvious to me.
+ *
+ * So we can access the "struct lguest_device_desc"s easily, we map that memory
+ * and store the pointer in the global "lguest_devices".  Then we register a
+ * root device from which all our devices will hang (this seems to be the
+ * correct sysfs incantation).
+ *
+ * Finally we call scan_devices() which adds all the devices found in the
+ * lguest_devices page. */
+static int __init lguest_devices_init(void)
+{
+	if (strcmp(pv_info.name, "lguest") != 0)
+		return 0;
+
+	if (device_register(&lguest_root) != 0)
+		panic("Could not register lguest root");
+
+	/* Devices are in a single page above top of "normal" mem */
+	lguest_devices = lguest_map(max_pfn<<PAGE_SHIFT, 1);
+
+	scan_devices();
+	return 0;
+}
+/* We do this after core stuff, but before the drivers. */
+postcore_initcall(lguest_devices_init);
+
+/*D:150 At this point in the journey we used to now wade through the lguest
+ * devices themselves: net, block and console.  Since they're all now virtio
+ * devices rather than lguest-specific, I've decided to ignore them.  Mostly,
+ * they're kind of boring.  But this does mean you'll never experience the
+ * thrill of reading the forbidden love scene buried deep in the block driver.
+ *
+ * "make Launcher" beckons, where we answer questions like "Where do Guests
+ * come from?", and "What do you do when someone asks for optimization?". */
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c
index 80d1b58..ee405b38 100644
--- a/drivers/lguest/lguest_user.c
+++ b/drivers/lguest/lguest_user.c
@@ -1,73 +1,17 @@
 /*P:200 This contains all the /dev/lguest code, whereby the userspace launcher
  * controls and communicates with the Guest.  For example, the first write will
- * tell us the memory size, pagetable, entry point and kernel address offset.
- * A read will run the Guest until a signal is pending (-EINTR), or the Guest
- * does a DMA out to the Launcher.  Writes are also used to get a DMA buffer
- * registered by the Guest and to send the Guest an interrupt. :*/
+ * tell us the Guest's memory layout, pagetable, entry point and kernel address
+ * offset.  A read will run the Guest until something happens, such as a signal
+ * or the Guest doing a NOTIFY out to the Launcher. :*/
 #include <linux/uaccess.h>
 #include <linux/miscdevice.h>
 #include <linux/fs.h>
 #include "lg.h"
 
-/*L:030 setup_regs() doesn't really belong in this file, but it gives us an
- * early glimpse deeper into the Host so it's worth having here.
- *
- * Most of the Guest's registers are left alone: we used get_zeroed_page() to
- * allocate the structure, so they will be 0. */
-static void setup_regs(struct lguest_regs *regs, unsigned long start)
-{
-	/* There are four "segment" registers which the Guest needs to boot:
-	 * The "code segment" register (cs) refers to the kernel code segment
-	 * __KERNEL_CS, and the "data", "extra" and "stack" segment registers
-	 * refer to the kernel data segment __KERNEL_DS.
-	 *
-	 * The privilege level is packed into the lower bits.  The Guest runs
-	 * at privilege level 1 (GUEST_PL).*/
-	regs->ds = regs->es = regs->ss = __KERNEL_DS|GUEST_PL;
-	regs->cs = __KERNEL_CS|GUEST_PL;
-
-	/* The "eflags" register contains miscellaneous flags.  Bit 1 (0x002)
-	 * is supposed to always be "1".  Bit 9 (0x200) controls whether
-	 * interrupts are enabled.  We always leave interrupts enabled while
-	 * running the Guest. */
-	regs->eflags = 0x202;
-
-	/* The "Extended Instruction Pointer" register says where the Guest is
-	 * running. */
-	regs->eip = start;
-
-	/* %esi points to our boot information, at physical address 0, so don't
-	 * touch it. */
-}
-
-/*L:310 To send DMA into the Guest, the Launcher needs to be able to ask for a
- * DMA buffer.  This is done by writing LHREQ_GETDMA and the key to
- * /dev/lguest. */
-static long user_get_dma(struct lguest *lg, const u32 __user *input)
-{
-	unsigned long key, udma, irq;
-
-	/* Fetch the key they wrote to us. */
-	if (get_user(key, input) != 0)
-		return -EFAULT;
-	/* Look for a free Guest DMA buffer bound to that key. */
-	udma = get_dma_buffer(lg, key, &irq);
-	if (!udma)
-		return -ENOENT;
-
-	/* We need to tell the Launcher what interrupt the Guest expects after
-	 * the buffer is filled.  We stash it in udma->used_len. */
-	lgwrite_u32(lg, udma + offsetof(struct lguest_dma, used_len), irq);
-
-	/* The (guest-physical) address of the DMA buffer is returned from
-	 * the write(). */
-	return udma;
-}
-
 /*L:315 To force the Guest to stop running and return to the Launcher, the
  * Waker sets writes LHREQ_BREAK and the value "1" to /dev/lguest.  The
  * Launcher then writes LHREQ_BREAK and "0" to release the Waker. */
-static int break_guest_out(struct lguest *lg, const u32 __user *input)
+static int break_guest_out(struct lguest *lg, const unsigned long __user *input)
 {
 	unsigned long on;
 
@@ -90,9 +34,9 @@ static int break_guest_out(struct lguest *lg, const u32 __user *input)
 
 /*L:050 Sending an interrupt is done by writing LHREQ_IRQ and an interrupt
  * number to /dev/lguest. */
-static int user_send_irq(struct lguest *lg, const u32 __user *input)
+static int user_send_irq(struct lguest *lg, const unsigned long __user *input)
 {
-	u32 irq;
+	unsigned long irq;
 
 	if (get_user(irq, input) != 0)
 		return -EFAULT;
@@ -133,17 +77,19 @@ static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o)
 		return len;
 	}
 
-	/* If we returned from read() last time because the Guest sent DMA,
+	/* If we returned from read() last time because the Guest notified,
 	 * clear the flag. */
-	if (lg->dma_is_pending)
-		lg->dma_is_pending = 0;
+	if (lg->pending_notify)
+		lg->pending_notify = 0;
 
 	/* Run the Guest until something interesting happens. */
 	return run_guest(lg, (unsigned long __user *)user);
 }
 
-/*L:020 The initialization write supplies 4 32-bit values (in addition to the
- * 32-bit LHREQ_INITIALIZE value).  These are:
+/*L:020 The initialization write supplies 4 pointer sized (32 or 64 bit)
+ * values (in addition to the LHREQ_INITIALIZE value).  These are:
+ *
+ * base: The start of the Guest-physical memory inside the Launcher memory.
  *
  * pfnlimit: The highest (Guest-physical) page number the Guest should be
  * allowed to access.  The Launcher has to live in Guest memory, so it sets
@@ -153,23 +99,17 @@ static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o)
  * pagetables (which are set up by the Launcher).
  *
  * start: The first instruction to execute ("eip" in x86-speak).
- *
- * page_offset: The PAGE_OFFSET constant in the Guest kernel.  We should
- * probably wean the code off this, but it's a very useful constant!  Any
- * address above this is within the Guest kernel, and any kernel address can
- * quickly converted from physical to virtual by adding PAGE_OFFSET.  It's
- * 0xC0000000 (3G) by default, but it's configurable at kernel build time.
  */
-static int initialize(struct file *file, const u32 __user *input)
+static int initialize(struct file *file, const unsigned long __user *input)
 {
 	/* "struct lguest" contains everything we (the Host) know about a
 	 * Guest. */
 	struct lguest *lg;
-	int err, i;
-	u32 args[4];
+	int err;
+	unsigned long args[4];
 
-	/* We grab the Big Lguest lock, which protects the global array
-	 * "lguests" and multiple simultaneous initializations. */
+	/* We grab the Big Lguest lock, which protects against multiple
+	 * simultaneous initializations. */
 	mutex_lock(&lguest_lock);
 	/* You can't initialize twice!  Close the device and start again... */
 	if (file->private_data) {
@@ -182,20 +122,15 @@ static int initialize(struct file *file, const u32 __user *input)
 		goto unlock;
 	}
 
-	/* Find an unused guest. */
-	i = find_free_guest();
-	if (i < 0) {
-		err = -ENOSPC;
+	lg = kzalloc(sizeof(*lg), GFP_KERNEL);
+	if (!lg) {
+		err = -ENOMEM;
 		goto unlock;
 	}
-	/* OK, we have an index into the "lguest" array: "lg" is a convenient
-	 * pointer. */
-	lg = &lguests[i];
 
 	/* Populate the easy fields of our "struct lguest" */
-	lg->guestid = i;
-	lg->pfn_limit = args[0];
-	lg->page_offset = args[3];
+	lg->mem_base = (void __user *)(long)args[0];
+	lg->pfn_limit = args[1];
 
 	/* We need a complete page for the Guest registers: they are accessible
 	 * to the Guest and we can only grant it access to whole pages. */
@@ -210,17 +145,13 @@ static int initialize(struct file *file, const u32 __user *input)
 	/* Initialize the Guest's shadow page tables, using the toplevel
 	 * address the Launcher gave us.  This allocates memory, so can
 	 * fail. */
-	err = init_guest_pagetable(lg, args[1]);
+	err = init_guest_pagetable(lg, args[2]);
 	if (err)
 		goto free_regs;
 
 	/* Now we initialize the Guest's registers, handing it the start
 	 * address. */
-	setup_regs(lg->regs, args[2]);
-
-	/* There are a couple of GDT entries the Guest expects when first
-	 * booting. */
-	setup_guest_gdt(lg);
+	lguest_arch_setup_regs(lg, args[3]);
 
 	/* The timer for lguest's clock needs initialization. */
 	init_clockdev(lg);
@@ -260,18 +191,19 @@ unlock:
 /*L:010 The first operation the Launcher does must be a write.  All writes
  * start with a 32 bit number: for the first write this must be
  * LHREQ_INITIALIZE to set up the Guest.  After that the Launcher can use
- * writes of other values to get DMA buffers and send interrupts. */
-static ssize_t write(struct file *file, const char __user *input,
+ * writes of other values to send interrupts. */
+static ssize_t write(struct file *file, const char __user *in,
 		     size_t size, loff_t *off)
 {
 	/* Once the guest is initialized, we hold the "struct lguest" in the
 	 * file private data. */
 	struct lguest *lg = file->private_data;
-	u32 req;
+	const unsigned long __user *input = (const unsigned long __user *)in;
+	unsigned long req;
 
 	if (get_user(req, input) != 0)
 		return -EFAULT;
-	input += sizeof(req);
+	input++;
 
 	/* If you haven't initialized, you must do that first. */
 	if (req != LHREQ_INITIALIZE && !lg)
@@ -287,13 +219,11 @@ static ssize_t write(struct file *file, const char __user *input,
 
 	switch (req) {
 	case LHREQ_INITIALIZE:
-		return initialize(file, (const u32 __user *)input);
-	case LHREQ_GETDMA:
-		return user_get_dma(lg, (const u32 __user *)input);
+		return initialize(file, input);
 	case LHREQ_IRQ:
-		return user_send_irq(lg, (const u32 __user *)input);
+		return user_send_irq(lg, input);
 	case LHREQ_BREAK:
-		return break_guest_out(lg, (const u32 __user *)input);
+		return break_guest_out(lg, input);
 	default:
 		return -EINVAL;
 	}
@@ -319,8 +249,6 @@ static int close(struct inode *inode, struct file *file)
 	mutex_lock(&lguest_lock);
 	/* Cancels the hrtimer set via LHCALL_SET_CLOCKEVENT. */
 	hrtimer_cancel(&lg->hrt);
-	/* Free any DMA buffers the Guest had bound. */
-	release_all_dma(lg);
 	/* Free up the shadow page tables for the Guest. */
 	free_guest_pagetable(lg);
 	/* Now all the memory cleanups are done, it's safe to release the
diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c
index b7a924a..2a45f06 100644
--- a/drivers/lguest/page_tables.c
+++ b/drivers/lguest/page_tables.c
@@ -13,6 +13,7 @@
 #include <linux/random.h>
 #include <linux/percpu.h>
 #include <asm/tlbflush.h>
+#include <asm/uaccess.h>
 #include "lg.h"
 
 /*M:008 We hold reference to pages, which prevents them from being swapped.
@@ -44,44 +45,32 @@
  *  (vii) Setting up the page tables initially.
  :*/
 
-/* Pages a 4k long, and each page table entry is 4 bytes long, giving us 1024
- * (or 2^10) entries per page. */
-#define PTES_PER_PAGE_SHIFT 10
-#define PTES_PER_PAGE (1 << PTES_PER_PAGE_SHIFT)
 
 /* 1024 entries in a page table page maps 1024 pages: 4MB.  The Switcher is
  * conveniently placed at the top 4MB, so it uses a separate, complete PTE
  * page.  */
-#define SWITCHER_PGD_INDEX (PTES_PER_PAGE - 1)
+#define SWITCHER_PGD_INDEX (PTRS_PER_PGD - 1)
 
 /* We actually need a separate PTE page for each CPU.  Remember that after the
  * Switcher code itself comes two pages for each CPU, and we don't want this
  * CPU's guest to see the pages of any other CPU. */
-static DEFINE_PER_CPU(spte_t *, switcher_pte_pages);
+static DEFINE_PER_CPU(pte_t *, switcher_pte_pages);
 #define switcher_pte_page(cpu) per_cpu(switcher_pte_pages, cpu)
 
 /*H:320 With our shadow and Guest types established, we need to deal with
  * them: the page table code is curly enough to need helper functions to keep
  * it clear and clean.
  *
- * The first helper takes a virtual address, and says which entry in the top
- * level page table deals with that address.  Since each top level entry deals
- * with 4M, this effectively divides by 4M. */
-static unsigned vaddr_to_pgd_index(unsigned long vaddr)
-{
-	return vaddr >> (PAGE_SHIFT + PTES_PER_PAGE_SHIFT);
-}
-
-/* There are two functions which return pointers to the shadow (aka "real")
+ * There are two functions which return pointers to the shadow (aka "real")
  * page tables.
  *
  * spgd_addr() takes the virtual address and returns a pointer to the top-level
  * page directory entry for that address.  Since we keep track of several page
  * tables, the "i" argument tells us which one we're interested in (it's
  * usually the current one). */
-static spgd_t *spgd_addr(struct lguest *lg, u32 i, unsigned long vaddr)
+static pgd_t *spgd_addr(struct lguest *lg, u32 i, unsigned long vaddr)
 {
-	unsigned int index = vaddr_to_pgd_index(vaddr);
+	unsigned int index = pgd_index(vaddr);
 
 	/* We kill any Guest trying to touch the Switcher addresses. */
 	if (index >= SWITCHER_PGD_INDEX) {
@@ -95,28 +84,28 @@ static spgd_t *spgd_addr(struct lguest *lg, u32 i, unsigned long vaddr)
 /* This routine then takes the PGD entry given above, which contains the
  * address of the PTE page.  It then returns a pointer to the PTE entry for the
  * given address. */
-static spte_t *spte_addr(struct lguest *lg, spgd_t spgd, unsigned long vaddr)
+static pte_t *spte_addr(struct lguest *lg, pgd_t spgd, unsigned long vaddr)
 {
-	spte_t *page = __va(spgd.pfn << PAGE_SHIFT);
+	pte_t *page = __va(pgd_pfn(spgd) << PAGE_SHIFT);
 	/* You should never call this if the PGD entry wasn't valid */
-	BUG_ON(!(spgd.flags & _PAGE_PRESENT));
-	return &page[(vaddr >> PAGE_SHIFT) % PTES_PER_PAGE];
+	BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT));
+	return &page[(vaddr >> PAGE_SHIFT) % PTRS_PER_PTE];
 }
 
