Merge tag 'stable/for-linus-4.1-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen features and fixes from David Vrabel:

 - use a single source list of hypercalls, generating other tables etc.
   at build time.

 - add a "Xen PV" APIC driver to support >255 VCPUs in PV guests.

 - significant performance improve to guest save/restore/migration.

 - scsiback/front save/restore support.

 - infrastructure for multi-page xenbus rings.

 - misc fixes.

* tag 'stable/for-linus-4.1-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/pci: Try harder to get PXM information for Xen
  xenbus_client: Extend interface to support multi-page ring
  xen-pciback: also support disabling of bus-mastering and memory-write-invalidate
  xen: support suspend/resume in pvscsi frontend
  xen: scsiback: add LUN of restored domain
  xen-scsiback: define a pr_fmt macro with xen-pvscsi
  xen/mce: fix up xen_late_init_mcelog() error handling
  xen/privcmd: improve performance of MMAPBATCH_V2
  xen: unify foreign GFN map/unmap for auto-xlated physmap guests
  x86/xen/apic: WARN with details.
  x86/xen: Provide a "Xen PV" APIC driver to support >255 VCPUs
  xen/pciback: Don't print scary messages when unsupported by hypervisor.
  xen: use generated hypercall symbols in arch/x86/xen/xen-head.S
  xen: use generated hypervisor symbols in arch/x86/xen/trace.c
  xen: synchronize include/xen/interface/xen.h with xen
  xen: build infrastructure for generating hypercall depending symbols
  xen: balloon: Use static attribute groups for sysfs entries
  xen: pcpu: Use static attribute groups for sysfs entry

13 files changed, 665 insertions, 235 deletions

diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 94d9680..a270004 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -270,4 +270,10 @@ config XEN_EFI
 	def_bool y
 	depends on X86_64 && EFI
 
+config XEN_AUTO_XLATE
+	def_bool y
+	depends on ARM || ARM64 || XEN_PVHVM
+	help
+	  Support for auto-translated physmap guests.
+
 endmenu
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 2ccd359..40edd1c 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -37,6 +37,7 @@ obj-$(CONFIG_XEN_ACPI_HOTPLUG_CPU)	+= xen-acpi-cpuhotplug.o
 obj-$(CONFIG_XEN_ACPI_PROCESSOR)	+= xen-acpi-processor.o
 obj-$(CONFIG_XEN_EFI)			+= efi.o
 obj-$(CONFIG_XEN_SCSI_BACKEND)		+= xen-scsiback.o
+obj-$(CONFIG_XEN_AUTO_XLATE)		+= xlate_mmu.o
 xen-evtchn-y				:= evtchn.o
 xen-gntdev-y				:= gntdev.o
 xen-gntalloc-y				:= gntalloc.o
diff --git a/drivers/xen/mcelog.c b/drivers/xen/mcelog.c
index 6ab6a79..a493c7315 100644
--- a/drivers/xen/mcelog.c
+++ b/drivers/xen/mcelog.c
@@ -393,14 +393,25 @@ static int bind_virq_for_mce(void)
 
 static int __init xen_late_init_mcelog(void)
 {
+	int ret;
+
 	/* Only DOM0 is responsible for MCE logging */
-	if (xen_initial_domain()) {
-		/* register character device /dev/mcelog for xen mcelog */
-		if (misc_register(&xen_mce_chrdev_device))
-			return -ENODEV;
-		return bind_virq_for_mce();
-	}
+	if (!xen_initial_domain())
+		return -ENODEV;
+
+	/* register character device /dev/mcelog for xen mcelog */
+	ret = misc_register(&xen_mce_chrdev_device);
+	if (ret)
+		return ret;
+
+	ret = bind_virq_for_mce();
+	if (ret)
+		goto deregister;
 
-	return -ENODEV;
+	return 0;
+
+deregister:
+	misc_deregister(&xen_mce_chrdev_device);
+	return ret;
 }
 device_initcall(xen_late_init_mcelog);
diff --git a/drivers/xen/pci.c b/drivers/xen/pci.c
index 95ee430..7494dbe 100644
--- a/drivers/xen/pci.c
+++ b/drivers/xen/pci.c
@@ -19,6 +19,7 @@
 
 #include <linux/pci.h>
 #include <linux/acpi.h>
+#include <linux/pci-acpi.h>
 #include <xen/xen.h>
 #include <xen/interface/physdev.h>
 #include <xen/interface/xen.h>
@@ -67,12 +68,22 @@ static int xen_add_device(struct device *dev)
 
 #ifdef CONFIG_ACPI
 		handle = ACPI_HANDLE(&pci_dev->dev);
-		if (!handle && pci_dev->bus->bridge)
-			handle = ACPI_HANDLE(pci_dev->bus->bridge);
 #ifdef CONFIG_PCI_IOV
 		if (!handle && pci_dev->is_virtfn)
 			handle = ACPI_HANDLE(physfn->bus->bridge);
 #endif
+		if (!handle) {
+			/*
+			 * This device was not listed in the ACPI name space at
+			 * all. Try to get acpi handle of parent pci bus.
+			 */
+			struct pci_bus *pbus;
+			for (pbus = pci_dev->bus; pbus; pbus = pbus->parent) {
+				handle = acpi_pci_get_bridge_handle(pbus);
+				if (handle)
+					break;
+			}
+		}
 		if (handle) {
 			acpi_status status;
 
diff --git a/drivers/xen/pcpu.c b/drivers/xen/pcpu.c
index 0aac403..49e88f2 100644
--- a/drivers/xen/pcpu.c
+++ b/drivers/xen/pcpu.c
@@ -132,6 +132,33 @@ static ssize_t __ref store_online(struct device *dev,
 }
 static DEVICE_ATTR(online, S_IRUGO | S_IWUSR, show_online, store_online);
 