 /* These two functions just like the above two, except they access the Guest
  * page tables.  Hence they return a Guest address. */
 static unsigned long gpgd_addr(struct lguest *lg, unsigned long vaddr)
 {
-	unsigned int index = vaddr >> (PAGE_SHIFT + PTES_PER_PAGE_SHIFT);
-	return lg->pgdirs[lg->pgdidx].cr3 + index * sizeof(gpgd_t);
+	unsigned int index = vaddr >> (PGDIR_SHIFT);
+	return lg->pgdirs[lg->pgdidx].gpgdir + index * sizeof(pgd_t);
 }
 
 static unsigned long gpte_addr(struct lguest *lg,
-			       gpgd_t gpgd, unsigned long vaddr)
+			       pgd_t gpgd, unsigned long vaddr)
 {
-	unsigned long gpage = gpgd.pfn << PAGE_SHIFT;
-	BUG_ON(!(gpgd.flags & _PAGE_PRESENT));
-	return gpage + ((vaddr>>PAGE_SHIFT) % PTES_PER_PAGE) * sizeof(gpte_t);
+	unsigned long gpage = pgd_pfn(gpgd) << PAGE_SHIFT;
+	BUG_ON(!(pgd_flags(gpgd) & _PAGE_PRESENT));
+	return gpage + ((vaddr>>PAGE_SHIFT) % PTRS_PER_PTE) * sizeof(pte_t);
 }
 
 /*H:350 This routine takes a page number given by the Guest and converts it to
@@ -149,53 +138,55 @@ static unsigned long get_pfn(unsigned long virtpfn, int write)
  * entry can be a little tricky.  The flags are (almost) the same, but the
  * Guest PTE contains a virtual page number: the CPU needs the real page
  * number. */
-static spte_t gpte_to_spte(struct lguest *lg, gpte_t gpte, int write)
+static pte_t gpte_to_spte(struct lguest *lg, pte_t gpte, int write)
 {
-	spte_t spte;
-	unsigned long pfn;
+	unsigned long pfn, base, flags;
 
 	/* The Guest sets the global flag, because it thinks that it is using
 	 * PGE.  We only told it to use PGE so it would tell us whether it was
 	 * flushing a kernel mapping or a userspace mapping.  We don't actually
 	 * use the global bit, so throw it away. */
-	spte.flags = (gpte.flags & ~_PAGE_GLOBAL);
+	flags = (pte_flags(gpte) & ~_PAGE_GLOBAL);
+
+	/* The Guest's pages are offset inside the Launcher. */
+	base = (unsigned long)lg->mem_base / PAGE_SIZE;
 
 	/* We need a temporary "unsigned long" variable to hold the answer from
 	 * get_pfn(), because it returns 0xFFFFFFFF on failure, which wouldn't
 	 * fit in spte.pfn.  get_pfn() finds the real physical number of the
 	 * page, given the virtual number. */
-	pfn = get_pfn(gpte.pfn, write);
+	pfn = get_pfn(base + pte_pfn(gpte), write);
 	if (pfn == -1UL) {
-		kill_guest(lg, "failed to get page %u", gpte.pfn);
+		kill_guest(lg, "failed to get page %lu", pte_pfn(gpte));
 		/* When we destroy the Guest, we'll go through the shadow page
 		 * tables and release_pte() them.  Make sure we don't think
 		 * this one is valid! */
-		spte.flags = 0;
+		flags = 0;
 	}
-	/* Now we assign the page number, and our shadow PTE is complete. */
-	spte.pfn = pfn;
-	return spte;
+	/* Now we assemble our shadow PTE from the page number and flags. */
+	return pfn_pte(pfn, __pgprot(flags));
 }
 
 /*H:460 And to complete the chain, release_pte() looks like this: */
-static void release_pte(spte_t pte)
+static void release_pte(pte_t pte)
 {
 	/* Remember that get_user_pages() took a reference to the page, in
 	 * get_pfn()?  We have to put it back now. */
-	if (pte.flags & _PAGE_PRESENT)
-		put_page(pfn_to_page(pte.pfn));
+	if (pte_flags(pte) & _PAGE_PRESENT)
+		put_page(pfn_to_page(pte_pfn(pte)));
 }
 /*:*/
 
-static void check_gpte(struct lguest *lg, gpte_t gpte)
+static void check_gpte(struct lguest *lg, pte_t gpte)
 {
-	if ((gpte.flags & (_PAGE_PWT|_PAGE_PSE)) || gpte.pfn >= lg->pfn_limit)
+	if ((pte_flags(gpte) & (_PAGE_PWT|_PAGE_PSE))
+	    || pte_pfn(gpte) >= lg->pfn_limit)
 		kill_guest(lg, "bad page table entry");
 }
 
-static void check_gpgd(struct lguest *lg, gpgd_t gpgd)
+static void check_gpgd(struct lguest *lg, pgd_t gpgd)
 {
-	if ((gpgd.flags & ~_PAGE_TABLE) || gpgd.pfn >= lg->pfn_limit)
+	if ((pgd_flags(gpgd) & ~_PAGE_TABLE) || pgd_pfn(gpgd) >= lg->pfn_limit)
 		kill_guest(lg, "bad page directory entry");
 }
 
@@ -211,21 +202,21 @@ static void check_gpgd(struct lguest *lg, gpgd_t gpgd)
  * true. */
 int demand_page(struct lguest *lg, unsigned long vaddr, int errcode)
 {
-	gpgd_t gpgd;
-	spgd_t *spgd;
+	pgd_t gpgd;
+	pgd_t *spgd;
 	unsigned long gpte_ptr;
-	gpte_t gpte;
-	spte_t *spte;
+	pte_t gpte;
+	pte_t *spte;
 
 	/* First step: get the top-level Guest page table entry. */
-	gpgd = mkgpgd(lgread_u32(lg, gpgd_addr(lg, vaddr)));
+	gpgd = lgread(lg, gpgd_addr(lg, vaddr), pgd_t);
 	/* Toplevel not present?  We can't map it in. */
-	if (!(gpgd.flags & _PAGE_PRESENT))
+	if (!(pgd_flags(gpgd) & _PAGE_PRESENT))
 		return 0;
 
 	/* Now look at the matching shadow entry. */
 	spgd = spgd_addr(lg, lg->pgdidx, vaddr);
-	if (!(spgd->flags & _PAGE_PRESENT)) {
+	if (!(pgd_flags(*spgd) & _PAGE_PRESENT)) {
 		/* No shadow entry: allocate a new shadow PTE page. */
 		unsigned long ptepage = get_zeroed_page(GFP_KERNEL);
 		/* This is not really the Guest's fault, but killing it is
@@ -238,34 +229,35 @@ int demand_page(struct lguest *lg, unsigned long vaddr, int errcode)
 		check_gpgd(lg, gpgd);
 		/* And we copy the flags to the shadow PGD entry.  The page
 		 * number in the shadow PGD is the page we just allocated. */
-		spgd->raw.val = (__pa(ptepage) | gpgd.flags);
+		*spgd = __pgd(__pa(ptepage) | pgd_flags(gpgd));
 	}
 
 	/* OK, now we look at the lower level in the Guest page table: keep its
 	 * address, because we might update it later. */
 	gpte_ptr = gpte_addr(lg, gpgd, vaddr);
-	gpte = mkgpte(lgread_u32(lg, gpte_ptr));
+	gpte = lgread(lg, gpte_ptr, pte_t);
 
 	/* If this page isn't in the Guest page tables, we can't page it in. */
-	if (!(gpte.flags & _PAGE_PRESENT))
+	if (!(pte_flags(gpte) & _PAGE_PRESENT))
 		return 0;
 
 	/* Check they're not trying to write to a page the Guest wants
 	 * read-only (bit 2 of errcode == write). */
-	if ((errcode & 2) && !(gpte.flags & _PAGE_RW))
+	if ((errcode & 2) && !(pte_flags(gpte) & _PAGE_RW))
 		return 0;
 
 	/* User access to a kernel page? (bit 3 == user access) */
-	if ((errcode & 4) && !(gpte.flags & _PAGE_USER))
+	if ((errcode & 4) && !(pte_flags(gpte) & _PAGE_USER))
 		return 0;
 
 	/* Check that the Guest PTE flags are OK, and the page number is below
 	 * the pfn_limit (ie. not mapping the Launcher binary). */
 	check_gpte(lg, gpte);
 	/* Add the _PAGE_ACCESSED and (for a write) _PAGE_DIRTY flag */
-	gpte.flags |= _PAGE_ACCESSED;
+	gpte = pte_mkyoung(gpte);
+
 	if (errcode & 2)
-		gpte.flags |= _PAGE_DIRTY;
+		gpte = pte_mkdirty(gpte);
 
 	/* Get the pointer to the shadow PTE entry we're going to set. */
 	spte = spte_addr(lg, *spgd, vaddr);
@@ -275,21 +267,18 @@ int demand_page(struct lguest *lg, unsigned long vaddr, int errcode)
 
 	/* If this is a write, we insist that the Guest page is writable (the
 	 * final arg to gpte_to_spte()). */
-	if (gpte.flags & _PAGE_DIRTY)
+	if (pte_dirty(gpte))
 		*spte = gpte_to_spte(lg, gpte, 1);
-	else {
+	else
 		/* If this is a read, don't set the "writable" bit in the page
 		 * table entry, even if the Guest says it's writable.  That way
 		 * we come back here when a write does actually ocur, so we can
 		 * update the Guest's _PAGE_DIRTY flag. */
-		gpte_t ro_gpte = gpte;
-		ro_gpte.flags &= ~_PAGE_RW;
-		*spte = gpte_to_spte(lg, ro_gpte, 0);
-	}
+		*spte = gpte_to_spte(lg, pte_wrprotect(gpte), 0);
 
 	/* Finally, we write the Guest PTE entry back: we've set the
 	 * _PAGE_ACCESSED and maybe the _PAGE_DIRTY flags. */
-	lgwrite_u32(lg, gpte_ptr, gpte.raw.val);
+	lgwrite(lg, gpte_ptr, pte_t, gpte);
 
 	/* We succeeded in mapping the page! */
 	return 1;
@@ -305,17 +294,18 @@ int demand_page(struct lguest *lg, unsigned long vaddr, int errcode)
  * mapped by the shadow page tables, and is it writable? */
 static int page_writable(struct lguest *lg, unsigned long vaddr)
 {
-	spgd_t *spgd;
+	pgd_t *spgd;
 	unsigned long flags;
 
 	/* Look at the top level entry: is it present? */
 	spgd = spgd_addr(lg, lg->pgdidx, vaddr);
-	if (!(spgd->flags & _PAGE_PRESENT))
+	if (!(pgd_flags(*spgd) & _PAGE_PRESENT))
 		return 0;
 
 	/* Check the flags on the pte entry itself: it must be present and
 	 * writable. */
-	flags = spte_addr(lg, *spgd, vaddr)->flags;
+	flags = pte_flags(*(spte_addr(lg, *spgd, vaddr)));
+
 	return (flags & (_PAGE_PRESENT|_PAGE_RW)) == (_PAGE_PRESENT|_PAGE_RW);
 }
 
@@ -329,22 +319,22 @@ void pin_page(struct lguest *lg, unsigned long vaddr)
 }
 
 /*H:450 If we chase down the release_pgd() code, it looks like this: */
-static void release_pgd(struct lguest *lg, spgd_t *spgd)
+static void release_pgd(struct lguest *lg, pgd_t *spgd)
 {
 	/* If the entry's not present, there's nothing to release. */
-	if (spgd->flags & _PAGE_PRESENT) {
+	if (pgd_flags(*spgd) & _PAGE_PRESENT) {
 		unsigned int i;
 		/* Converting the pfn to find the actual PTE page is easy: turn
 		 * the page number into a physical address, then convert to a
 		 * virtual address (easy for kernel pages like this one). */
-		spte_t *ptepage = __va(spgd->pfn << PAGE_SHIFT);
+		pte_t *ptepage = __va(pgd_pfn(*spgd) << PAGE_SHIFT);
 		/* For each entry in the page, we might need to release it. */
-		for (i = 0; i < PTES_PER_PAGE; i++)
+		for (i = 0; i < PTRS_PER_PTE; i++)
 			release_pte(ptepage[i]);
 		/* Now we can free the page of PTEs */
 		free_page((long)ptepage);
 		/* And zero out the PGD entry we we never release it twice. */
-		spgd->raw.val = 0;
+		*spgd = __pgd(0);
 	}
 }
 
@@ -356,7 +346,7 @@ static void flush_user_mappings(struct lguest *lg, int idx)
 {
 	unsigned int i;
 	/* Release every pgd entry up to the kernel's address. */
-	for (i = 0; i < vaddr_to_pgd_index(lg->page_offset); i++)
+	for (i = 0; i < pgd_index(lg->kernel_address); i++)
 		release_pgd(lg, lg->pgdirs[idx].pgdir + i);
 }
 
@@ -369,6 +359,25 @@ void guest_pagetable_flush_user(struct lguest *lg)
 }
 /*:*/
 
+/* We walk down the guest page tables to get a guest-physical address */
+unsigned long guest_pa(struct lguest *lg, unsigned long vaddr)
+{
+	pgd_t gpgd;
+	pte_t gpte;
+
+	/* First step: get the top-level Guest page table entry. */
+	gpgd = lgread(lg, gpgd_addr(lg, vaddr), pgd_t);
+	/* Toplevel not present?  We can't map it in. */
+	if (!(pgd_flags(gpgd) & _PAGE_PRESENT))
+		kill_guest(lg, "Bad address %#lx", vaddr);
+
+	gpte = lgread(lg, gpte_addr(lg, gpgd, vaddr), pte_t);
+	if (!(pte_flags(gpte) & _PAGE_PRESENT))
+		kill_guest(lg, "Bad address %#lx", vaddr);
+
+	return pte_pfn(gpte) * PAGE_SIZE | (vaddr & ~PAGE_MASK);
+}
+
 /* We keep several page tables.  This is a simple routine to find the page
  * table (if any) corresponding to this top-level address the Guest has given
  * us. */
@@ -376,7 +385,7 @@ static unsigned int find_pgdir(struct lguest *lg, unsigned long pgtable)
 {
 	unsigned int i;
 	for (i = 0; i < ARRAY_SIZE(lg->pgdirs); i++)
-		if (lg->pgdirs[i].cr3 == pgtable)
+		if (lg->pgdirs[i].gpgdir == pgtable)
 			break;
 	return i;
 }
@@ -385,7 +394,7 @@ static unsigned int find_pgdir(struct lguest *lg, unsigned long pgtable)
  * allocate a new one (and so the kernel parts are not there), we set
  * blank_pgdir. */
 static unsigned int new_pgdir(struct lguest *lg,
-			      unsigned long cr3,
+			      unsigned long gpgdir,
 			      int *blank_pgdir)
 {
 	unsigned int next;
@@ -395,7 +404,7 @@ static unsigned int new_pgdir(struct lguest *lg,
 	next = random32() % ARRAY_SIZE(lg->pgdirs);
 	/* If it's never been allocated at all before, try now. */
 	if (!lg->pgdirs[next].pgdir) {
-		lg->pgdirs[next].pgdir = (spgd_t *)get_zeroed_page(GFP_KERNEL);
+		lg->pgdirs[next].pgdir = (pgd_t *)get_zeroed_page(GFP_KERNEL);
 		/* If the allocation fails, just keep using the one we have */
 		if (!lg->pgdirs[next].pgdir)
 			next = lg->pgdidx;
@@ -405,7 +414,7 @@ static unsigned int new_pgdir(struct lguest *lg,
 			*blank_pgdir = 1;
 	}
 	/* Record which Guest toplevel this shadows. */
-	lg->pgdirs[next].cr3 = cr3;
+	lg->pgdirs[next].gpgdir = gpgdir;
 	/* Release all the non-kernel mappings. */
 	flush_user_mappings(lg, next);
 