+static struct attribute *pcpu_dev_attrs[] = {
+	&dev_attr_online.attr,
+	NULL
+};
+
+static umode_t pcpu_dev_is_visible(struct kobject *kobj,
+				   struct attribute *attr, int idx)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	/*
+	 * Xen never offline cpu0 due to several restrictions
+	 * and assumptions. This basically doesn't add a sys control
+	 * to user, one cannot attempt to offline BSP.
+	 */
+	return dev->id ? attr->mode : 0;
+}
+
+static const struct attribute_group pcpu_dev_group = {
+	.attrs = pcpu_dev_attrs,
+	.is_visible = pcpu_dev_is_visible,
+};
+
+static const struct attribute_group *pcpu_dev_groups[] = {
+	&pcpu_dev_group,
+	NULL
+};
+
 static bool xen_pcpu_online(uint32_t flags)
 {
 	return !!(flags & XEN_PCPU_FLAGS_ONLINE);
@@ -181,9 +208,6 @@ static void unregister_and_remove_pcpu(struct pcpu *pcpu)
 		return;
 
 	dev = &pcpu->dev;
-	if (dev->id)
-		device_remove_file(dev, &dev_attr_online);
-
 	/* pcpu remove would be implicitly done */
 	device_unregister(dev);
 }
@@ -200,6 +224,7 @@ static int register_pcpu(struct pcpu *pcpu)
 	dev->bus = &xen_pcpu_subsys;
 	dev->id = pcpu->cpu_id;
 	dev->release = pcpu_release;
+	dev->groups = pcpu_dev_groups;
 
 	err = device_register(dev);
 	if (err) {
@@ -207,19 +232,6 @@ static int register_pcpu(struct pcpu *pcpu)
 		return err;
 	}
 
-	/*
-	 * Xen never offline cpu0 due to several restrictions
-	 * and assumptions. This basically doesn't add a sys control
-	 * to user, one cannot attempt to offline BSP.
-	 */
-	if (dev->id) {
-		err = device_create_file(dev, &dev_attr_online);
-		if (err) {
-			device_unregister(dev);
-			return err;
-		}
-	}
-
 	return 0;
 }
 
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 59ac71c..5a29616 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -159,6 +159,40 @@ static int traverse_pages(unsigned nelem, size_t size,
 	return ret;
 }
 
+/*
+ * Similar to traverse_pages, but use each page as a "block" of
+ * data to be processed as one unit.
+ */
+static int traverse_pages_block(unsigned nelem, size_t size,
+				struct list_head *pos,
+				int (*fn)(void *data, int nr, void *state),
+				void *state)
+{
+	void *pagedata;
+	unsigned pageidx;
+	int ret = 0;
+
+	BUG_ON(size > PAGE_SIZE);
+
+	pageidx = PAGE_SIZE;
+
+	while (nelem) {
+		int nr = (PAGE_SIZE/size);
+		struct page *page;
+		if (nr > nelem)
+			nr = nelem;
+		pos = pos->next;
+		page = list_entry(pos, struct page, lru);
+		pagedata = page_address(page);
+		ret = (*fn)(pagedata, nr, state);
+		if (ret)
+			break;
+		nelem -= nr;
+	}
+
+	return ret;
+}
+
 struct mmap_mfn_state {
 	unsigned long va;
 	struct vm_area_struct *vma;
@@ -274,39 +308,25 @@ struct mmap_batch_state {
 /* auto translated dom0 note: if domU being created is PV, then mfn is
  * mfn(addr on bus). If it's auto xlated, then mfn is pfn (input to HAP).
  */
-static int mmap_batch_fn(void *data, void *state)
+static int mmap_batch_fn(void *data, int nr, void *state)
 {
 	xen_pfn_t *mfnp = data;
 	struct mmap_batch_state *st = state;
 	struct vm_area_struct *vma = st->vma;
 	struct page **pages = vma->vm_private_data;
-	struct page *cur_page = NULL;
+	struct page **cur_pages = NULL;
 	int ret;
 
 	if (xen_feature(XENFEAT_auto_translated_physmap))
-		cur_page = pages[st->index++];
+		cur_pages = &pages[st->index];
 
-	ret = xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1,
-					 st->vma->vm_page_prot, st->domain,
-					 &cur_page);
+	BUG_ON(nr < 0);
+	ret = xen_remap_domain_mfn_array(st->vma, st->va & PAGE_MASK, mfnp, nr,
+					 (int *)mfnp, st->vma->vm_page_prot,
+					 st->domain, cur_pages);
 
-	/* Store error code for second pass. */
-	if (st->version == 1) {
-		if (ret < 0) {
-			/*
-			 * V1 encodes the error codes in the 32bit top nibble of the
-			 * mfn (with its known limitations vis-a-vis 64 bit callers).
-			 */
-			*mfnp |= (ret == -ENOENT) ?
-						PRIVCMD_MMAPBATCH_PAGED_ERROR :
-						PRIVCMD_MMAPBATCH_MFN_ERROR;
-		}
-	} else { /* st->version == 2 */
-		*((int *) mfnp) = ret;
-	}
-
-	/* And see if it affects the global_error. */
-	if (ret < 0) {
+	/* Adjust the global_error? */
+	if (ret != nr) {
 		if (ret == -ENOENT)
 			st->global_error = -ENOENT;
 		else {
@@ -315,23 +335,35 @@ static int mmap_batch_fn(void *data, void *state)
 				st->global_error = 1;
 		}
 	}
-	st->va += PAGE_SIZE;
+	st->va += PAGE_SIZE * nr;
+	st->index += nr;
 
 	return 0;
 }
 
-static int mmap_return_errors(void *data, void *state)
+static int mmap_return_error(int err, struct mmap_batch_state *st)
 {
-	struct mmap_batch_state *st = state;
+	int ret;
 
 	if (st->version == 1) {
-		xen_pfn_t mfnp = *((xen_pfn_t *) data);
-		if (mfnp & PRIVCMD_MMAPBATCH_MFN_ERROR)
-			return __put_user(mfnp, st->user_mfn++);
-		else
+		if (err) {
+			xen_pfn_t mfn;
+
+			ret = get_user(mfn, st->user_mfn);
+			if (ret < 0)
+				return ret;
+			/*
+			 * V1 encodes the error codes in the 32bit top
+			 * nibble of the mfn (with its known
+			 * limitations vis-a-vis 64 bit callers).
+			 */
+			mfn |= (err == -ENOENT) ?
+				PRIVCMD_MMAPBATCH_PAGED_ERROR :
+				PRIVCMD_MMAPBATCH_MFN_ERROR;
+			return __put_user(mfn, st->user_mfn++);
+		} else
 			st->user_mfn++;
 	} else { /* st->version == 2 */
-		int err = *((int *) data);
 		if (err)
 			return __put_user(err, st->user_err++);
 		else
@@ -341,6 +373,21 @@ static int mmap_return_errors(void *data, void *state)
 	return 0;
 }
 
+static int mmap_return_errors(void *data, int nr, void *state)
+{
+	struct mmap_batch_state *st = state;
+	int *errs = data;
+	int i;
+	int ret;
+
+	for (i = 0; i < nr; i++) {
+		ret = mmap_return_error(errs[i], st);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
 /* Allocate pfns that are then mapped with gmfns from foreign domid. Update
  * the vma with the page info to use later.
  * Returns: 0 if success, otherwise -errno
@@ -472,8 +519,8 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
 	state.version       = version;
 
 	/* mmap_batch_fn guarantees ret == 0 */
-	BUG_ON(traverse_pages(m.num, sizeof(xen_pfn_t),
-			     &pagelist, mmap_batch_fn, &state));
+	BUG_ON(traverse_pages_block(m.num, sizeof(xen_pfn_t),
+				    &pagelist, mmap_batch_fn, &state));
 
 	up_write(&mm->mmap_sem);
 
@@ -481,8 +528,8 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
 		/* Write back errors in second pass. */
 		state.user_mfn = (xen_pfn_t *)m.arr;
 		state.user_err = m.err;
-		ret = traverse_pages(m.num, sizeof(xen_pfn_t),
-							 &pagelist, mmap_return_errors, &state);
+		ret = traverse_pages_block(m.num, sizeof(xen_pfn_t),
+					   &pagelist, mmap_return_errors, &state);
 	} else
 		ret = 0;
 
diff --git a/drivers/xen/xen-balloon.c b/drivers/xen/xen-balloon.c
index e555845..39e7ef8 100644
--- a/drivers/xen/xen-balloon.c
+++ b/drivers/xen/xen-balloon.c
@@ -193,13 +193,18 @@ static DEVICE_ATTR(target, S_IRUGO | S_IWUSR,
 		   show_target, store_target);
 
 
-static struct device_attribute *balloon_attrs[] = {
-	&dev_attr_target_kb,
-	&dev_attr_target,
-	&dev_attr_schedule_delay.attr,
-	&dev_attr_max_schedule_delay.attr,
-	&dev_attr_retry_count.attr,
-	&dev_attr_max_retry_count.attr
+static struct attribute *balloon_attrs[] = {
+	&dev_attr_target_kb.attr,
+	&dev_attr_target.attr,
+	&dev_attr_schedule_delay.attr.attr,
+	&dev_attr_max_schedule_delay.attr.attr,
+	&dev_attr_retry_count.attr.attr,
+	&dev_attr_max_retry_count.attr.attr,
+	NULL
+};
+
+static const struct attribute_group balloon_group = {
+	.attrs = balloon_attrs
 };
 
 static struct attribute *balloon_info_attrs[] = {
@@ -214,6 +219,12 @@ static const struct attribute_group balloon_info_group = {
 	.attrs = balloon_info_attrs
 };
 
+static const struct attribute_group *balloon_groups[] = {
+	&balloon_group,
+	&balloon_info_group,
+	NULL
+};
+
 static struct bus_type balloon_subsys = {
 	.name = BALLOON_CLASS_NAME,
 	.dev_name = BALLOON_CLASS_NAME,
@@ -221,7 +232,7 @@ static struct bus_type balloon_subsys = {
 
 static int register_balloon(struct device *dev)
 {
-	int i, error;
+	int error;
 
 	error = subsys_system_register(&balloon_subsys, NULL);
 	if (error)
@@ -229,6 +240,7 @@ static int register_balloon(struct device *dev)
 
 	dev->id = 0;
 	dev->bus = &balloon_subsys;
+	dev->groups = balloon_groups;
 
 	error = device_register(dev);
 	if (error) {
@@ -236,24 +248,7 @@ static int register_balloon(struct device *dev)
 		return error;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
-		error = device_create_file(dev, balloon_attrs[i]);
-		if (error)
-			goto fail;
-	}
-
-	error = sysfs_create_group(&dev->kobj, &balloon_info_group);
-	if (error)
-		goto fail;
-
 	return 0;
-
- fail:
-	while (--i >= 0)
-		device_remove_file(dev, balloon_attrs[i]);
-	device_unregister(dev);
-	bus_unregister(&balloon_subsys);
-	return error;
 }
 
 MODULE_LICENSE("GPL");
diff --git a/drivers/xen/xen-pciback/conf_space_header.c b/drivers/xen/xen-pciback/conf_space_header.c
index 2d73693..c2260a0 100644
--- a/drivers/xen/xen-pciback/conf_space_header.c
+++ b/drivers/xen/xen-pciback/conf_space_header.c
@@ -88,9 +88,15 @@ static int command_write(struct pci_dev *dev, int offset, u16 value, void *data)
 			printk(KERN_DEBUG DRV_NAME ": %s: set bus master\n",
 			       pci_name(dev));
 		pci_set_master(dev);
+	} else if (dev->is_busmaster && !is_master_cmd(value)) {
+		if (unlikely(verbose_request))
+			printk(KERN_DEBUG DRV_NAME ": %s: clear bus master\n",
+			       pci_name(dev));
+		pci_clear_master(dev);
 	}
 
-	if (value & PCI_COMMAND_INVALIDATE) {
+	if (!(cmd->val & PCI_COMMAND_INVALIDATE) &&
+	    (value & PCI_COMMAND_INVALIDATE)) {
 		if (unlikely(verbose_request))
 			printk(KERN_DEBUG
 			       DRV_NAME ": %s: enable memory-write-invalidate\n",
@@ -101,6 +107,13 @@ static int command_write(struct pci_dev *dev, int offset, u16 value, void *data)
 				pci_name(dev), err);
 			value &= ~PCI_COMMAND_INVALIDATE;
 		}
+	} else if ((cmd->val & PCI_COMMAND_INVALIDATE) &&
+		   !(value & PCI_COMMAND_INVALIDATE)) {
+		if (unlikely(verbose_request))
+			printk(KERN_DEBUG
+			       DRV_NAME ": %s: disable memory-write-invalidate\n",
+			       pci_name(dev));
+		pci_clear_mwi(dev);
 	}
 
 	cmd->val = value;
diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
index cc3cbb4..258b7c3 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -118,7 +118,7 @@ static void pcistub_device_release(struct kref *kref)
 		int err = HYPERVISOR_physdev_op(PHYSDEVOP_release_msix,
 						&ppdev);
 
-		if (err)
+		if (err && err != -ENOSYS)
 			dev_warn(&dev->dev, "MSI-X release failed (%d)\n",
 				 err);
 	}
@@ -402,7 +402,7 @@ static int pcistub_init_device(struct pci_dev *dev)
 		};
 
 		err = HYPERVISOR_physdev_op(PHYSDEVOP_prepare_msix, &ppdev);
-		if (err)
+		if (err && err != -ENOSYS)
 			dev_err(&dev->dev, "MSI-X preparation failed (%d)\n",
 				err);
 	}
diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index fe17c80..98bc345 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -113,7 +113,7 @@ static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
 		"Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
 		gnt_ref, remote_evtchn);
 