@@ -472,26 +481,27 @@ void guest_pagetable_clear_all(struct lguest *lg)
  * they set _PAGE_DIRTY then we can put a writable PTE entry in immediately.
  */
 static void do_set_pte(struct lguest *lg, int idx,
-		       unsigned long vaddr, gpte_t gpte)
+		       unsigned long vaddr, pte_t gpte)
 {
 	/* Look up the matching shadow page directot entry. */
-	spgd_t *spgd = spgd_addr(lg, idx, vaddr);
+	pgd_t *spgd = spgd_addr(lg, idx, vaddr);
 
 	/* If the top level isn't present, there's no entry to update. */
-	if (spgd->flags & _PAGE_PRESENT) {
+	if (pgd_flags(*spgd) & _PAGE_PRESENT) {
 		/* Otherwise, we start by releasing the existing entry. */
-		spte_t *spte = spte_addr(lg, *spgd, vaddr);
+		pte_t *spte = spte_addr(lg, *spgd, vaddr);
 		release_pte(*spte);
 
 		/* If they're setting this entry as dirty or accessed, we might
 		 * as well put that entry they've given us in now.  This shaves
 		 * 10% off a copy-on-write micro-benchmark. */
-		if (gpte.flags & (_PAGE_DIRTY | _PAGE_ACCESSED)) {
+		if (pte_flags(gpte) & (_PAGE_DIRTY | _PAGE_ACCESSED)) {
 			check_gpte(lg, gpte);
-			*spte = gpte_to_spte(lg, gpte, gpte.flags&_PAGE_DIRTY);
+			*spte = gpte_to_spte(lg, gpte,
+					     pte_flags(gpte) & _PAGE_DIRTY);
 		} else
 			/* Otherwise we can demand_page() it in later. */
-			spte->raw.val = 0;
+			*spte = __pte(0);
 	}
 }
 
@@ -506,18 +516,18 @@ static void do_set_pte(struct lguest *lg, int idx,
  * The benefit is that when we have to track a new page table, we can copy keep
  * all the kernel mappings.  This speeds up context switch immensely. */
 void guest_set_pte(struct lguest *lg,
-		   unsigned long cr3, unsigned long vaddr, gpte_t gpte)
+		   unsigned long gpgdir, unsigned long vaddr, pte_t gpte)
 {
 	/* Kernel mappings must be changed on all top levels.  Slow, but
 	 * doesn't happen often. */
-	if (vaddr >= lg->page_offset) {
+	if (vaddr >= lg->kernel_address) {
 		unsigned int i;
 		for (i = 0; i < ARRAY_SIZE(lg->pgdirs); i++)
 			if (lg->pgdirs[i].pgdir)
 				do_set_pte(lg, i, vaddr, gpte);
 	} else {
 		/* Is this page table one we have a shadow for? */
-		int pgdir = find_pgdir(lg, cr3);
+		int pgdir = find_pgdir(lg, gpgdir);
 		if (pgdir != ARRAY_SIZE(lg->pgdirs))
 			/* If so, do the update. */
 			do_set_pte(lg, pgdir, vaddr, gpte);
@@ -538,7 +548,7 @@ void guest_set_pte(struct lguest *lg,
  *
  * So with that in mind here's our code to to update a (top-level) PGD entry:
  */
-void guest_set_pmd(struct lguest *lg, unsigned long cr3, u32 idx)
+void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 idx)
 {
 	int pgdir;
 
@@ -548,7 +558,7 @@ void guest_set_pmd(struct lguest *lg, unsigned long cr3, u32 idx)
 		return;
 
 	/* If they're talking about a page table we have a shadow for... */
-	pgdir = find_pgdir(lg, cr3);
+	pgdir = find_pgdir(lg, gpgdir);
 	if (pgdir < ARRAY_SIZE(lg->pgdirs))
 		/* ... throw it away. */
 		release_pgd(lg, lg->pgdirs[pgdir].pgdir + idx);
@@ -560,21 +570,34 @@ void guest_set_pmd(struct lguest *lg, unsigned long cr3, u32 idx)
  * its first page table is.  We set some things up here: */
 int init_guest_pagetable(struct lguest *lg, unsigned long pgtable)
 {
-	/* In flush_user_mappings() we loop from 0 to
-	 * "vaddr_to_pgd_index(lg->page_offset)".  This assumes it won't hit
-	 * the Switcher mappings, so check that now. */
-	if (vaddr_to_pgd_index(lg->page_offset) >= SWITCHER_PGD_INDEX)
-		return -EINVAL;
 	/* We start on the first shadow page table, and give it a blank PGD
 	 * page. */
 	lg->pgdidx = 0;
-	lg->pgdirs[lg->pgdidx].cr3 = pgtable;
-	lg->pgdirs[lg->pgdidx].pgdir = (spgd_t*)get_zeroed_page(GFP_KERNEL);
+	lg->pgdirs[lg->pgdidx].gpgdir = pgtable;
+	lg->pgdirs[lg->pgdidx].pgdir = (pgd_t*)get_zeroed_page(GFP_KERNEL);
 	if (!lg->pgdirs[lg->pgdidx].pgdir)
 		return -ENOMEM;
 	return 0;
 }
 
+/* When the Guest calls LHCALL_LGUEST_INIT we do more setup. */
+void page_table_guest_data_init(struct lguest *lg)
+{
+	/* We get the kernel address: above this is all kernel memory. */
+	if (get_user(lg->kernel_address, &lg->lguest_data->kernel_address)
+	    /* We tell the Guest that it can't use the top 4MB of virtual
+	     * addresses used by the Switcher. */
+	    || put_user(4U*1024*1024, &lg->lguest_data->reserve_mem)
+	    || put_user(lg->pgdirs[lg->pgdidx].gpgdir,&lg->lguest_data->pgdir))
+		kill_guest(lg, "bad guest page %p", lg->lguest_data);
+
+	/* In flush_user_mappings() we loop from 0 to
+	 * "pgd_index(lg->kernel_address)".  This assumes it won't hit the
+	 * Switcher mappings, so check that now. */
+	if (pgd_index(lg->kernel_address) >= SWITCHER_PGD_INDEX)
+		kill_guest(lg, "bad kernel address %#lx", lg->kernel_address);
+}
+
 /* When a Guest dies, our cleanup is fairly simple. */
 void free_guest_pagetable(struct lguest *lg)
 {
@@ -594,14 +617,14 @@ void free_guest_pagetable(struct lguest *lg)
  * for each CPU already set up, we just need to hook them in. */
 void map_switcher_in_guest(struct lguest *lg, struct lguest_pages *pages)
 {
-	spte_t *switcher_pte_page = __get_cpu_var(switcher_pte_pages);
-	spgd_t switcher_pgd;
-	spte_t regs_pte;
+	pte_t *switcher_pte_page = __get_cpu_var(switcher_pte_pages);
+	pgd_t switcher_pgd;
+	pte_t regs_pte;
 
 	/* Make the last PGD entry for this Guest point to the Switcher's PTE
 	 * page for this CPU (with appropriate flags). */
-	switcher_pgd.pfn = __pa(switcher_pte_page) >> PAGE_SHIFT;
-	switcher_pgd.flags = _PAGE_KERNEL;
+	switcher_pgd = __pgd(__pa(switcher_pte_page) | _PAGE_KERNEL);
+
 	lg->pgdirs[lg->pgdidx].pgdir[SWITCHER_PGD_INDEX] = switcher_pgd;
 
 	/* We also change the Switcher PTE page.  When we're running the Guest,
@@ -611,10 +634,8 @@ void map_switcher_in_guest(struct lguest *lg, struct lguest_pages *pages)
 	 * CPU's "struct lguest_pages": if we make sure the Guest's register
 	 * page is already mapped there, we don't have to copy them out
 	 * again. */
-	regs_pte.pfn = __pa(lg->regs_page) >> PAGE_SHIFT;
-	regs_pte.flags = _PAGE_KERNEL;
-	switcher_pte_page[(unsigned long)pages/PAGE_SIZE%PTES_PER_PAGE]
-		= regs_pte;
+	regs_pte = pfn_pte (__pa(lg->regs_page) >> PAGE_SHIFT, __pgprot(_PAGE_KERNEL));
+	switcher_pte_page[(unsigned long)pages/PAGE_SIZE%PTRS_PER_PTE] = regs_pte;
 }
 /*:*/
 
@@ -635,24 +656,25 @@ static __init void populate_switcher_pte_page(unsigned int cpu,
 					      unsigned int pages)
 {
 	unsigned int i;
-	spte_t *pte = switcher_pte_page(cpu);
+	pte_t *pte = switcher_pte_page(cpu);
 
 	/* The first entries are easy: they map the Switcher code. */
 	for (i = 0; i < pages; i++) {
-		pte[i].pfn = page_to_pfn(switcher_page[i]);
-		pte[i].flags = _PAGE_PRESENT|_PAGE_ACCESSED;
+		pte[i] = mk_pte(switcher_page[i],
+				__pgprot(_PAGE_PRESENT|_PAGE_ACCESSED));
 	}
 
 	/* The only other thing we map is this CPU's pair of pages. */
 	i = pages + cpu*2;
 
 	/* First page (Guest registers) is writable from the Guest */
-	pte[i].pfn = page_to_pfn(switcher_page[i]);
-	pte[i].flags = _PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_RW;
+	pte[i] = pfn_pte(page_to_pfn(switcher_page[i]),
+			 __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_RW));
+
 	/* The second page contains the "struct lguest_ro_state", and is
 	 * read-only. */
-	pte[i+1].pfn = page_to_pfn(switcher_page[i+1]);
-	pte[i+1].flags = _PAGE_PRESENT|_PAGE_ACCESSED;
+	pte[i+1] = pfn_pte(page_to_pfn(switcher_page[i+1]),
+			   __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED));
 }
 
 /*H:510 At boot or module load time, init_pagetables() allocates and populates
@@ -662,7 +684,7 @@ __init int init_pagetables(struct page **switcher_page, unsigned int pages)
 	unsigned int i;
 
 	for_each_possible_cpu(i) {
-		switcher_pte_page(i) = (spte_t *)get_zeroed_page(GFP_KERNEL);
+		switcher_pte_page(i) = (pte_t *)get_zeroed_page(GFP_KERNEL);
 		if (!switcher_pte_page(i)) {
 			free_switcher_pte_pages();
 			return -ENOMEM;
diff --git a/drivers/lguest/segments.c b/drivers/lguest/segments.c
index 9b81119..c2434ec 100644
--- a/drivers/lguest/segments.c
+++ b/drivers/lguest/segments.c
@@ -73,14 +73,14 @@ static void fixup_gdt_table(struct lguest *lg, unsigned start, unsigned end)
 		/* Segment descriptors contain a privilege level: the Guest is
 		 * sometimes careless and leaves this as 0, even though it's
 		 * running at privilege level 1.  If so, we fix it here. */
-		if ((lg->gdt[i].b & 0x00006000) == 0)
-			lg->gdt[i].b |= (GUEST_PL << 13);
+		if ((lg->arch.gdt[i].b & 0x00006000) == 0)
+			lg->arch.gdt[i].b |= (GUEST_PL << 13);
 
 		/* Each descriptor has an "accessed" bit.  If we don't set it
 		 * now, the CPU will try to set it when the Guest first loads
 		 * that entry into a segment register.  But the GDT isn't
 		 * writable by the Guest, so bad things can happen. */
-		lg->gdt[i].b |= 0x00000100;
+		lg->arch.gdt[i].b |= 0x00000100;
 	}
 }
 
@@ -106,12 +106,12 @@ void setup_default_gdt_entries(struct lguest_ro_state *state)
 void setup_guest_gdt(struct lguest *lg)
 {
 	/* Start with full 0-4G segments... */
-	lg->gdt[GDT_ENTRY_KERNEL_CS] = FULL_EXEC_SEGMENT;
-	lg->gdt[GDT_ENTRY_KERNEL_DS] = FULL_SEGMENT;
+	lg->arch.gdt[GDT_ENTRY_KERNEL_CS] = FULL_EXEC_SEGMENT;
+	lg->arch.gdt[GDT_ENTRY_KERNEL_DS] = FULL_SEGMENT;
 	/* ...except the Guest is allowed to use them, so set the privilege
 	 * level appropriately in the flags. */
-	lg->gdt[GDT_ENTRY_KERNEL_CS].b |= (GUEST_PL << 13);
-	lg->gdt[GDT_ENTRY_KERNEL_DS].b |= (GUEST_PL << 13);
+	lg->arch.gdt[GDT_ENTRY_KERNEL_CS].b |= (GUEST_PL << 13);
+	lg->arch.gdt[GDT_ENTRY_KERNEL_DS].b |= (GUEST_PL << 13);
 }
 
 /* Like the IDT, we never simply use the GDT the Guest gives us.  We set up the
@@ -126,7 +126,7 @@ void copy_gdt_tls(const struct lguest *lg, struct desc_struct *gdt)
 	unsigned int i;
 
 	for (i = GDT_ENTRY_TLS_MIN; i <= GDT_ENTRY_TLS_MAX; i++)
-		gdt[i] = lg->gdt[i];
+		gdt[i] = lg->arch.gdt[i];
 }
 
 /* This is the full version */
@@ -138,7 +138,7 @@ void copy_gdt(const struct lguest *lg, struct desc_struct *gdt)
 	 * replaced.  See ignored_gdt() above. */
 	for (i = 0; i < GDT_ENTRIES; i++)
 		if (!ignored_gdt(i))
-			gdt[i] = lg->gdt[i];
+			gdt[i] = lg->arch.gdt[i];
 }
 
 /* This is where the Guest asks us to load a new GDT (LHCALL_LOAD_GDT). */
@@ -146,12 +146,12 @@ void load_guest_gdt(struct lguest *lg, unsigned long table, u32 num)
 {
 	/* We assume the Guest has the same number of GDT entries as the
 	 * Host, otherwise we'd have to dynamically allocate the Guest GDT. */
-	if (num > ARRAY_SIZE(lg->gdt))
+	if (num > ARRAY_SIZE(lg->arch.gdt))
 		kill_guest(lg, "too many gdt entries %i", num);
 
 	/* We read the whole thing in, then fix it up. */
-	lgread(lg, lg->gdt, table, num * sizeof(lg->gdt[0]));
-	fixup_gdt_table(lg, 0, ARRAY_SIZE(lg->gdt));
+	__lgread(lg, lg->arch.gdt, table, num * sizeof(lg->arch.gdt[0]));
+	fixup_gdt_table(lg, 0, ARRAY_SIZE(lg->arch.gdt));
 	/* Mark that the GDT changed so the core knows it has to copy it again,
 	 * even if the Guest is run on the same CPU. */
 	lg->changed |= CHANGED_GDT;
@@ -159,9 +159,9 @@ void load_guest_gdt(struct lguest *lg, unsigned long table, u32 num)
 
 void guest_load_tls(struct lguest *lg, unsigned long gtls)
 {
-	struct desc_struct *tls = &lg->gdt[GDT_ENTRY_TLS_MIN];
+	struct desc_struct *tls = &lg->arch.gdt[GDT_ENTRY_TLS_MIN];
 