-	err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
+	err = xenbus_map_ring_valloc(pdev->xdev, &gnt_ref, 1, &vaddr);
 	if (err < 0) {
 		xenbus_dev_fatal(pdev->xdev, err,
 				"Error mapping other domain page in ours.");
diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
index 42bd55a..07ef383 100644
--- a/drivers/xen/xen-scsiback.c
+++ b/drivers/xen/xen-scsiback.c
@@ -31,6 +31,8 @@
  * IN THE SOFTWARE.
  */
 
+#define pr_fmt(fmt) "xen-pvscsi: " fmt
+
 #include <stdarg.h>
 
 #include <linux/module.h>
@@ -69,9 +71,6 @@
 #include <xen/interface/grant_table.h>
 #include <xen/interface/io/vscsiif.h>
 
-#define DPRINTK(_f, _a...)			\
-	pr_debug("(file=%s, line=%d) " _f, __FILE__ , __LINE__ , ## _a)
-
 #define VSCSI_VERSION	"v0.1"
 #define VSCSI_NAMELEN	32
 
@@ -271,7 +270,7 @@ static void scsiback_print_status(char *sense_buffer, int errors,
 {
 	struct scsiback_tpg *tpg = pending_req->v2p->tpg;
 
-	pr_err("xen-pvscsi[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
+	pr_err("[%s:%d] cmnd[0]=%02x -> st=%02x msg=%02x host=%02x drv=%02x\n",
 	       tpg->tport->tport_name, pending_req->v2p->lun,
 	       pending_req->cmnd[0], status_byte(errors), msg_byte(errors),
 	       host_byte(errors), driver_byte(errors));
@@ -427,7 +426,7 @@ static int scsiback_gnttab_data_map_batch(struct gnttab_map_grant_ref *map,
 	BUG_ON(err);
 	for (i = 0; i < cnt; i++) {
 		if (unlikely(map[i].status != GNTST_okay)) {
-			pr_err("xen-pvscsi: invalid buffer -- could not remap it\n");
+			pr_err("invalid buffer -- could not remap it\n");
 			map[i].handle = SCSIBACK_INVALID_HANDLE;
 			err = -ENOMEM;
 		} else {
@@ -449,7 +448,7 @@ static int scsiback_gnttab_data_map_list(struct vscsibk_pend *pending_req,
 	for (i = 0; i < cnt; i++) {
 		if (get_free_page(pg + mapcount)) {
 			put_free_pages(pg, mapcount);
-			pr_err("xen-pvscsi: no grant page\n");
+			pr_err("no grant page\n");
 			return -ENOMEM;
 		}
 		gnttab_set_map_op(&map[mapcount], vaddr_page(pg[mapcount]),
@@ -492,7 +491,7 @@ static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 		return 0;
 
 	if (nr_segments > VSCSIIF_SG_TABLESIZE) {
-		DPRINTK("xen-pvscsi: invalid parameter nr_seg = %d\n",
+		pr_debug("invalid parameter nr_seg = %d\n",
 			ring_req->nr_segments);
 		return -EINVAL;
 	}
@@ -516,13 +515,12 @@ static int scsiback_gnttab_data_map(struct vscsiif_request *ring_req,
 			nr_segments += n_segs;
 		}
 		if (nr_segments > SG_ALL) {
-			DPRINTK("xen-pvscsi: invalid nr_seg = %d\n",
-				nr_segments);
+			pr_debug("invalid nr_seg = %d\n", nr_segments);
 			return -EINVAL;
 		}
 	}
 
-	/* free of (sgl) in fast_flush_area()*/
+	/* free of (sgl) in fast_flush_area() */
 	pending_req->sgl = kmalloc_array(nr_segments,
 					sizeof(struct scatterlist), GFP_KERNEL);
 	if (!pending_req->sgl)
@@ -679,7 +677,8 @@ static int prepare_pending_reqs(struct vscsibk_info *info,
 	v2p = scsiback_do_translation(info, &vir);
 	if (!v2p) {
 		pending_req->v2p = NULL;
-		DPRINTK("xen-pvscsi: doesn't exist.\n");
+		pr_debug("the v2p of (chn:%d, tgt:%d, lun:%d) doesn't exist.\n",
+			vir.chn, vir.tgt, vir.lun);
 		return -ENODEV;
 	}
 	pending_req->v2p = v2p;
@@ -690,14 +689,14 @@ static int prepare_pending_reqs(struct vscsibk_info *info,
 		(pending_req->sc_data_direction != DMA_TO_DEVICE) &&
 		(pending_req->sc_data_direction != DMA_FROM_DEVICE) &&
 		(pending_req->sc_data_direction != DMA_NONE)) {
-		DPRINTK("xen-pvscsi: invalid parameter data_dir = %d\n",
+		pr_debug("invalid parameter data_dir = %d\n",
 			pending_req->sc_data_direction);
 		return -EINVAL;
 	}
 
 	pending_req->cmd_len = ring_req->cmd_len;
 	if (pending_req->cmd_len > VSCSIIF_MAX_COMMAND_SIZE) {
-		DPRINTK("xen-pvscsi: invalid parameter cmd_len = %d\n",
+		pr_debug("invalid parameter cmd_len = %d\n",
 			pending_req->cmd_len);
 		return -EINVAL;
 	}
@@ -721,7 +720,7 @@ static int scsiback_do_cmd_fn(struct vscsibk_info *info)
 
 	if (RING_REQUEST_PROD_OVERFLOW(ring, rp)) {
 		rc = ring->rsp_prod_pvt;
-		pr_warn("xen-pvscsi: Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
+		pr_warn("Dom%d provided bogus ring requests (%#x - %#x = %u). Halting ring processing\n",
 			   info->domid, rp, rc, rp - rc);
 		info->ring_error = 1;
 		return 0;
@@ -772,7 +771,7 @@ static int scsiback_do_cmd_fn(struct vscsibk_info *info)
 			scsiback_device_action(pending_req, TMR_LUN_RESET, 0);
 			break;
 		default:
-			pr_err_ratelimited("xen-pvscsi: invalid request\n");
+			pr_err_ratelimited("invalid request\n");
 			scsiback_do_resp_with_sense(NULL, DRIVER_ERROR << 24,
 						    0, pending_req);
 			kmem_cache_free(scsiback_cachep, pending_req);
@@ -810,7 +809,7 @@ static int scsiback_init_sring(struct vscsibk_info *info, grant_ref_t ring_ref,
 	if (info->irq)
 		return -1;
 
-	err = xenbus_map_ring_valloc(info->dev, ring_ref, &area);
+	err = xenbus_map_ring_valloc(info->dev, &ring_ref, 1, &area);
 	if (err)
 		return err;
 
@@ -874,14 +873,13 @@ static int scsiback_add_translation_entry(struct vscsibk_info *info,
 
 	lunp = strrchr(phy, ':');
 	if (!lunp) {
-		pr_err("xen-pvscsi: illegal format of physical device %s\n",
-			phy);
+		pr_err("illegal format of physical device %s\n", phy);
 		return -EINVAL;
 	}
 	*lunp = 0;
 	lunp++;
 	if (kstrtouint(lunp, 10, &lun) || lun >= TRANSPORT_MAX_LUNS_PER_TPG) {
-		pr_err("xen-pvscsi: lun number not valid: %s\n", lunp);
+		pr_err("lun number not valid: %s\n", lunp);
 		return -EINVAL;
 	}
 
@@ -909,7 +907,7 @@ static int scsiback_add_translation_entry(struct vscsibk_info *info,
 	mutex_unlock(&scsiback_mutex);
 
 	if (!tpg) {
-		pr_err("xen-pvscsi: %s:%d %s\n", phy, lun, error);
+		pr_err("%s:%d %s\n", phy, lun, error);
 		return -ENODEV;
 	}
 
@@ -926,7 +924,7 @@ static int scsiback_add_translation_entry(struct vscsibk_info *info,
 		if ((entry->v.chn == v->chn) &&
 		    (entry->v.tgt == v->tgt) &&
 		    (entry->v.lun == v->lun)) {
-			pr_warn("xen-pvscsi: Virtual ID is already used. Assignment was not performed.\n");
+			pr_warn("Virtual ID is already used. Assignment was not performed.\n");
 			err = -EEXIST;
 			goto out;
 		}
@@ -992,15 +990,15 @@ found:
 }
 
 static void scsiback_do_add_lun(struct vscsibk_info *info, const char *state,
-				char *phy, struct ids_tuple *vir)
+				char *phy, struct ids_tuple *vir, int try)
 {
 	if (!scsiback_add_translation_entry(info, phy, vir)) {
 		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
 				  "%d", XenbusStateInitialised)) {
-			pr_err("xen-pvscsi: xenbus_printf error %s\n", state);
+			pr_err("xenbus_printf error %s\n", state);
 			scsiback_del_translation_entry(info, vir);
 		}
-	} else {
+	} else if (!try) {
 		xenbus_printf(XBT_NIL, info->dev->nodename, state,
 			      "%d", XenbusStateClosed);
 	}
@@ -1012,7 +1010,7 @@ static void scsiback_do_del_lun(struct vscsibk_info *info, const char *state,
 	if (!scsiback_del_translation_entry(info, vir)) {
 		if (xenbus_printf(XBT_NIL, info->dev->nodename, state,
 				  "%d", XenbusStateClosed))
-			pr_err("xen-pvscsi: xenbus_printf error %s\n", state);
+			pr_err("xenbus_printf error %s\n", state);
 	}
 }
 
@@ -1060,10 +1058,19 @@ static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
 
 	switch (op) {
 	case VSCSIBACK_OP_ADD_OR_DEL_LUN:
-		if (device_state == XenbusStateInitialising)
-			scsiback_do_add_lun(info, state, phy, &vir);
-		if (device_state == XenbusStateClosing)
+		switch (device_state) {
+		case XenbusStateInitialising:
+			scsiback_do_add_lun(info, state, phy, &vir, 0);
+			break;
+		case XenbusStateConnected:
+			scsiback_do_add_lun(info, state, phy, &vir, 1);
+			break;
+		case XenbusStateClosing:
 			scsiback_do_del_lun(info, state, &vir);
+			break;
+		default:
+			break;
+		}
 		break;
 
 	case VSCSIBACK_OP_UPDATEDEV_STATE:
@@ -1071,15 +1078,14 @@ static void scsiback_do_1lun_hotplug(struct vscsibk_info *info, int op,
 			/* modify vscsi-devs/dev-x/state */
 			if (xenbus_printf(XBT_NIL, dev->nodename, state,
 					  "%d", XenbusStateConnected)) {
-				pr_err("xen-pvscsi: xenbus_printf error %s\n",
-				       str);
+				pr_err("xenbus_printf error %s\n", str);
 				scsiback_del_translation_entry(info, &vir);
 				xenbus_printf(XBT_NIL, dev->nodename, state,
 					      "%d", XenbusStateClosed);
 			}
 		}
 		break;
-	/*When it is necessary, processing is added here.*/
+	/* When it is necessary, processing is added here. */
 	default:
 		break;
 	}
@@ -1196,7 +1202,7 @@ static int scsiback_probe(struct xenbus_device *dev,
 	struct vscsibk_info *info = kzalloc(sizeof(struct vscsibk_info),
 					    GFP_KERNEL);
 
-	DPRINTK("%p %d\n", dev, dev->otherend_id);
+	pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
 
 	if (!info) {
 		xenbus_dev_fatal(dev, -ENOMEM, "allocating backend structure");
@@ -1227,7 +1233,7 @@ static int scsiback_probe(struct xenbus_device *dev,
 	return 0;
 
 fail:
-	pr_warn("xen-pvscsi: %s failed\n", __func__);
+	pr_warn("%s failed\n", __func__);
 	scsiback_remove(dev);
 
 	return err;
@@ -1432,7 +1438,7 @@ check_len:
 	}
 	snprintf(&tport->tport_name[0], VSCSI_NAMELEN, "%s", &name[off]);
 
-	pr_debug("xen-pvscsi: Allocated emulated Target %s Address: %s\n",
+	pr_debug("Allocated emulated Target %s Address: %s\n",
 		 scsiback_dump_proto_id(tport), name);
 
 	return &tport->tport_wwn;
@@ -1443,7 +1449,7 @@ static void scsiback_drop_tport(struct se_wwn *wwn)
 	struct scsiback_tport *tport = container_of(wwn,
 				struct scsiback_tport, tport_wwn);
 