-	lgread(lg, tls, gtls, sizeof(*tls)*GDT_ENTRY_TLS_ENTRIES);
+	__lgread(lg, tls, gtls, sizeof(*tls)*GDT_ENTRY_TLS_ENTRIES);
 	fixup_gdt_table(lg, GDT_ENTRY_TLS_MIN, GDT_ENTRY_TLS_MAX+1);
 	lg->changed |= CHANGED_GDT_TLS;
 }
diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
new file mode 100644
index 0000000..9eed12d
--- /dev/null
+++ b/drivers/lguest/x86/core.c
@@ -0,0 +1,577 @@
+/*
+ * Copyright (C) 2006, Rusty Russell <rusty@rustcorp.com.au> IBM Corporation.
+ * Copyright (C) 2007, Jes Sorensen <jes@sgi.com> SGI.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <linux/kernel.h>
+#include <linux/start_kernel.h>
+#include <linux/string.h>
+#include <linux/console.h>
+#include <linux/screen_info.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/cpu.h>
+#include <linux/lguest.h>
+#include <linux/lguest_launcher.h>
+#include <asm/paravirt.h>
+#include <asm/param.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/desc.h>
+#include <asm/setup.h>
+#include <asm/lguest.h>
+#include <asm/uaccess.h>
+#include <asm/i387.h>
+#include "../lg.h"
+
+static int cpu_had_pge;
+
+static struct {
+	unsigned long offset;
+	unsigned short segment;
+} lguest_entry;
+
+/* Offset from where switcher.S was compiled to where we've copied it */
+static unsigned long switcher_offset(void)
+{
+	return SWITCHER_ADDR - (unsigned long)start_switcher_text;
+}
+
+/* This cpu's struct lguest_pages. */
+static struct lguest_pages *lguest_pages(unsigned int cpu)
+{
+	return &(((struct lguest_pages *)
+		  (SWITCHER_ADDR + SHARED_SWITCHER_PAGES*PAGE_SIZE))[cpu]);
+}
+
+static DEFINE_PER_CPU(struct lguest *, last_guest);
+
+/*S:010
+ * We are getting close to the Switcher.
+ *
+ * Remember that each CPU has two pages which are visible to the Guest when it
+ * runs on that CPU.  This has to contain the state for that Guest: we copy the
+ * state in just before we run the Guest.
+ *
+ * Each Guest has "changed" flags which indicate what has changed in the Guest
+ * since it last ran.  We saw this set in interrupts_and_traps.c and
+ * segments.c.
+ */
+static void copy_in_guest_info(struct lguest *lg, struct lguest_pages *pages)
+{
+	/* Copying all this data can be quite expensive.  We usually run the
+	 * same Guest we ran last time (and that Guest hasn't run anywhere else
+	 * meanwhile).  If that's not the case, we pretend everything in the
+	 * Guest has changed. */
+	if (__get_cpu_var(last_guest) != lg || lg->last_pages != pages) {
+		__get_cpu_var(last_guest) = lg;
+		lg->last_pages = pages;
+		lg->changed = CHANGED_ALL;
+	}
+
+	/* These copies are pretty cheap, so we do them unconditionally: */
+	/* Save the current Host top-level page directory. */
+	pages->state.host_cr3 = __pa(current->mm->pgd);
+	/* Set up the Guest's page tables to see this CPU's pages (and no
+	 * other CPU's pages). */
+	map_switcher_in_guest(lg, pages);
+	/* Set up the two "TSS" members which tell the CPU what stack to use
+	 * for traps which do directly into the Guest (ie. traps at privilege
+	 * level 1). */
+	pages->state.guest_tss.esp1 = lg->esp1;
+	pages->state.guest_tss.ss1 = lg->ss1;
+
+	/* Copy direct-to-Guest trap entries. */
+	if (lg->changed & CHANGED_IDT)
+		copy_traps(lg, pages->state.guest_idt, default_idt_entries);
+
+	/* Copy all GDT entries which the Guest can change. */
+	if (lg->changed & CHANGED_GDT)
+		copy_gdt(lg, pages->state.guest_gdt);
+	/* If only the TLS entries have changed, copy them. */
+	else if (lg->changed & CHANGED_GDT_TLS)
+		copy_gdt_tls(lg, pages->state.guest_gdt);
+
+	/* Mark the Guest as unchanged for next time. */
+	lg->changed = 0;
+}
+
+/* Finally: the code to actually call into the Switcher to run the Guest. */
+static void run_guest_once(struct lguest *lg, struct lguest_pages *pages)
+{
+	/* This is a dummy value we need for GCC's sake. */
+	unsigned int clobber;
+
+	/* Copy the guest-specific information into this CPU's "struct
+	 * lguest_pages". */
+	copy_in_guest_info(lg, pages);
+
+	/* Set the trap number to 256 (impossible value).  If we fault while
+	 * switching to the Guest (bad segment registers or bug), this will
+	 * cause us to abort the Guest. */
+	lg->regs->trapnum = 256;
+
+	/* Now: we push the "eflags" register on the stack, then do an "lcall".
+	 * This is how we change from using the kernel code segment to using
+	 * the dedicated lguest code segment, as well as jumping into the
+	 * Switcher.
+	 *
+	 * The lcall also pushes the old code segment (KERNEL_CS) onto the
+	 * stack, then the address of this call.  This stack layout happens to
+	 * exactly match the stack of an interrupt... */
+	asm volatile("pushf; lcall *lguest_entry"
+		     /* This is how we tell GCC that %eax ("a") and %ebx ("b")
+		      * are changed by this routine.  The "=" means output. */
+		     : "=a"(clobber), "=b"(clobber)
+		     /* %eax contains the pages pointer.  ("0" refers to the
+		      * 0-th argument above, ie "a").  %ebx contains the
+		      * physical address of the Guest's top-level page
+		      * directory. */
+		     : "0"(pages), "1"(__pa(lg->pgdirs[lg->pgdidx].pgdir))
+		     /* We tell gcc that all these registers could change,
+		      * which means we don't have to save and restore them in
+		      * the Switcher. */
+		     : "memory", "%edx", "%ecx", "%edi", "%esi");
+}
+/*:*/
+
+/*H:040 This is the i386-specific code to setup and run the Guest.  Interrupts
+ * are disabled: we own the CPU. */
+void lguest_arch_run_guest(struct lguest *lg)
+{
+	/* Remember the awfully-named TS bit?  If the Guest has asked
+	 * to set it we set it now, so we can trap and pass that trap
+	 * to the Guest if it uses the FPU. */
+	if (lg->ts)
+		lguest_set_ts();
+
+	/* SYSENTER is an optimized way of doing system calls.  We
+	 * can't allow it because it always jumps to privilege level 0.
+	 * A normal Guest won't try it because we don't advertise it in
+	 * CPUID, but a malicious Guest (or malicious Guest userspace
+	 * program) could, so we tell the CPU to disable it before
+	 * running the Guest. */
+	if (boot_cpu_has(X86_FEATURE_SEP))
+		wrmsr(MSR_IA32_SYSENTER_CS, 0, 0);
+
+	/* Now we actually run the Guest.  It will pop back out when
+	 * something interesting happens, and we can examine its
+	 * registers to see what it was doing. */
+	run_guest_once(lg, lguest_pages(raw_smp_processor_id()));
+
+	/* The "regs" pointer contains two extra entries which are not
+	 * really registers: a trap number which says what interrupt or
+	 * trap made the switcher code come back, and an error code
+	 * which some traps set.  */
+
+	/* If the Guest page faulted, then the cr2 register will tell
+	 * us the bad virtual address.  We have to grab this now,
+	 * because once we re-enable interrupts an interrupt could
+	 * fault and thus overwrite cr2, or we could even move off to a
+	 * different CPU. */
+	if (lg->regs->trapnum == 14)
+		lg->arch.last_pagefault = read_cr2();
+	/* Similarly, if we took a trap because the Guest used the FPU,
+	 * we have to restore the FPU it expects to see. */
+	else if (lg->regs->trapnum == 7)
+		math_state_restore();
+
+	/* Restore SYSENTER if it's supposed to be on. */
+	if (boot_cpu_has(X86_FEATURE_SEP))
+		wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
+}
+
+/*H:130 Our Guest is usually so well behaved; it never tries to do things it
+ * isn't allowed to.  Unfortunately, Linux's paravirtual infrastructure isn't
+ * quite complete, because it doesn't contain replacements for the Intel I/O
+ * instructions.  As a result, the Guest sometimes fumbles across one during
+ * the boot process as it probes for various things which are usually attached
+ * to a PC.
+ *
+ * When the Guest uses one of these instructions, we get trap #13 (General
+ * Protection Fault) and come here.  We see if it's one of those troublesome
+ * instructions and skip over it.  We return true if we did. */
+static int emulate_insn(struct lguest *lg)
+{
+	u8 insn;
+	unsigned int insnlen = 0, in = 0, shift = 0;
+	/* The eip contains the *virtual* address of the Guest's instruction:
+	 * guest_pa just subtracts the Guest's page_offset. */
+	unsigned long physaddr = guest_pa(lg, lg->regs->eip);
+
+	/* This must be the Guest kernel trying to do something, not userspace!
+	 * The bottom two bits of the CS segment register are the privilege
+	 * level. */
+	if ((lg->regs->cs & 3) != GUEST_PL)
+		return 0;
+
+	/* Decoding x86 instructions is icky. */
+	insn = lgread(lg, physaddr, u8);
+
+	/* 0x66 is an "operand prefix".  It means it's using the upper 16 bits
+	   of the eax register. */
+	if (insn == 0x66) {
+		shift = 16;
+		/* The instruction is 1 byte so far, read the next byte. */
+		insnlen = 1;
+		insn = lgread(lg, physaddr + insnlen, u8);
+	}
+
+	/* We can ignore the lower bit for the moment and decode the 4 opcodes
+	 * we need to emulate. */
+	switch (insn & 0xFE) {
+	case 0xE4: /* in     <next byte>,%al */
+		insnlen += 2;
+		in = 1;
+		break;
+	case 0xEC: /* in     (%dx),%al */
+		insnlen += 1;
+		in = 1;
+		break;
+	case 0xE6: /* out    %al,<next byte> */
+		insnlen += 2;
+		break;
+	case 0xEE: /* out    %al,(%dx) */
+		insnlen += 1;
+		break;
+	default:
+		/* OK, we don't know what this is, can't emulate. */
+		return 0;
+	}
+
+	/* If it was an "IN" instruction, they expect the result to be read
+	 * into %eax, so we change %eax.  We always return all-ones, which
+	 * traditionally means "there's nothing there". */
+	if (in) {
+		/* Lower bit tells is whether it's a 16 or 32 bit access */
+		if (insn & 0x1)
+			lg->regs->eax = 0xFFFFFFFF;
+		else
+			lg->regs->eax |= (0xFFFF << shift);
+	}
+	/* Finally, we've "done" the instruction, so move past it. */
+	lg->regs->eip += insnlen;
+	/* Success! */
+	return 1;
+}
+
+/*H:050 Once we've re-enabled interrupts, we look at why the Guest exited. */
+void lguest_arch_handle_trap(struct lguest *lg)
+{
+	switch (lg->regs->trapnum) {
+	case 13: /* We've intercepted a GPF. */
+		 /* Check if this was one of those annoying IN or OUT
+		  * instructions which we need to emulate.  If so, we
+		  * just go back into the Guest after we've done it. */
+		if (lg->regs->errcode == 0) {
+			if (emulate_insn(lg))
+				return;
+		}
+		break;
+	case 14: /* We've intercepted a page fault. */
+		 /* The Guest accessed a virtual address that wasn't
+		  * mapped.  This happens a lot: we don't actually set
+		  * up most of the page tables for the Guest at all when
+		  * we start: as it runs it asks for more and more, and
+		  * we set them up as required. In this case, we don't
+		  * even tell the Guest that the fault happened.
+		  *
+		  * The errcode tells whether this was a read or a
+		  * write, and whether kernel or userspace code. */
+		if (demand_page(lg, lg->arch.last_pagefault, lg->regs->errcode))
+			return;
+
+		 /* OK, it's really not there (or not OK): the Guest
+		  * needs to know.  We write out the cr2 value so it
+		  * knows where the fault occurred.
+		  *
+		  * Note that if the Guest were really messed up, this
+		  * could happen before it's done the INITIALIZE
+		  * hypercall, so lg->lguest_data will be NULL */
+		if (lg->lguest_data &&
+		    put_user(lg->arch.last_pagefault, &lg->lguest_data->cr2))
+			kill_guest(lg, "Writing cr2");
+		break;
+	case 7: /* We've intercepted a Device Not Available fault. */
+		/* If the Guest doesn't want to know, we already
+		 * restored the Floating Point Unit, so we just
+		 * continue without telling it. */
+		if (!lg->ts)
+			return;
+		break;
+	case 32 ... 255:
+		/* These values mean a real interrupt occurred, in which case
+		 * the Host handler has already been run.  We just do a
+		 * friendly check if another process should now be run, then
+		 * return to run the Guest again */
+		cond_resched();
+		return;
+	case LGUEST_TRAP_ENTRY:
+		/* Our 'struct hcall_args' maps directly over our regs: we set
+		 * up the pointer now to indicate a hypercall is pending. */
+		lg->hcall = (struct hcall_args *)lg->regs;
+		return;
+	}
+
+	/* We didn't handle the trap, so it needs to go to the Guest. */
+	if (!deliver_trap(lg, lg->regs->trapnum))
+		/* If the Guest doesn't have a handler (either it hasn't
+		 * registered any yet, or it's one of the faults we don't let
+		 * it handle), it dies with a cryptic error message. */
+		kill_guest(lg, "unhandled trap %li at %#lx (%#lx)",
+			   lg->regs->trapnum, lg->regs->eip,
+			   lg->regs->trapnum == 14 ? lg->arch.last_pagefault
+			   : lg->regs->errcode);
+}
+
+/* Now we can look at each of the routines this calls, in increasing order of
+ * complexity: do_hypercalls(), emulate_insn(), maybe_do_interrupt(),
+ * deliver_trap() and demand_page().  After all those, we'll be ready to
+ * examine the Switcher, and our philosophical understanding of the Host/Guest
+ * duality will be complete. :*/
+static void adjust_pge(void *on)
+{
+	if (on)
+		write_cr4(read_cr4() | X86_CR4_PGE);
+	else
+		write_cr4(read_cr4() & ~X86_CR4_PGE);
+}
+
+/*H:020 Now the Switcher is mapped and every thing else is ready, we need to do
+ * some more i386-specific initialization. */
+void __init lguest_arch_host_init(void)
+{
+	int i;
+
+	/* Most of the i386/switcher.S doesn't care that it's been moved; on
+	 * Intel, jumps are relative, and it doesn't access any references to
+	 * external code or data.
+	 *
+	 * The only exception is the interrupt handlers in switcher.S: their
+	 * addresses are placed in a table (default_idt_entries), so we need to
+	 * update the table with the new addresses.  switcher_offset() is a
+	 * convenience function which returns the distance between the builtin
+	 * switcher code and the high-mapped copy we just made. */
+	for (i = 0; i < IDT_ENTRIES; i++)
+		default_idt_entries[i] += switcher_offset();
+
+	/*
+	 * Set up the Switcher's per-cpu areas.
+	 *
+	 * Each CPU gets two pages of its own within the high-mapped region
+	 * (aka. "struct lguest_pages").  Much of this can be initialized now,
+	 * but some depends on what Guest we are running (which is set up in
+	 * copy_in_guest_info()).
+	 */
+	for_each_possible_cpu(i) {
+		/* lguest_pages() returns this CPU's two pages. */
+		struct lguest_pages *pages = lguest_pages(i);
+		/* This is a convenience pointer to make the code fit one
+		 * statement to a line. */
+		struct lguest_ro_state *state = &pages->state;
+
+		/* The Global Descriptor Table: the Host has a different one
+		 * for each CPU.  We keep a descriptor for the GDT which says
+		 * where it is and how big it is (the size is actually the last
+		 * byte, not the size, hence the "-1"). */
+		state->host_gdt_desc.size = GDT_SIZE-1;
+		state->host_gdt_desc.address = (long)get_cpu_gdt_table(i);
+
+		/* All CPUs on the Host use the same Interrupt Descriptor
+		 * Table, so we just use store_idt(), which gets this CPU's IDT
+		 * descriptor. */
+		store_idt(&state->host_idt_desc);
+
+		/* The descriptors for the Guest's GDT and IDT can be filled
+		 * out now, too.  We copy the GDT & IDT into ->guest_gdt and
+		 * ->guest_idt before actually running the Guest. */
+		state->guest_idt_desc.size = sizeof(state->guest_idt)-1;
+		state->guest_idt_desc.address = (long)&state->guest_idt;
+		state->guest_gdt_desc.size = sizeof(state->guest_gdt)-1;
+		state->guest_gdt_desc.address = (long)&state->guest_gdt;
+
+		/* We know where we want the stack to be when the Guest enters
+		 * the switcher: in pages->regs.  The stack grows upwards, so
+		 * we start it at the end of that structure. */
+		state->guest_tss.esp0 = (long)(&pages->regs + 1);
+		/* And this is the GDT entry to use for the stack: we keep a
+		 * couple of special LGUEST entries. */
+		state->guest_tss.ss0 = LGUEST_DS;
+
+		/* x86 can have a finegrained bitmap which indicates what I/O
+		 * ports the process can use.  We set it to the end of our
+		 * structure, meaning "none". */
+		state->guest_tss.io_bitmap_base = sizeof(state->guest_tss);
+
+		/* Some GDT entries are the same across all Guests, so we can
+		 * set them up now. */
+		setup_default_gdt_entries(state);
+		/* Most IDT entries are the same for all Guests, too.*/
+		setup_default_idt_entries(state, default_idt_entries);
+
+		/* The Host needs to be able to use the LGUEST segments on this
+		 * CPU, too, so put them in the Host GDT. */
+		get_cpu_gdt_table(i)[GDT_ENTRY_LGUEST_CS] = FULL_EXEC_SEGMENT;
+		get_cpu_gdt_table(i)[GDT_ENTRY_LGUEST_DS] = FULL_SEGMENT;
+	}
+
+	/* In the Switcher, we want the %cs segment register to use the
+	 * LGUEST_CS GDT entry: we've put that in the Host and Guest GDTs, so
+	 * it will be undisturbed when we switch.  To change %cs and jump we
+	 * need this structure to feed to Intel's "lcall" instruction. */
+	lguest_entry.offset = (long)switch_to_guest + switcher_offset();
+	lguest_entry.segment = LGUEST_CS;
+
+	/* Finally, we need to turn off "Page Global Enable".  PGE is an
+	 * optimization where page table entries are specially marked to show
+	 * they never change.  The Host kernel marks all the kernel pages this
+	 * way because it's always present, even when userspace is running.
+	 *
+	 * Lguest breaks this: unbeknownst to the rest of the Host kernel, we
+	 * switch to the Guest kernel.  If you don't disable this on all CPUs,
+	 * you'll get really weird bugs that you'll chase for two days.
+	 *
+	 * I used to turn PGE off every time we switched to the Guest and back
+	 * on when we return, but that slowed the Switcher down noticibly. */
+
+	/* We don't need the complexity of CPUs coming and going while we're
+	 * doing this. */
+	lock_cpu_hotplug();
+	if (cpu_has_pge) { /* We have a broader idea of "global". */
+		/* Remember that this was originally set (for cleanup). */
+		cpu_had_pge = 1;
+		/* adjust_pge is a helper function which sets or unsets the PGE
+		 * bit on its CPU, depending on the argument (0 == unset). */
+		on_each_cpu(adjust_pge, (void *)0, 0, 1);
+		/* Turn off the feature in the global feature set. */
+		clear_bit(X86_FEATURE_PGE, boot_cpu_data.x86_capability);
+	}
+	unlock_cpu_hotplug();
+};
+/*:*/
+
+void __exit lguest_arch_host_fini(void)
+{
+	/* If we had PGE before we started, turn it back on now. */
+	lock_cpu_hotplug();
+	if (cpu_had_pge) {
+		set_bit(X86_FEATURE_PGE, boot_cpu_data.x86_capability);
+		/* adjust_pge's argument "1" means set PGE. */
+		on_each_cpu(adjust_pge, (void *)1, 0, 1);
+	}
+	unlock_cpu_hotplug();
+}
+
+
+/*H:122 The i386-specific hypercalls simply farm out to the right functions. */
+int lguest_arch_do_hcall(struct lguest *lg, struct hcall_args *args)
+{
+	switch (args->arg0) {
+	case LHCALL_LOAD_GDT:
+		load_guest_gdt(lg, args->arg1, args->arg2);
+		break;
+	case LHCALL_LOAD_IDT_ENTRY:
+		load_guest_idt_entry(lg, args->arg1, args->arg2, args->arg3);
+		break;
+	case LHCALL_LOAD_TLS:
+		guest_load_tls(lg, args->arg1);
+		break;
+	default:
+		/* Bad Guest.  Bad! */
+		return -EIO;
+	}
+	return 0;
+}
+
+/*H:126 i386-specific hypercall initialization: */
+int lguest_arch_init_hypercalls(struct lguest *lg)
+{
+	u32 tsc_speed;
+
+	/* The pointer to the Guest's "struct lguest_data" is the only
+	 * argument.  We check that address now. */
+	if (!lguest_address_ok(lg, lg->hcall->arg1, sizeof(*lg->lguest_data)))
+		return -EFAULT;
+
+	/* Having checked it, we simply set lg->lguest_data to point straight
+	 * into the Launcher's memory at the right place and then use
+	 * copy_to_user/from_user from now on, instead of lgread/write.  I put
+	 * this in to show that I'm not immune to writing stupid
+	 * optimizations. */
+	lg->lguest_data = lg->mem_base + lg->hcall->arg1;
+
+	/* We insist that the Time Stamp Counter exist and doesn't change with
+	 * cpu frequency.  Some devious chip manufacturers decided that TSC
+	 * changes could be handled in software.  I decided that time going
+	 * backwards might be good for benchmarks, but it's bad for users.
+	 *
+	 * We also insist that the TSC be stable: the kernel detects unreliable
+	 * TSCs for its own purposes, and we use that here. */
+	if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && !check_tsc_unstable())
+		tsc_speed = tsc_khz;
+	else
+		tsc_speed = 0;
+	if (put_user(tsc_speed, &lg->lguest_data->tsc_khz))
+		return -EFAULT;
+
+	/* The interrupt code might not like the system call vector. */
+	if (!check_syscall_vector(lg))
+		kill_guest(lg, "bad syscall vector");
+
+	return 0;
+}
+/* Now we've examined the hypercall code; our Guest can make requests.  There
+ * is one other way we can do things for the Guest, as we see in
+ * emulate_insn(). :*/
+
+/*L:030 lguest_arch_setup_regs()
+ *
+ * Most of the Guest's registers are left alone: we used get_zeroed_page() to
+ * allocate the structure, so they will be 0. */
+void lguest_arch_setup_regs(struct lguest *lg, unsigned long start)
+{
+	struct lguest_regs *regs = lg->regs;
+
+	/* There are four "segment" registers which the Guest needs to boot:
+	 * The "code segment" register (cs) refers to the kernel code segment
+	 * __KERNEL_CS, and the "data", "extra" and "stack" segment registers
+	 * refer to the kernel data segment __KERNEL_DS.
+	 *
+	 * The privilege level is packed into the lower bits.  The Guest runs
+	 * at privilege level 1 (GUEST_PL).*/
+	regs->ds = regs->es = regs->ss = __KERNEL_DS|GUEST_PL;
+	regs->cs = __KERNEL_CS|GUEST_PL;
+
+	/* The "eflags" register contains miscellaneous flags.  Bit 1 (0x002)
+	 * is supposed to always be "1".  Bit 9 (0x200) controls whether
+	 * interrupts are enabled.  We always leave interrupts enabled while
+	 * running the Guest. */
+	regs->eflags = 0x202;
+
+	/* The "Extended Instruction Pointer" register says where the Guest is
+	 * running. */
+	regs->eip = start;
+
+	/* %esi points to our boot information, at physical address 0, so don't
+	 * touch it. */
+	/* There are a couple of GDT entries the Guest expects when first
+	 * booting. */
+
+	setup_guest_gdt(lg);
+}
diff --git a/drivers/lguest/switcher.S b/drivers/lguest/x86/switcher_32.S
index 7c9c230..1010b90 100644
--- a/drivers/lguest/switcher.S
+++ b/drivers/lguest/x86/switcher_32.S
@@ -48,7 +48,8 @@
 #include <linux/linkage.h>
 #include <asm/asm-offsets.h>
 #include <asm/page.h>
-#include "lg.h"
+#include <asm/segment.h>
+#include <asm/lguest.h>
 