-	pr_debug("xen-pvscsi: Deallocating emulated Target %s Address: %s\n",
+	pr_debug("Deallocating emulated Target %s Address: %s\n",
 		 scsiback_dump_proto_id(tport), tport->tport_name);
 
 	kfree(tport);
@@ -1470,8 +1476,8 @@ static u32 scsiback_tpg_get_inst_index(struct se_portal_group *se_tpg)
 static int scsiback_check_stop_free(struct se_cmd *se_cmd)
 {
 	/*
-	 * Do not release struct se_cmd's containing a valid TMR
-	 * pointer.  These will be released directly in scsiback_device_action()
+	 * Do not release struct se_cmd's containing a valid TMR pointer.
+	 * These will be released directly in scsiback_device_action()
 	 * with transport_generic_free_cmd().
 	 */
 	if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
@@ -1637,7 +1643,7 @@ static int scsiback_make_nexus(struct scsiback_tpg *tpg,
 		return -ENOMEM;
 	}
 	/*
-	 *  Initialize the struct se_session pointer
+	 * Initialize the struct se_session pointer
 	 */
 	tv_nexus->tvn_se_sess = transport_init_session(TARGET_PROT_NORMAL);
 	if (IS_ERR(tv_nexus->tvn_se_sess)) {
@@ -1705,7 +1711,7 @@ static int scsiback_drop_nexus(struct scsiback_tpg *tpg)
 		return -EBUSY;
 	}
 
-	pr_debug("xen-pvscsi: Removing I_T Nexus to emulated %s Initiator Port: %s\n",
+	pr_debug("Removing I_T Nexus to emulated %s Initiator Port: %s\n",
 		scsiback_dump_proto_id(tpg->tport),
 		tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
 
@@ -1751,7 +1757,7 @@ static ssize_t scsiback_tpg_store_nexus(struct se_portal_group *se_tpg,
 	unsigned char i_port[VSCSI_NAMELEN], *ptr, *port_ptr;
 	int ret;
 	/*
-	 * Shutdown the active I_T nexus if 'NULL' is passed..
+	 * Shutdown the active I_T nexus if 'NULL' is passed.
 	 */
 	if (!strncmp(page, "NULL", 4)) {
 		ret = scsiback_drop_nexus(tpg);
@@ -1922,7 +1928,7 @@ static void scsiback_drop_tpg(struct se_portal_group *se_tpg)
 	 */
 	scsiback_drop_nexus(tpg);
 	/*
-	 * Deregister the se_tpg from TCM..
+	 * Deregister the se_tpg from TCM.
 	 */
 	core_tpg_deregister(se_tpg);
 	kfree(tpg);
@@ -1992,7 +1998,7 @@ static int scsiback_register_configfs(void)
 	struct target_fabric_configfs *fabric;
 	int ret;
 
-	pr_debug("xen-pvscsi: fabric module %s on %s/%s on "UTS_RELEASE"\n",
+	pr_debug("fabric module %s on %s/%s on "UTS_RELEASE"\n",
 		 VSCSI_VERSION, utsname()->sysname, utsname()->machine);
 	/*
 	 * Register the top level struct config_item_type with TCM core
@@ -2029,7 +2035,7 @@ static int scsiback_register_configfs(void)
 	 * Setup our local pointer to *fabric
 	 */
 	scsiback_fabric_configfs = fabric;
-	pr_debug("xen-pvscsi: Set fabric -> scsiback_fabric_configfs\n");
+	pr_debug("Set fabric -> scsiback_fabric_configfs\n");
 	return 0;
 };
 
@@ -2040,7 +2046,7 @@ static void scsiback_deregister_configfs(void)
 
 	target_fabric_configfs_deregister(scsiback_fabric_configfs);
 	scsiback_fabric_configfs = NULL;
-	pr_debug("xen-pvscsi: Cleared scsiback_fabric_configfs\n");
+	pr_debug("Cleared scsiback_fabric_configfs\n");
 };
 
 static const struct xenbus_device_id scsiback_ids[] = {
@@ -2091,7 +2097,7 @@ out_unregister_xenbus:
 	xenbus_unregister_driver(&scsiback_driver);
 out_cache_destroy:
 	kmem_cache_destroy(scsiback_cachep);
-	pr_err("xen-pvscsi: %s: error %d\n", __func__, ret);
+	pr_err("%s: error %d\n", __func__, ret);
 	return ret;
 }
 
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index ca74410..96b2011 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -52,17 +52,25 @@
 struct xenbus_map_node {
 	struct list_head next;
 	union {
-		struct vm_struct *area; /* PV */
-		struct page *page;     /* HVM */
+		struct {
+			struct vm_struct *area;
+		} pv;
+		struct {
+			struct page *pages[XENBUS_MAX_RING_PAGES];
+			void *addr;
+		} hvm;
 	};
-	grant_handle_t handle;
+	grant_handle_t handles[XENBUS_MAX_RING_PAGES];
+	unsigned int   nr_handles;
 };
 
 static DEFINE_SPINLOCK(xenbus_valloc_lock);
 static LIST_HEAD(xenbus_valloc_pages);
 
 struct xenbus_ring_ops {
-	int (*map)(struct xenbus_device *dev, int gnt, void **vaddr);
+	int (*map)(struct xenbus_device *dev,
+		   grant_ref_t *gnt_refs, unsigned int nr_grefs,
+		   void **vaddr);
 	int (*unmap)(struct xenbus_device *dev, void *vaddr);
 };
 
@@ -355,17 +363,39 @@ static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err,
 /**
  * xenbus_grant_ring
  * @dev: xenbus device
- * @ring_mfn: mfn of ring to grant
-
- * Grant access to the given @ring_mfn to the peer of the given device.  Return
- * a grant reference on success, or -errno on error. On error, the device will
- * switch to XenbusStateClosing, and the error will be saved in the store.
+ * @vaddr: starting virtual address of the ring
+ * @nr_pages: number of pages to be granted
+ * @grefs: grant reference array to be filled in
+ *
+ * Grant access to the given @vaddr to the peer of the given device.
+ * Then fill in @grefs with grant references.  Return 0 on success, or
+ * -errno on error.  On error, the device will switch to
+ * XenbusStateClosing, and the error will be saved in the store.
  */
-int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn)
+int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
+		      unsigned int nr_pages, grant_ref_t *grefs)
 {
-	int err = gnttab_grant_foreign_access(dev->otherend_id, ring_mfn, 0);
-	if (err < 0)
-		xenbus_dev_fatal(dev, err, "granting access to ring page");
+	int err;
+	int i, j;
+
+	for (i = 0; i < nr_pages; i++) {
+		unsigned long addr = (unsigned long)vaddr +
+			(PAGE_SIZE * i);
+		err = gnttab_grant_foreign_access(dev->otherend_id,
+						  virt_to_mfn(addr), 0);
+		if (err < 0) {
+			xenbus_dev_fatal(dev, err,
+					 "granting access to ring page");
+			goto fail;
+		}
+		grefs[i] = err;
+	}
+
+	return 0;
+
+fail:
+	for (j = 0; j < i; j++)
+		gnttab_end_foreign_access_ref(grefs[j], 0);
 	return err;
 }
 EXPORT_SYMBOL_GPL(xenbus_grant_ring);
@@ -419,62 +449,130 @@ EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
 /**
  * xenbus_map_ring_valloc
  * @dev: xenbus device
- * @gnt_ref: grant reference
+ * @gnt_refs: grant reference array
+ * @nr_grefs: number of grant references
  * @vaddr: pointer to address to be filled out by mapping
  *
- * Based on Rusty Russell's skeleton driver's map_page.
- * Map a page of memory into this domain from another domain's grant table.
- * xenbus_map_ring_valloc allocates a page of virtual address space, maps the
- * page to that address, and sets *vaddr to that address.
- * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
- * or -ENOMEM on error. If an error is returned, device will switch to
+ * Map @nr_grefs pages of memory into this domain from another
+ * domain's grant table.  xenbus_map_ring_valloc allocates @nr_grefs
+ * pages of virtual address space, maps the pages to that address, and
+ * sets *vaddr to that address.  Returns 0 on success, and GNTST_*
+ * (see xen/include/interface/grant_table.h) or -ENOMEM / -EINVAL on
+ * error. If an error is returned, device will switch to
  * XenbusStateClosing and the error message will be saved in XenStore.
  */
-int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
+int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
+			   unsigned int nr_grefs, void **vaddr)
 {
-	return ring_ops->map(dev, gnt_ref, vaddr);
+	return ring_ops->map(dev, gnt_refs, nr_grefs, vaddr);
 }
 EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);
 