 // We mark the start of the code to copy
 // It's placed in .text tho it's never run here
@@ -132,6 +133,7 @@ ENTRY(switch_to_guest)
 	// The Guest's register page has been mapped
 	// Writable onto our %esp (stack) --
 	// We can simply pop off all Guest regs.
+	popl	%eax
 	popl	%ebx
 	popl	%ecx
 	popl	%edx
@@ -139,7 +141,6 @@ ENTRY(switch_to_guest)
 	popl	%edi
 	popl	%ebp
 	popl	%gs
-	popl	%eax
 	popl	%fs
 	popl	%ds
 	popl	%es
@@ -167,7 +168,6 @@ ENTRY(switch_to_guest)
 	pushl	%es;							\
 	pushl	%ds;							\
 	pushl	%fs;							\
-	pushl	%eax;							\
 	pushl	%gs;							\
 	pushl	%ebp;							\
 	pushl	%edi;							\
@@ -175,6 +175,7 @@ ENTRY(switch_to_guest)
 	pushl	%edx;							\
 	pushl	%ecx;							\
 	pushl	%ebx;							\
+	pushl	%eax;							\
 	/* Our stack and our code are using segments			\
 	 * Set in the TSS and IDT					\
 	 * Yet if we were to touch data we'd use			\
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index ce34b53..2538816 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -3100,4 +3100,10 @@ config NETPOLL_TRAP
 config NET_POLL_CONTROLLER
 	def_bool NETPOLL
 
+config VIRTIO_NET
+	tristate "Virtio network driver (EXPERIMENTAL)"
+	depends on EXPERIMENTAL && VIRTIO
+	---help---
+	  This is the virtual network driver for lguest.  Say Y or M.
+
 endif # NETDEVICES
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 22f78cb..5932620 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -183,7 +183,6 @@ obj-$(CONFIG_ZORRO8390) += zorro8390.o
 obj-$(CONFIG_HPLANCE) += hplance.o 7990.o
 obj-$(CONFIG_MVME147_NET) += mvme147.o 7990.o
 obj-$(CONFIG_EQUALIZER) += eql.o
-obj-$(CONFIG_LGUEST_NET) += lguest_net.o
 obj-$(CONFIG_MIPS_JAZZ_SONIC) += jazzsonic.o
 obj-$(CONFIG_MIPS_AU1X00_ENET) += au1000_eth.o
 obj-$(CONFIG_MIPS_SIM_NET) += mipsnet.o
@@ -243,3 +242,4 @@ obj-$(CONFIG_FS_ENET) += fs_enet/
 
 obj-$(CONFIG_NETXEN_NIC) += netxen/
 obj-$(CONFIG_NIU) += niu.o
+obj-$(CONFIG_VIRTIO_NET) += virtio_net.o
diff --git a/drivers/net/lguest_net.c b/drivers/net/lguest_net.c
deleted file mode 100644
index abce2ee..0000000
--- a/drivers/net/lguest_net.c
+++ /dev/null
@@ -1,555 +0,0 @@
-/*D:500
- * The Guest network driver.
- *
- * This is very simple a virtual network driver, and our last Guest driver.
- * The only trick is that it can talk directly to multiple other recipients
- * (ie. other Guests on the same network).  It can also be used with only the
- * Host on the network.
- :*/
-
-/* Copyright 2006 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- */
-//#define DEBUG
-#include <linux/netdevice.h>
-#include <linux/etherdevice.h>
-#include <linux/module.h>
-#include <linux/mm_types.h>
-#include <linux/io.h>
-#include <linux/lguest_bus.h>
-
-#define SHARED_SIZE		PAGE_SIZE
-#define MAX_LANS		4
-#define NUM_SKBS		8
-
-/*M:011 Network code master Jeff Garzik points out numerous shortcomings in
- * this driver if it aspires to greatness.
- *
- * Firstly, it doesn't use "NAPI": the networking's New API, and is poorer for
- * it.  As he says "NAPI means system-wide load leveling, across multiple
- * network interfaces.  Lack of NAPI can mean competition at higher loads."
- *
- * He also points out that we don't implement set_mac_address, so users cannot
- * change the devices hardware address.  When I asked why one would want to:
- * "Bonding, and situations where you /do/ want the MAC address to "leak" out
- * of the host onto the wider net."
- *
- * Finally, he would like module unloading: "It is not unrealistic to think of
- * [un|re|]loading the net support module in an lguest guest.  And, adding
- * module support makes the programmer more responsible, because they now have
- * to learn to clean up after themselves.  Any driver that cannot clean up
- * after itself is an incomplete driver in my book."
- :*/
-
-/*D:530 The "struct lguestnet_info" contains all the information we need to
- * know about the network device. */
-struct lguestnet_info
-{
-	/* The mapped device page(s) (an array of "struct lguest_net"). */
-	struct lguest_net *peer;
-	/* The physical address of the device page(s) */
-	unsigned long peer_phys;
-	/* The size of the device page(s). */
-	unsigned long mapsize;
-
-	/* The lguest_device I come from */
-	struct lguest_device *lgdev;
-
-	/* My peerid (ie. my slot in the array). */
-	unsigned int me;
-
-	/* Receive queue: the network packets waiting to be filled. */
-	struct sk_buff *skb[NUM_SKBS];
-	struct lguest_dma dma[NUM_SKBS];
-};
-/*:*/
-
-/* How many bytes left in this page. */
-static unsigned int rest_of_page(void *data)
-{
-	return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE);
-}
-
-/*D:570 Each peer (ie. Guest or Host) on the network binds their receive
- * buffers to a different key: we simply use the physical address of the
- * device's memory page plus the peer number.  The Host insists that all keys
- * be a multiple of 4, so we multiply the peer number by 4. */
-static unsigned long peer_key(struct lguestnet_info *info, unsigned peernum)
-{
-	return info->peer_phys + 4 * peernum;
-}
-
-/* This is the routine which sets up a "struct lguest_dma" to point to a
- * network packet, similar to req_to_dma() in lguest_blk.c.  The structure of a
- * "struct sk_buff" has grown complex over the years: it consists of a "head"
- * linear section pointed to by "skb->data", and possibly an array of
- * "fragments" in the case of a non-linear packet.
- *
- * Our receive buffers don't use fragments at all but outgoing skbs might, so
- * we handle it. */
-static void skb_to_dma(const struct sk_buff *skb, unsigned int headlen,
-		       struct lguest_dma *dma)
-{
-	unsigned int i, seg;
-
-	/* First, we put the linear region into the "struct lguest_dma".  Each
-	 * entry can't go over a page boundary, so even though all our packets
-	 * are 1514 bytes or less, we might need to use two entries here: */
-	for (i = seg = 0; i < headlen; seg++, i += rest_of_page(skb->data+i)) {
-		dma->addr[seg] = virt_to_phys(skb->data + i);
-		dma->len[seg] = min((unsigned)(headlen - i),
-				    rest_of_page(skb->data + i));
-	}
-
-	/* Now we handle the fragments: at least they're guaranteed not to go
-	 * over a page.  skb_shinfo(skb) returns a pointer to the structure
-	 * which tells us about the number of fragments and the fragment
-	 * array. */
-	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++, seg++) {
-		const skb_frag_t *f = &skb_shinfo(skb)->frags[i];
-		/* Should not happen with MTU less than 64k - 2 * PAGE_SIZE. */
-		if (seg == LGUEST_MAX_DMA_SECTIONS) {
-			/* We will end up sending a truncated packet should
-			 * this ever happen.  Plus, a cool log message! */
-			printk("Woah dude!  Megapacket!\n");
-			break;
-		}
-		dma->addr[seg] = page_to_phys(f->page) + f->page_offset;
-		dma->len[seg] = f->size;
-	}
-
-	/* If after all that we didn't use the entire "struct lguest_dma"
-	 * array, we terminate it with a 0 length. */
-	if (seg < LGUEST_MAX_DMA_SECTIONS)
-		dma->len[seg] = 0;
-}
-
-/*
- * Packet transmission.
- *
- * Our packet transmission is a little unusual.  A real network card would just
- * send out the packet and leave the receivers to decide if they're interested.
- * Instead, we look through the network device memory page and see if any of
- * the ethernet addresses match the packet destination, and if so we send it to
- * that Guest.
- *
- * This is made a little more complicated in two cases.  The first case is
- * broadcast packets: for that we send the packet to all Guests on the network,
- * one at a time.  The second case is "promiscuous" mode, where a Guest wants
- * to see all the packets on the network.  We need a way for the Guest to tell
- * us it wants to see all packets, so it sets the "multicast" bit on its
- * published MAC address, which is never valid in a real ethernet address.
- */
-#define PROMISC_BIT		0x01
-
-/* This is the callback which is summoned whenever the network device's
- * multicast or promiscuous state changes.  If the card is in promiscuous mode,
- * we advertise that in our ethernet address in the device's memory.  We do the
- * same if Linux wants any or all multicast traffic.  */
-static void lguestnet_set_multicast(struct net_device *dev)
-{
-	struct lguestnet_info *info = netdev_priv(dev);
-
-	if ((dev->flags & (IFF_PROMISC|IFF_ALLMULTI)) || dev->mc_count)
-		info->peer[info->me].mac[0] |= PROMISC_BIT;
-	else
-		info->peer[info->me].mac[0] &= ~PROMISC_BIT;
-}
-
-/* A simple test function to see if a peer wants to see all packets.*/
-static int promisc(struct lguestnet_info *info, unsigned int peer)
-{
-	return info->peer[peer].mac[0] & PROMISC_BIT;
-}
-
-/* Another simple function to see if a peer's advertised ethernet address
- * matches a packet's destination ethernet address. */
-static int mac_eq(const unsigned char mac[ETH_ALEN],
-		  struct lguestnet_info *info, unsigned int peer)
-{
-	/* Ignore multicast bit, which peer turns on to mean promisc. */
-	if ((info->peer[peer].mac[0] & (~PROMISC_BIT)) != mac[0])
-		return 0;
-	return memcmp(mac+1, info->peer[peer].mac+1, ETH_ALEN-1) == 0;
-}
-
-/* This is the function which actually sends a packet once we've decided a
- * peer wants it: */
-static void transfer_packet(struct net_device *dev,
-			    struct sk_buff *skb,
-			    unsigned int peernum)
-{
-	struct lguestnet_info *info = netdev_priv(dev);
-	struct lguest_dma dma;
-
-	/* We use our handy "struct lguest_dma" packing function to prepare
-	 * the skb for sending. */
-	skb_to_dma(skb, skb_headlen(skb), &dma);
-	pr_debug("xfer length %04x (%u)\n", htons(skb->len), skb->len);
-
-	/* This is the actual send call which copies the packet. */
-	lguest_send_dma(peer_key(info, peernum), &dma);
-
-	/* Check that the entire packet was transmitted.  If not, it could mean
-	 * that the other Guest registered a short receive buffer, but this
-	 * driver should never do that.  More likely, the peer is dead. */
-	if (dma.used_len != skb->len) {
-		dev->stats.tx_carrier_errors++;
-		pr_debug("Bad xfer to peer %i: %i of %i (dma %p/%i)\n",
-			 peernum, dma.used_len, skb->len,
-			 (void *)dma.addr[0], dma.len[0]);
-	} else {
-		/* On success we update the stats. */
-		dev->stats.tx_bytes += skb->len;
-		dev->stats.tx_packets++;
-	}
-}
-
-/* Another helper function to tell is if a slot in the device memory is unused.
- * Since we always set the Local Assignment bit in the ethernet address, the
- * first byte can never be 0. */
-static int unused_peer(const struct lguest_net peer[], unsigned int num)
-{
-	return peer[num].mac[0] == 0;
-}
-
-/* Finally, here is the routine which handles an outgoing packet.  It's called
- * "start_xmit" for traditional reasons. */
-static int lguestnet_start_xmit(struct sk_buff *skb, struct net_device *dev)
-{
-	unsigned int i;
-	int broadcast;
-	struct lguestnet_info *info = netdev_priv(dev);
-	/* Extract the destination ethernet address from the packet. */
-	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
-	DECLARE_MAC_BUF(mac);
-
-	pr_debug("%s: xmit %s\n", dev->name, print_mac(mac, dest));
-
-	/* If it's a multicast packet, we broadcast to everyone.  That's not
-	 * very efficient, but there are very few applications which actually
-	 * use multicast, which is a shame really.
-	 *
-	 * As etherdevice.h points out: "By definition the broadcast address is
-	 * also a multicast address."  So we don't have to test for broadcast
-	 * packets separately. */
-	broadcast = is_multicast_ether_addr(dest);
-
-	/* Look through all the published ethernet addresses to see if we
-	 * should send this packet. */
-	for (i = 0; i < info->mapsize/sizeof(struct lguest_net); i++) {
-		/* We don't send to ourselves (we actually can't SEND_DMA to
-		 * ourselves anyway), and don't send to unused slots.*/
-		if (i == info->me || unused_peer(info->peer, i))
-			continue;
-
-		/* If it's broadcast we send it.  If they want every packet we
-		 * send it.  If the destination matches their address we send
-		 * it.  Otherwise we go to the next peer. */
-		if (!broadcast && !promisc(info, i) && !mac_eq(dest, info, i))
-			continue;
-
-		pr_debug("lguestnet %s: sending from %i to %i\n",
-			 dev->name, info->me, i);
-		/* Our routine which actually does the transfer. */
-		transfer_packet(dev, skb, i);
-	}
-
-	/* An xmit routine is expected to dispose of the packet, so we do. */
-	dev_kfree_skb(skb);
-
-	/* As per kernel convention, 0 means success.  This is why I love
-	 * networking: even if we never sent to anyone, that's still
-	 * success! */
-	return 0;
-}
-
-/*D:560
- * Packet receiving.
- *
- * First, here's a helper routine which fills one of our array of receive
- * buffers: */
-static int fill_slot(struct net_device *dev, unsigned int slot)
-{
-	struct lguestnet_info *info = netdev_priv(dev);
-
-	/* We can receive ETH_DATA_LEN (1500) byte packets, plus a standard
-	 * ethernet header of ETH_HLEN (14) bytes. */
-	info->skb[slot] = netdev_alloc_skb(dev, ETH_HLEN + ETH_DATA_LEN);
-	if (!info->skb[slot]) {
-		printk("%s: could not fill slot %i\n", dev->name, slot);
-		return -ENOMEM;
-	}
-
-	/* skb_to_dma() is a helper which sets up the "struct lguest_dma" to
-	 * point to the data in the skb: we also use it for sending out a
-	 * packet. */
-	skb_to_dma(info->skb[slot], ETH_HLEN + ETH_DATA_LEN, &info->dma[slot]);
-
-	/* This is a Write Memory Barrier: it ensures that the entry in the
-	 * receive buffer array is written *before* we set the "used_len" entry
-	 * to 0.  If the Host were looking at the receive buffer array from a
-	 * different CPU, it could potentially see "used_len = 0" and not see
-	 * the updated receive buffer information.  This would be a horribly
-	 * nasty bug, so make sure the compiler and CPU know this has to happen
-	 * first. */
-	wmb();
-	/* Writing 0 to "used_len" tells the Host it can use this receive
-	 * buffer now. */
-	info->dma[slot].used_len = 0;
-	return 0;
-}
-
-/* This is the actual receive routine.  When we receive an interrupt from the
- * Host to tell us a packet has been delivered, we arrive here: */
-static irqreturn_t lguestnet_rcv(int irq, void *dev_id)
-{
-	struct net_device *dev = dev_id;
-	struct lguestnet_info *info = netdev_priv(dev);
-	unsigned int i, done = 0;
-
-	/* Look through our entire receive array for an entry which has data
-	 * in it. */
-	for (i = 0; i < ARRAY_SIZE(info->dma); i++) {
-		unsigned int length;
-		struct sk_buff *skb;
-
-		length = info->dma[i].used_len;
-		if (length == 0)
-			continue;
-
-		/* We've found one!  Remember the skb (we grabbed the length
-		 * above), and immediately refill the slot we've taken it
-		 * from. */
-		done++;
-		skb = info->skb[i];
-		fill_slot(dev, i);
-
-		/* This shouldn't happen: micropackets could be sent by a
-		 * badly-behaved Guest on the network, but the Host will never
-		 * stuff more data in the buffer than the buffer length. */
-		if (length < ETH_HLEN || length > ETH_HLEN + ETH_DATA_LEN) {
-			pr_debug(KERN_WARNING "%s: unbelievable skb len: %i\n",
-				 dev->name, length);
-			dev_kfree_skb(skb);
-			continue;
-		}
-
-		/* skb_put(), what a great function!  I've ranted about this
-		 * function before (http://lkml.org/lkml/1999/9/26/24).  You
-		 * call it after you've added data to the end of an skb (in
-		 * this case, it was the Host which wrote the data). */
-		skb_put(skb, length);
-
-		/* The ethernet header contains a protocol field: we use the
-		 * standard helper to extract it, and place the result in
-		 * skb->protocol.  The helper also sets up skb->pkt_type and
-		 * eats up the ethernet header from the front of the packet. */
-		skb->protocol = eth_type_trans(skb, dev);
-
-		/* If this device doesn't need checksums for sending, we also
-		 * don't need to check the packets when they come in. */
-		if (dev->features & NETIF_F_NO_CSUM)
-			skb->ip_summed = CHECKSUM_UNNECESSARY;
-
-		/* As a last resort for debugging the driver or the lguest I/O
-		 * subsystem, you can uncomment the "#define DEBUG" at the top
-		 * of this file, which turns all the pr_debug() into printk()
-		 * and floods the logs. */
-		pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
-			 ntohs(skb->protocol), skb->len, skb->pkt_type);
-
-		/* Update the packet and byte counts (visible from ifconfig,
-		 * and good for debugging). */
-		dev->stats.rx_bytes += skb->len;
-		dev->stats.rx_packets++;
-
-		/* Hand our fresh network packet into the stack's "network
-		 * interface receive" routine.  That will free the packet
-		 * itself when it's finished. */
-		netif_rx(skb);
-	}
-
-	/* If we found any packets, we assume the interrupt was for us. */
-	return done ? IRQ_HANDLED : IRQ_NONE;
-}
-
-/*D:550 This is where we start: when the device is brought up by dhcpd or
- * ifconfig.  At this point we advertise our MAC address to the rest of the
- * network, and register receive buffers ready for incoming packets. */
-static int lguestnet_open(struct net_device *dev)
-{
-	int i;
-	struct lguestnet_info *info = netdev_priv(dev);
-