+/* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned
+ * long), e.g. 32-on-64.  Caller is responsible for preparing the
+ * right array to feed into this function */
+static int __xenbus_map_ring(struct xenbus_device *dev,
+			     grant_ref_t *gnt_refs,
+			     unsigned int nr_grefs,
+			     grant_handle_t *handles,
+			     phys_addr_t *addrs,
+			     unsigned int flags,
+			     bool *leaked)
+{
+	struct gnttab_map_grant_ref map[XENBUS_MAX_RING_PAGES];
+	struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_PAGES];
+	int i, j;
+	int err = GNTST_okay;
+
+	if (nr_grefs > XENBUS_MAX_RING_PAGES)
+		return -EINVAL;
+
+	for (i = 0; i < nr_grefs; i++) {
+		memset(&map[i], 0, sizeof(map[i]));
+		gnttab_set_map_op(&map[i], addrs[i], flags, gnt_refs[i],
+				  dev->otherend_id);
+		handles[i] = INVALID_GRANT_HANDLE;
+	}
+
+	gnttab_batch_map(map, i);
+
+	for (i = 0; i < nr_grefs; i++) {
+		if (map[i].status != GNTST_okay) {
+			err = map[i].status;
+			xenbus_dev_fatal(dev, map[i].status,
+					 "mapping in shared page %d from domain %d",
+					 gnt_refs[i], dev->otherend_id);
+			goto fail;
+		} else
+			handles[i] = map[i].handle;
+	}
+
+	return GNTST_okay;
+
+ fail:
+	for (i = j = 0; i < nr_grefs; i++) {
+		if (handles[i] != INVALID_GRANT_HANDLE) {
+			memset(&unmap[j], 0, sizeof(unmap[j]));
+			gnttab_set_unmap_op(&unmap[j], (phys_addr_t)addrs[i],
+					    GNTMAP_host_map, handles[i]);
+			j++;
+		}
+	}
+
+	if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, j))
+		BUG();
+
+	*leaked = false;
+	for (i = 0; i < j; i++) {
+		if (unmap[i].status != GNTST_okay) {
+			*leaked = true;
+			break;
+		}
+	}
+
+	return err;
+}
+
 static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
-				     int gnt_ref, void **vaddr)
+				     grant_ref_t *gnt_refs,
+				     unsigned int nr_grefs,
+				     void **vaddr)
 {
-	struct gnttab_map_grant_ref op = {
-		.flags = GNTMAP_host_map | GNTMAP_contains_pte,
-		.ref   = gnt_ref,
-		.dom   = dev->otherend_id,
-	};
 	struct xenbus_map_node *node;
 	struct vm_struct *area;
-	pte_t *pte;
+	pte_t *ptes[XENBUS_MAX_RING_PAGES];
+	phys_addr_t phys_addrs[XENBUS_MAX_RING_PAGES];
+	int err = GNTST_okay;
+	int i;
+	bool leaked;
 
 	*vaddr = NULL;
 
+	if (nr_grefs > XENBUS_MAX_RING_PAGES)
+		return -EINVAL;
+
 	node = kzalloc(sizeof(*node), GFP_KERNEL);
 	if (!node)
 		return -ENOMEM;
 
-	area = alloc_vm_area(PAGE_SIZE, &pte);
+	area = alloc_vm_area(PAGE_SIZE * nr_grefs, ptes);
 	if (!area) {
 		kfree(node);
 		return -ENOMEM;
 	}
 
-	op.host_addr = arbitrary_virt_to_machine(pte).maddr;
+	for (i = 0; i < nr_grefs; i++)
+		phys_addrs[i] = arbitrary_virt_to_machine(ptes[i]).maddr;
 
-	gnttab_batch_map(&op, 1);
-
-	if (op.status != GNTST_okay) {
-		free_vm_area(area);
-		kfree(node);
-		xenbus_dev_fatal(dev, op.status,
-				 "mapping in shared page %d from domain %d",
-				 gnt_ref, dev->otherend_id);
-		return op.status;
-	}
+	err = __xenbus_map_ring(dev, gnt_refs, nr_grefs, node->handles,
+				phys_addrs,
+				GNTMAP_host_map | GNTMAP_contains_pte,
+				&leaked);
+	if (err)
+		goto failed;
 
-	node->handle = op.handle;
-	node->area = area;
+	node->nr_handles = nr_grefs;
+	node->pv.area = area;
 
 	spin_lock(&xenbus_valloc_lock);
 	list_add(&node->next, &xenbus_valloc_pages);
@@ -482,14 +580,33 @@ static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
 
 	*vaddr = area->addr;
 	return 0;
+
+failed:
+	if (!leaked)
+		free_vm_area(area);
+	else
+		pr_alert("leaking VM area %p size %u page(s)", area, nr_grefs);
+
+	kfree(node);
+	return err;
 }
 
 static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
-				      int gnt_ref, void **vaddr)
+				      grant_ref_t *gnt_ref,
+				      unsigned int nr_grefs,
+				      void **vaddr)
 {
 	struct xenbus_map_node *node;
+	int i;
 	int err;
 	void *addr;
+	bool leaked = false;
+	/* Why do we need two arrays? See comment of __xenbus_map_ring */
+	phys_addr_t phys_addrs[XENBUS_MAX_RING_PAGES];
+	unsigned long addrs[XENBUS_MAX_RING_PAGES];
+
+	if (nr_grefs > XENBUS_MAX_RING_PAGES)
+		return -EINVAL;
 