-	/* Copy our MAC address into the device page, so others on the network
-	 * can find us. */
-	memcpy(info->peer[info->me].mac, dev->dev_addr, ETH_ALEN);
-
-	/* We might already be in promisc mode (dev->flags & IFF_PROMISC).  Our
-	 * set_multicast callback handles this already, so we call it now. */
-	lguestnet_set_multicast(dev);
-
-	/* Allocate packets and put them into our "struct lguest_dma" array.
-	 * If we fail to allocate all the packets we could still limp along,
-	 * but it's a sign of real stress so we should probably give up now. */
-	for (i = 0; i < ARRAY_SIZE(info->dma); i++) {
-		if (fill_slot(dev, i) != 0)
-			goto cleanup;
-	}
-
-	/* Finally we tell the Host where our array of "struct lguest_dma"
-	 * receive buffers is, binding it to the key corresponding to the
-	 * device's physical memory plus our peerid. */
-	if (lguest_bind_dma(peer_key(info,info->me), info->dma,
-			    NUM_SKBS, lgdev_irq(info->lgdev)) != 0)
-		goto cleanup;
-	return 0;
-
-cleanup:
-	while (--i >= 0)
-		dev_kfree_skb(info->skb[i]);
-	return -ENOMEM;
-}
-/*:*/
-
-/* The close routine is called when the device is no longer in use: we clean up
- * elegantly. */
-static int lguestnet_close(struct net_device *dev)
-{
-	unsigned int i;
-	struct lguestnet_info *info = netdev_priv(dev);
-
-	/* Clear all trace of our existence out of the device memory by setting
-	 * the slot which held our MAC address to 0 (unused). */
-	memset(&info->peer[info->me], 0, sizeof(info->peer[info->me]));
-
-	/* Unregister our array of receive buffers */
-	lguest_unbind_dma(peer_key(info, info->me), info->dma);
-	for (i = 0; i < ARRAY_SIZE(info->dma); i++)
-		dev_kfree_skb(info->skb[i]);
-	return 0;
-}
-
-/*D:510 The network device probe function is basically a standard ethernet
- * device setup.  It reads the "struct lguest_device_desc" and sets the "struct
- * net_device".  Oh, the line-by-line excitement!  Let's skip over it. :*/
-static int lguestnet_probe(struct lguest_device *lgdev)
-{
-	int err, irqf = IRQF_SHARED;
-	struct net_device *dev;
-	struct lguestnet_info *info;
-	struct lguest_device_desc *desc = &lguest_devices[lgdev->index];
-
-	pr_debug("lguest_net: probing for device %i\n", lgdev->index);
-
-	dev = alloc_etherdev(sizeof(struct lguestnet_info));
-	if (!dev)
-		return -ENOMEM;
-
-	/* Ethernet defaults with some changes */
-	ether_setup(dev);
-	dev->set_mac_address = NULL;
-
-	dev->dev_addr[0] = 0x02; /* set local assignment bit (IEEE802) */
-	dev->dev_addr[1] = 0x00;
-	memcpy(&dev->dev_addr[2], &lguest_data.guestid, 2);
-	dev->dev_addr[4] = 0x00;
-	dev->dev_addr[5] = 0x00;
-
-	dev->open = lguestnet_open;
-	dev->stop = lguestnet_close;
-	dev->hard_start_xmit = lguestnet_start_xmit;
-
-	/* We don't actually support multicast yet, but turning on/off
-	 * promisc also calls dev->set_multicast_list. */
-	dev->set_multicast_list = lguestnet_set_multicast;
-	SET_NETDEV_DEV(dev, &lgdev->dev);
-
-	/* The network code complains if you have "scatter-gather" capability
-	 * if you don't also handle checksums (it seem that would be
-	 * "illogical").  So we use a lie of omission and don't tell it that we
-	 * can handle scattered packets unless we also don't want checksums,
-	 * even though to us they're completely independent. */
-	if (desc->features & LGUEST_NET_F_NOCSUM)
-		dev->features = NETIF_F_SG|NETIF_F_NO_CSUM;
-
-	info = netdev_priv(dev);
-	info->mapsize = PAGE_SIZE * desc->num_pages;
-	info->peer_phys = ((unsigned long)desc->pfn << PAGE_SHIFT);
-	info->lgdev = lgdev;
-	info->peer = lguest_map(info->peer_phys, desc->num_pages);
-	if (!info->peer) {
-		err = -ENOMEM;
-		goto free;
-	}
-
-	/* This stores our peerid (upper bits reserved for future). */
-	info->me = (desc->features & (info->mapsize-1));
-
-	err = register_netdev(dev);
-	if (err) {
-		pr_debug("lguestnet: registering device failed\n");
-		goto unmap;
-	}
-
-	if (lguest_devices[lgdev->index].features & LGUEST_DEVICE_F_RANDOMNESS)
-		irqf |= IRQF_SAMPLE_RANDOM;
-	if (request_irq(lgdev_irq(lgdev), lguestnet_rcv, irqf, "lguestnet",
-			dev) != 0) {
-		pr_debug("lguestnet: cannot get irq %i\n", lgdev_irq(lgdev));
-		goto unregister;
-	}
-
-	pr_debug("lguestnet: registered device %s\n", dev->name);
-	/* Finally, we put the "struct net_device" in the generic "struct
-	 * lguest_device"s private pointer.  Again, it's not necessary, but
-	 * makes sure the cool kernel kids don't tease us. */
-	lgdev->private = dev;
-	return 0;
-
-unregister:
-	unregister_netdev(dev);
-unmap:
-	lguest_unmap(info->peer);
-free:
-	free_netdev(dev);
-	return err;
-}
-
-static struct lguest_driver lguestnet_drv = {
-	.name = "lguestnet",
-	.owner = THIS_MODULE,
-	.device_type = LGUEST_DEVICE_T_NET,
-	.probe = lguestnet_probe,
-};
-
-static __init int lguestnet_init(void)
-{
-	return register_lguest_driver(&lguestnet_drv);
-}
-module_init(lguestnet_init);
-
-MODULE_DESCRIPTION("Lguest network driver");
-MODULE_LICENSE("GPL");
-
-/*D:580
- * This is the last of the Drivers, and with this we have covered the many and
- * wonderous and fine (and boring) details of the Guest.
- *
- * "make Launcher" beckons, where we answer questions like "Where do Guests
- * come from?", and "What do you do when someone asks for optimization?"
- */
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
new file mode 100644
index 0000000..e396c9d
--- /dev/null
+++ b/drivers/net/virtio_net.c
@@ -0,0 +1,435 @@
+/* A simple network driver using virtio.
+ *
+ * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+//#define DEBUG
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/module.h>
+#include <linux/virtio.h>
+#include <linux/virtio_net.h>
+#include <linux/scatterlist.h>
+
+/* FIXME: MTU in config. */
+#define MAX_PACKET_LEN (ETH_HLEN+ETH_DATA_LEN)
+
+struct virtnet_info
+{
+	struct virtio_device *vdev;
+	struct virtqueue *rvq, *svq;
+	struct net_device *dev;
+	struct napi_struct napi;
+
+	/* Number of input buffers, and max we've ever had. */
+	unsigned int num, max;
+
+	/* Receive & send queues. */
+	struct sk_buff_head recv;
+	struct sk_buff_head send;
+};
+
+static inline struct virtio_net_hdr *skb_vnet_hdr(struct sk_buff *skb)
+{
+	return (struct virtio_net_hdr *)skb->cb;
+}
+
+static inline void vnet_hdr_to_sg(struct scatterlist *sg, struct sk_buff *skb)
+{
+	sg_init_one(sg, skb_vnet_hdr(skb), sizeof(struct virtio_net_hdr));
+}
+
+static bool skb_xmit_done(struct virtqueue *rvq)
+{
+	struct virtnet_info *vi = rvq->vdev->priv;
+
+	/* In case we were waiting for output buffers. */
+	netif_wake_queue(vi->dev);
+	return true;
+}
+
+static void receive_skb(struct net_device *dev, struct sk_buff *skb,
+			unsigned len)
+{
+	struct virtio_net_hdr *hdr = skb_vnet_hdr(skb);
+
+	if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) {
+		pr_debug("%s: short packet %i\n", dev->name, len);
+		dev->stats.rx_length_errors++;
+		goto drop;
+	}
+	len -= sizeof(struct virtio_net_hdr);
+	BUG_ON(len > MAX_PACKET_LEN);
+
+	skb_trim(skb, len);
+	skb->protocol = eth_type_trans(skb, dev);
+	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
+		 ntohs(skb->protocol), skb->len, skb->pkt_type);
+	dev->stats.rx_bytes += skb->len;
+	dev->stats.rx_packets++;
+
+	if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+		pr_debug("Needs csum!\n");
+		skb->ip_summed = CHECKSUM_PARTIAL;
+		skb->csum_start = hdr->csum_start;
+		skb->csum_offset = hdr->csum_offset;
+		if (skb->csum_start > skb->len - 2
+		    || skb->csum_offset > skb->len - 2) {
+			if (net_ratelimit())
+				printk(KERN_WARNING "%s: csum=%u/%u len=%u\n",
+				       dev->name, skb->csum_start,
+				       skb->csum_offset, skb->len);
+			goto frame_err;
+		}
+	}
+
+	if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+		pr_debug("GSO!\n");
+		switch (hdr->gso_type) {
+		case VIRTIO_NET_HDR_GSO_TCPV4:
+			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
+			break;
+		case VIRTIO_NET_HDR_GSO_TCPV4_ECN:
+			skb_shinfo(skb)->gso_type = SKB_GSO_TCP_ECN;
+			break;
+		case VIRTIO_NET_HDR_GSO_UDP:
+			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
+			break;
+		case VIRTIO_NET_HDR_GSO_TCPV6:
+			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
+			break;
+		default:
+			if (net_ratelimit())
+				printk(KERN_WARNING "%s: bad gso type %u.\n",
+				       dev->name, hdr->gso_type);
+			goto frame_err;
+		}
+
+		skb_shinfo(skb)->gso_size = hdr->gso_size;
+		if (skb_shinfo(skb)->gso_size == 0) {
+			if (net_ratelimit())
+				printk(KERN_WARNING "%s: zero gso size.\n",
+				       dev->name);
+			goto frame_err;
+		}
+
+		/* Header must be checked, and gso_segs computed. */
+		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
+		skb_shinfo(skb)->gso_segs = 0;
+	}
+
+	netif_receive_skb(skb);
+	return;
+
+frame_err:
+	dev->stats.rx_frame_errors++;
+drop:
+	dev_kfree_skb(skb);
+}
+
+static void try_fill_recv(struct virtnet_info *vi)
+{
+	struct sk_buff *skb;
+	struct scatterlist sg[1+MAX_SKB_FRAGS];
+	int num, err;
+
+	for (;;) {
+		skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN);
+		if (unlikely(!skb))
+			break;
+
+		skb_put(skb, MAX_PACKET_LEN);
+		vnet_hdr_to_sg(sg, skb);
+		num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
+		skb_queue_head(&vi->recv, skb);
+
+		err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, num, skb);
+		if (err) {
+			skb_unlink(skb, &vi->recv);
+			kfree_skb(skb);
+			break;
+		}
+		vi->num++;
+	}
+	if (unlikely(vi->num > vi->max))
+		vi->max = vi->num;
+	vi->rvq->vq_ops->kick(vi->rvq);
+}
+
+static bool skb_recv_done(struct virtqueue *rvq)
+{
+	struct virtnet_info *vi = rvq->vdev->priv;
+	netif_rx_schedule(vi->dev, &vi->napi);
+	/* Suppress further interrupts. */
+	return false;
+}
+
+static int virtnet_poll(struct napi_struct *napi, int budget)
+{
+	struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
+	struct sk_buff *skb = NULL;
+	unsigned int len, received = 0;
+
+again:
+	while (received < budget &&
+	       (skb = vi->rvq->vq_ops->get_buf(vi->rvq, &len)) != NULL) {
+		__skb_unlink(skb, &vi->recv);
+		receive_skb(vi->dev, skb, len);
+		vi->num--;
+		received++;
+	}
+
+	/* FIXME: If we oom and completely run out of inbufs, we need
+	 * to start a timer trying to fill more. */
+	if (vi->num < vi->max / 2)
+		try_fill_recv(vi);
+
+	/* All done? */
+	if (!skb) {
+		netif_rx_complete(vi->dev, napi);
+		if (unlikely(!vi->rvq->vq_ops->restart(vi->rvq))
+		    && netif_rx_reschedule(vi->dev, napi))
+			goto again;
+	}
+
+	return received;
+}
+
+static void free_old_xmit_skbs(struct virtnet_info *vi)
+{
+	struct sk_buff *skb;
+	unsigned int len;
+
+	while ((skb = vi->svq->vq_ops->get_buf(vi->svq, &len)) != NULL) {
+		pr_debug("Sent skb %p\n", skb);
+		__skb_unlink(skb, &vi->send);
+		vi->dev->stats.tx_bytes += len;
+		vi->dev->stats.tx_packets++;
+		kfree_skb(skb);
+	}
+}
+
+static int start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	int num, err;
+	struct scatterlist sg[1+MAX_SKB_FRAGS];
+	struct virtio_net_hdr *hdr;
+	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
+	DECLARE_MAC_BUF(mac);
+
+	pr_debug("%s: xmit %p %s\n", dev->name, skb, print_mac(mac, dest));
+
+	free_old_xmit_skbs(vi);
+
+	/* Encode metadata header at front. */
+	hdr = skb_vnet_hdr(skb);
+	if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+		hdr->csum_start = skb->csum_start - skb_headroom(skb);
+		hdr->csum_offset = skb->csum_offset;
+	} else {
+		hdr->flags = 0;
+		hdr->csum_offset = hdr->csum_start = 0;
+	}
+
+	if (skb_is_gso(skb)) {
+		hdr->gso_size = skb_shinfo(skb)->gso_size;
+		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
+			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4_ECN;
+		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
+			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
+			hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+		else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
+			hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
+		else
+			BUG();
+	} else {
+		hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
+		hdr->gso_size = 0;
+	}
+
+	vnet_hdr_to_sg(sg, skb);
+	num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1;
+	__skb_queue_head(&vi->send, skb);
+	err = vi->svq->vq_ops->add_buf(vi->svq, sg, num, 0, skb);
+	if (err) {
+		pr_debug("%s: virtio not prepared to send\n", dev->name);
+		skb_unlink(skb, &vi->send);
+		netif_stop_queue(dev);
+		return NETDEV_TX_BUSY;
+	}
+	vi->svq->vq_ops->kick(vi->svq);
+
+	return 0;
+}
+
+static int virtnet_open(struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+
+	try_fill_recv(vi);
+
+	/* If we didn't even get one input buffer, we're useless. */
+	if (vi->num == 0)
+		return -ENOMEM;
+
+	napi_enable(&vi->napi);
+	return 0;
+}
+
+static int virtnet_close(struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	struct sk_buff *skb;
+
+	napi_disable(&vi->napi);
+
+	/* networking core has neutered skb_xmit_done/skb_recv_done, so don't
+	 * worry about races vs. get(). */
+	vi->rvq->vq_ops->shutdown(vi->rvq);
+	while ((skb = __skb_dequeue(&vi->recv)) != NULL) {
+		kfree_skb(skb);
+		vi->num--;
+	}
+	vi->svq->vq_ops->shutdown(vi->svq);
+	while ((skb = __skb_dequeue(&vi->send)) != NULL)
+		kfree_skb(skb);
+
+	BUG_ON(vi->num != 0);
+	return 0;
+}
+
+static int virtnet_probe(struct virtio_device *vdev)
+{
+	int err;
+	unsigned int len;
+	struct net_device *dev;
+	struct virtnet_info *vi;
+	void *token;
+
+	/* Allocate ourselves a network device with room for our info */
+	dev = alloc_etherdev(sizeof(struct virtnet_info));
+	if (!dev)
+		return -ENOMEM;
+
+	/* Set up network device as normal. */
+	ether_setup(dev);
+	dev->open = virtnet_open;
+	dev->stop = virtnet_close;
+	dev->hard_start_xmit = start_xmit;
+	dev->features = NETIF_F_HIGHDMA;
+	SET_NETDEV_DEV(dev, &vdev->dev);
+
+	/* Do we support "hardware" checksums? */
+	token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_F, &len);
+	if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_NO_CSUM)) {
+		/* This opens up the world of extra features. */
+		dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
+		if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4))
+			dev->features |= NETIF_F_TSO;
+		if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_UFO))
+			dev->features |= NETIF_F_UFO;
+		if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO4_ECN))
+			dev->features |= NETIF_F_TSO_ECN;
+		if (virtio_use_bit(vdev, token, len, VIRTIO_NET_F_TSO6))
+			dev->features |= NETIF_F_TSO6;
+	}
+
+	/* Configuration may specify what MAC to use.  Otherwise random. */
+	token = vdev->config->find(vdev, VIRTIO_CONFIG_NET_MAC_F, &len);
+	if (token) {
+		dev->addr_len = len;
+		vdev->config->get(vdev, token, dev->dev_addr, len);
+	} else
+		random_ether_addr(dev->dev_addr);
+
+	/* Set up our device-specific information */
+	vi = netdev_priv(dev);
+	netif_napi_add(dev, &vi->napi, virtnet_poll, 16);
+	vi->dev = dev;
+	vi->vdev = vdev;
+
+	/* We expect two virtqueues, receive then send. */
+	vi->rvq = vdev->config->find_vq(vdev, skb_recv_done);
+	if (IS_ERR(vi->rvq)) {
+		err = PTR_ERR(vi->rvq);
+		goto free;
+	}
+
+	vi->svq = vdev->config->find_vq(vdev, skb_xmit_done);
+	if (IS_ERR(vi->svq)) {
+		err = PTR_ERR(vi->svq);
+		goto free_recv;
+	}
+
+	/* Initialize our empty receive and send queues. */
+	skb_queue_head_init(&vi->recv);
+	skb_queue_head_init(&vi->send);
+
+	err = register_netdev(dev);
+	if (err) {
+		pr_debug("virtio_net: registering device failed\n");
+		goto free_send;
+	}
+	pr_debug("virtnet: registered device %s\n", dev->name);
+	vdev->priv = vi;
+	return 0;
+
+free_send:
+	vdev->config->del_vq(vi->svq);
+free_recv:
+	vdev->config->del_vq(vi->rvq);
+free:
+	free_netdev(dev);
+	return err;
+}
+
+static void virtnet_remove(struct virtio_device *vdev)
+{
+	unregister_netdev(vdev->priv);
+	free_netdev(vdev->priv);
+}
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static struct virtio_driver virtio_net = {
+	.driver.name =	KBUILD_MODNAME,
+	.driver.owner =	THIS_MODULE,
+	.id_table =	id_table,
+	.probe =	virtnet_probe,
+	.remove =	__devexit_p(virtnet_remove),
+};
+
+static int __init init(void)
+{
+	return register_virtio_driver(&virtio_net);
+}
+
+static void __exit fini(void)
+{
+	unregister_virtio_driver(&virtio_net);
+}
+module_init(init);
+module_exit(fini);
+
+MODULE_DEVICE_TABLE(virtio, id_table);
+MODULE_DESCRIPTION("Virtio network driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
new file mode 100644
index 0000000..9e33fc4
--- /dev/null
+++ b/drivers/virtio/Kconfig
@@ -0,0 +1,8 @@
+# Virtio always gets selected by whoever wants it.
+config VIRTIO
+	bool
+
+# Similarly the virtio ring implementation.
+config VIRTIO_RING
+	bool
+	depends on VIRTIO
diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
new file mode 100644
index 0000000..f70e409
--- /dev/null
+++ b/drivers/virtio/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_VIRTIO) += virtio.o
+obj-$(CONFIG_VIRTIO_RING) += virtio_ring.o
diff --git a/drivers/virtio/config.c b/drivers/virtio/config.c
new file mode 100644
index 0000000..983d482
--- /dev/null
+++ b/drivers/virtio/config.c
@@ -0,0 +1,13 @@
+/* Configuration space parsing helpers for virtio.
+ *
+ * The configuration is [type][len][... len bytes ...] fields.
+ *
+ * Copyright 2007 Rusty Russell, IBM Corporation.
+ * GPL v2 or later.
+ */
+#include <linux/err.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/bug.h>
+#include <asm/system.h>
+
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
new file mode 100644
index 0000000..15d7787
--- /dev/null
+++ b/drivers/virtio/virtio.c
@@ -0,0 +1,189 @@
+#include <linux/virtio.h>
+#include <linux/spinlock.h>
+#include <linux/virtio_config.h>
+
+static ssize_t device_show(struct device *_d,
+			   struct device_attribute *attr, char *buf)
+{
+	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
+	return sprintf(buf, "%hu", dev->id.device);
+}
+static ssize_t vendor_show(struct device *_d,
+			   struct device_attribute *attr, char *buf)
+{
+	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
+	return sprintf(buf, "%hu", dev->id.vendor);
+}
+static ssize_t status_show(struct device *_d,
+			   struct device_attribute *attr, char *buf)
+{
+	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
+	return sprintf(buf, "0x%08x", dev->config->get_status(dev));
+}
+static ssize_t modalias_show(struct device *_d,
+			     struct device_attribute *attr, char *buf)
+{
+	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
+
+	return sprintf(buf, "virtio:d%08Xv%08X\n",
+		       dev->id.device, dev->id.vendor);
+}
+static struct device_attribute virtio_dev_attrs[] = {
+	__ATTR_RO(device),
+	__ATTR_RO(vendor),
+	__ATTR_RO(status),
+	__ATTR_RO(modalias),
+	__ATTR_NULL
+};
+
+static inline int virtio_id_match(const struct virtio_device *dev,
+				  const struct virtio_device_id *id)
+{
+	if (id->device != dev->id.device)
+		return 0;
+
+	return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor != dev->id.vendor;
+}
+
+/* This looks through all the IDs a driver claims to support.  If any of them
+ * match, we return 1 and the kernel will call virtio_dev_probe(). */
+static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
+{
+	unsigned int i;
+	struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
+	const struct virtio_device_id *ids;
+
+	ids = container_of(_dr, struct virtio_driver, driver)->id_table;
+	for (i = 0; ids[i].device; i++)
+		if (virtio_id_match(dev, &ids[i]))
+			return 1;
+	return 0;
+}
+
+static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
+{
+	struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
+
+	return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
+			      dev->id.device, dev->id.vendor);
+}
+
+static struct bus_type virtio_bus = {
+	.name  = "virtio",
+	.match = virtio_dev_match,
+	.dev_attrs = virtio_dev_attrs,
+	.uevent = virtio_uevent,
+};
+
+static void add_status(struct virtio_device *dev, unsigned status)
+{
+	dev->config->set_status(dev, dev->config->get_status(dev) | status);
+}
+
+static int virtio_dev_probe(struct device *_d)
+{
+	int err;
+	struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
+	struct virtio_driver *drv = container_of(dev->dev.driver,
+						 struct virtio_driver, driver);
+
+	add_status(dev, VIRTIO_CONFIG_S_DRIVER);
+	err = drv->probe(dev);
+	if (err)
+		add_status(dev, VIRTIO_CONFIG_S_FAILED);
+	else
+		add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
+	return err;
+}
+
+int register_virtio_driver(struct virtio_driver *driver)
+{
+	driver->driver.bus = &virtio_bus;
+	driver->driver.probe = virtio_dev_probe;
+	return driver_register(&driver->driver);
+}
+EXPORT_SYMBOL_GPL(register_virtio_driver);
+
+void unregister_virtio_driver(struct virtio_driver *driver)
+{
+	driver_unregister(&driver->driver);
+}
+EXPORT_SYMBOL_GPL(unregister_virtio_driver);
+
+int register_virtio_device(struct virtio_device *dev)
+{
+	int err;
+
+	dev->dev.bus = &virtio_bus;
+	sprintf(dev->dev.bus_id, "%u", dev->index);
+
+	/* Acknowledge that we've seen the device. */
+	add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
+
+	/* device_register() causes the bus infrastructure to look for a
+	 * matching driver. */
+	err = device_register(&dev->dev);
+	if (err)
+		add_status(dev, VIRTIO_CONFIG_S_FAILED);
+	return err;
+}
+EXPORT_SYMBOL_GPL(register_virtio_device);
+
+void unregister_virtio_device(struct virtio_device *dev)
+{
+	device_unregister(&dev->dev);
+}
+EXPORT_SYMBOL_GPL(unregister_virtio_device);
+
+int __virtio_config_val(struct virtio_device *vdev,
+			u8 type, void *val, size_t size)
+{
+	void *token;
+	unsigned int len;
+
+	token = vdev->config->find(vdev, type, &len);
+	if (!token)
+		return -ENOENT;
+
+	if (len != size)
+		return -EIO;
+
+	vdev->config->get(vdev, token, val, size);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__virtio_config_val);
+
+int virtio_use_bit(struct virtio_device *vdev,
+		   void *token, unsigned int len, unsigned int bitnum)
+{
+	unsigned long bits[16];
+
+	/* This makes it convenient to pass-through find() results. */
+	if (!token)
+		return 0;
+
+	/* bit not in range of this bitfield? */
+	if (bitnum * 8 >= len / 2)
+		return 0;
+
+	/* Giant feature bitfields are silly. */
+	BUG_ON(len > sizeof(bits));
+	vdev->config->get(vdev, token, bits, len);
+
+	if (!test_bit(bitnum, bits))
+		return 0;
+
+	/* Set acknowledge bit, and write it back. */
+	set_bit(bitnum + len * 8 / 2, bits);
+	vdev->config->set(vdev, token, bits, len);
+	return 1;
+}
+EXPORT_SYMBOL_GPL(virtio_use_bit);
+
+static int virtio_init(void)
+{
+	if (bus_register(&virtio_bus) != 0)
+		panic("virtio bus registration failed");
+	return 0;
+}
+core_initcall(virtio_init);
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
new file mode 100644
index 0000000..0e4baca
--- /dev/null
+++ b/drivers/virtio/virtio_ring.c
@@ -0,0 +1,313 @@
+/* Virtio ring implementation.
+ *
+ *  Copyright 2007 Rusty Russell IBM Corporation
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#include <linux/virtio.h>
+#include <linux/virtio_ring.h>
+#include <linux/device.h>
+
+#ifdef DEBUG
+/* For development, we want to crash whenever the ring is screwed. */
+#define BAD_RING(vq, fmt...)			\
+	do { dev_err(&vq->vq.vdev->dev, fmt); BUG(); } while(0)
+#define START_USE(vq) \
+	do { if ((vq)->in_use) panic("in_use = %i\n", (vq)->in_use); (vq)->in_use = __LINE__; mb(); } while(0)
+#define END_USE(vq) \
+	do { BUG_ON(!(vq)->in_use); (vq)->in_use = 0; mb(); } while(0)
+#else
+#define BAD_RING(vq, fmt...)			\
+	do { dev_err(&vq->vq.vdev->dev, fmt); (vq)->broken = true; } while(0)
+#define START_USE(vq)
+#define END_USE(vq)
+#endif
+
+struct vring_virtqueue
+{
+	struct virtqueue vq;
+
+	/* Actual memory layout for this queue */
+	struct vring vring;
+
+	/* Other side has made a mess, don't try any more. */
+	bool broken;
+
+	/* Number of free buffers */
+	unsigned int num_free;
+	/* Head of free buffer list. */
+	unsigned int free_head;
+	/* Number we've added since last sync. */
+	unsigned int num_added;
+
+	/* Last used index we've seen. */
+	unsigned int last_used_idx;
+
+	/* How to notify other side. FIXME: commonalize hcalls! */
+	void (*notify)(struct virtqueue *vq);
+
+#ifdef DEBUG
+	/* They're supposed to lock for us. */
+	unsigned int in_use;
+#endif
+
+	/* Tokens for callbacks. */
+	void *data[];
+};
+
+#define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq)
+
+static int vring_add_buf(struct virtqueue *_vq,
+			 struct scatterlist sg[],
+			 unsigned int out,
+			 unsigned int in,
+			 void *data)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+	unsigned int i, avail, head, uninitialized_var(prev);
+
+	BUG_ON(data == NULL);
+	BUG_ON(out + in > vq->vring.num);
+	BUG_ON(out + in == 0);
+
+	START_USE(vq);
+
+	if (vq->num_free < out + in) {
+		pr_debug("Can't add buf len %i - avail = %i\n",
+			 out + in, vq->num_free);
+		END_USE(vq);
+		return -ENOSPC;
+	}
+
+	/* We're about to use some buffers from the free list. */
+	vq->num_free -= out + in;
+
+	head = vq->free_head;
+	for (i = vq->free_head; out; i = vq->vring.desc[i].next, out--) {
+		vq->vring.desc[i].flags = VRING_DESC_F_NEXT;
+		vq->vring.desc[i].addr = (page_to_pfn(sg_page(sg))<<PAGE_SHIFT)
+			+ sg->offset;
+		vq->vring.desc[i].len = sg->length;
+		prev = i;
+		sg++;
+	}
+	for (; in; i = vq->vring.desc[i].next, in--) {
+		vq->vring.desc[i].flags = VRING_DESC_F_NEXT|VRING_DESC_F_WRITE;
+		vq->vring.desc[i].addr = (page_to_pfn(sg_page(sg))<<PAGE_SHIFT)
+			+ sg->offset;
+		vq->vring.desc[i].len = sg->length;
+		prev = i;
+		sg++;
+	}
+	/* Last one doesn't continue. */
+	vq->vring.desc[prev].flags &= ~VRING_DESC_F_NEXT;
+
+	/* Update free pointer */
+	vq->free_head = i;
+
+	/* Set token. */
+	vq->data[head] = data;
+
+	/* Put entry in available array (but don't update avail->idx until they
+	 * do sync).  FIXME: avoid modulus here? */
+	avail = (vq->vring.avail->idx + vq->num_added++) % vq->vring.num;
+	vq->vring.avail->ring[avail] = head;
+
+	pr_debug("Added buffer head %i to %p\n", head, vq);
+	END_USE(vq);
+	return 0;
+}
+
+static void vring_kick(struct virtqueue *_vq)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+	START_USE(vq);
+	/* Descriptors and available array need to be set before we expose the
+	 * new available array entries. */
+	wmb();
+
+	vq->vring.avail->idx += vq->num_added;
+	vq->num_added = 0;
+
+	/* Need to update avail index before checking if we should notify */
+	mb();
+
+	if (!(vq->vring.used->flags & VRING_USED_F_NO_NOTIFY))
+		/* Prod other side to tell it about changes. */
+		vq->notify(&vq->vq);
+
+	END_USE(vq);
+}
+
+static void detach_buf(struct vring_virtqueue *vq, unsigned int head)
+{
+	unsigned int i;
+
+	/* Clear data ptr. */
+	vq->data[head] = NULL;
+
+	/* Put back on free list: find end */
+	i = head;
+	while (vq->vring.desc[i].flags & VRING_DESC_F_NEXT) {
+		i = vq->vring.desc[i].next;
+		vq->num_free++;
+	}
+
+	vq->vring.desc[i].next = vq->free_head;
+	vq->free_head = head;
+	/* Plus final descriptor */
+	vq->num_free++;
+}
+
+/* FIXME: We need to tell other side about removal, to synchronize. */
+static void vring_shutdown(struct virtqueue *_vq)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+	unsigned int i;
+
+	for (i = 0; i < vq->vring.num; i++)
+		detach_buf(vq, i);
+}
+
+static inline bool more_used(const struct vring_virtqueue *vq)
+{
+	return vq->last_used_idx != vq->vring.used->idx;
+}
+
+static void *vring_get_buf(struct virtqueue *_vq, unsigned int *len)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+	void *ret;
+	unsigned int i;
+
+	START_USE(vq);
+
+	if (!more_used(vq)) {
+		pr_debug("No more buffers in queue\n");
+		END_USE(vq);
+		return NULL;
+	}
+
+	i = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].id;
+	*len = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].len;
+
+	if (unlikely(i >= vq->vring.num)) {
+		BAD_RING(vq, "id %u out of range\n", i);
+		return NULL;
+	}
+	if (unlikely(!vq->data[i])) {
+		BAD_RING(vq, "id %u is not a head!\n", i);
+		return NULL;
+	}
+
+	/* detach_buf clears data, so grab it now. */
+	ret = vq->data[i];
+	detach_buf(vq, i);
+	vq->last_used_idx++;
+	END_USE(vq);
+	return ret;
+}
+
+static bool vring_restart(struct virtqueue *_vq)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+
+	START_USE(vq);
+	BUG_ON(!(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT));
+
+	/* We optimistically turn back on interrupts, then check if there was
+	 * more to do. */
+	vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
+	mb();
+	if (unlikely(more_used(vq))) {
+		vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
+		END_USE(vq);
+		return false;
+	}
+
+	END_USE(vq);
+	return true;
+}
+
+irqreturn_t vring_interrupt(int irq, void *_vq)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+
+	if (!more_used(vq)) {
+		pr_debug("virtqueue interrupt with no work for %p\n", vq);
+		return IRQ_NONE;
+	}
+
+	if (unlikely(vq->broken))
+		return IRQ_HANDLED;
+
+	pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback);
+	if (vq->vq.callback && !vq->vq.callback(&vq->vq))
+		vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
+
+	return IRQ_HANDLED;
+}
+
+static struct virtqueue_ops vring_vq_ops = {
+	.add_buf = vring_add_buf,
+	.get_buf = vring_get_buf,
+	.kick = vring_kick,
+	.restart = vring_restart,
+	.shutdown = vring_shutdown,
+};
+
+struct virtqueue *vring_new_virtqueue(unsigned int num,
+				      struct virtio_device *vdev,
+				      void *pages,
+				      void (*notify)(struct virtqueue *),
+				      bool (*callback)(struct virtqueue *))
+{
+	struct vring_virtqueue *vq;
+	unsigned int i;
+
+	vq = kmalloc(sizeof(*vq) + sizeof(void *)*num, GFP_KERNEL);
+	if (!vq)
+		return NULL;
+
+	vring_init(&vq->vring, num, pages);
+	vq->vq.callback = callback;
+	vq->vq.vdev = vdev;
+	vq->vq.vq_ops = &vring_vq_ops;
+	vq->notify = notify;
+	vq->broken = false;
+	vq->last_used_idx = 0;
+	vq->num_added = 0;
+#ifdef DEBUG
+	vq->in_use = false;
+#endif
+
+	/* No callback?  Tell other side not to bother us. */
+	if (!callback)
+		vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
+
+	/* Put everything in free lists. */
+	vq->num_free = num;
+	vq->free_head = 0;
+	for (i = 0; i < num-1; i++)
+		vq->vring.desc[i].next = i+1;
+
+	return &vq->vq;
+}
+
+void vring_del_virtqueue(struct virtqueue *vq)
+{
+	kfree(to_vvq(vq));
+}
+