 	*vaddr = NULL;
 
@@ -497,15 +614,32 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
 	if (!node)
 		return -ENOMEM;
 
-	err = alloc_xenballooned_pages(1, &node->page, false /* lowmem */);
+	err = alloc_xenballooned_pages(nr_grefs, node->hvm.pages,
+				       false /* lowmem */);
 	if (err)
 		goto out_err;
 
-	addr = pfn_to_kaddr(page_to_pfn(node->page));
+	for (i = 0; i < nr_grefs; i++) {
+		unsigned long pfn = page_to_pfn(node->hvm.pages[i]);
+		phys_addrs[i] = (unsigned long)pfn_to_kaddr(pfn);
+		addrs[i] = (unsigned long)pfn_to_kaddr(pfn);
+	}
+
+	err = __xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handles,
+				phys_addrs, GNTMAP_host_map, &leaked);
+	node->nr_handles = nr_grefs;
 
-	err = xenbus_map_ring(dev, gnt_ref, &node->handle, addr);
 	if (err)
-		goto out_err_free_ballooned_pages;
+		goto out_free_ballooned_pages;
+
+	addr = vmap(node->hvm.pages, nr_grefs, VM_MAP | VM_IOREMAP,
+		    PAGE_KERNEL);
+	if (!addr) {
+		err = -ENOMEM;
+		goto out_xenbus_unmap_ring;
+	}
+
+	node->hvm.addr = addr;
 
 	spin_lock(&xenbus_valloc_lock);
 	list_add(&node->next, &xenbus_valloc_pages);
@@ -514,8 +648,16 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
 	*vaddr = addr;
 	return 0;
 
- out_err_free_ballooned_pages:
-	free_xenballooned_pages(1, &node->page);
+ out_xenbus_unmap_ring:
+	if (!leaked)
+		xenbus_unmap_ring(dev, node->handles, node->nr_handles,
+				  addrs);
+	else
+		pr_alert("leaking %p size %u page(s)",
+			 addr, nr_grefs);
+ out_free_ballooned_pages:
+	if (!leaked)
+		free_xenballooned_pages(nr_grefs, node->hvm.pages);
  out_err:
 	kfree(node);
 	return err;
@@ -525,35 +667,37 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
 /**
  * xenbus_map_ring
  * @dev: xenbus device
- * @gnt_ref: grant reference
- * @handle: pointer to grant handle to be filled
- * @vaddr: address to be mapped to
+ * @gnt_refs: grant reference array
+ * @nr_grefs: number of grant reference
+ * @handles: pointer to grant handle to be filled
+ * @vaddrs: addresses to be mapped to
+ * @leaked: fail to clean up a failed map, caller should not free vaddr
  *
- * Map a page of memory into this domain from another domain's grant table.
+ * Map pages of memory into this domain from another domain's grant table.
  * xenbus_map_ring does not allocate the virtual address space (you must do
- * this yourself!). It only maps in the page to the specified address.
+ * this yourself!). It only maps in the pages to the specified address.
  * Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
- * or -ENOMEM on error. If an error is returned, device will switch to
- * XenbusStateClosing and the error message will be saved in XenStore.
+ * or -ENOMEM / -EINVAL on error. If an error is returned, device will switch to
+ * XenbusStateClosing and the first error message will be saved in XenStore.
+ * Further more if we fail to map the ring, caller should check @leaked.
+ * If @leaked is not zero it means xenbus_map_ring fails to clean up, caller
+ * should not free the address space of @vaddr.
  */
-int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
-		    grant_handle_t *handle, void *vaddr)
+int xenbus_map_ring(struct xenbus_device *dev, grant_ref_t *gnt_refs,
+		    unsigned int nr_grefs, grant_handle_t *handles,
+		    unsigned long *vaddrs, bool *leaked)
 {
-	struct gnttab_map_grant_ref op;
-
-	gnttab_set_map_op(&op, (unsigned long)vaddr, GNTMAP_host_map, gnt_ref,
-			  dev->otherend_id);
+	phys_addr_t phys_addrs[XENBUS_MAX_RING_PAGES];
+	int i;
 
-	gnttab_batch_map(&op, 1);
+	if (nr_grefs > XENBUS_MAX_RING_PAGES)
+		return -EINVAL;
 
-	if (op.status != GNTST_okay) {
-		xenbus_dev_fatal(dev, op.status,
-				 "mapping in shared page %d from domain %d",
-				 gnt_ref, dev->otherend_id);
-	} else
-		*handle = op.handle;
+	for (i = 0; i < nr_grefs; i++)
+		phys_addrs[i] = (unsigned long)vaddrs[i];
 
-	return op.status;
+	return __xenbus_map_ring(dev, gnt_refs, nr_grefs, handles,
+				 phys_addrs, GNTMAP_host_map, leaked);
 }
 EXPORT_SYMBOL_GPL(xenbus_map_ring);
 
@@ -579,14 +723,15 @@ EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);
 static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
 {
 	struct xenbus_map_node *node;
-	struct gnttab_unmap_grant_ref op = {
-		.host_addr = (unsigned long)vaddr,
-	};
+	struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_PAGES];
 	unsigned int level;
+	int i;
+	bool leaked = false;
+	int err;
 
 	spin_lock(&xenbus_valloc_lock);
 	list_for_each_entry(node, &xenbus_valloc_pages, next) {
-		if (node->area->addr == vaddr) {
+		if (node->pv.area->addr == vaddr) {
 			list_del(&node->next);
 			goto found;
 		}
@@ -601,22 +746,41 @@ static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
 		return GNTST_bad_virt_addr;
 	}
 
-	op.handle = node->handle;
-	op.host_addr = arbitrary_virt_to_machine(
-		lookup_address((unsigned long)vaddr, &level)).maddr;
+	for (i = 0; i < node->nr_handles; i++) {
+		unsigned long addr;
+
+		memset(&unmap[i], 0, sizeof(unmap[i]));
+		addr = (unsigned long)vaddr + (PAGE_SIZE * i);
+		unmap[i].host_addr = arbitrary_virt_to_machine(
+			lookup_address(addr, &level)).maddr;
+		unmap[i].dev_bus_addr = 0;
+		unmap[i].handle = node->handles[i];
+	}
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
+	if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
 		BUG();
 
-	if (op.status == GNTST_okay)
-		free_vm_area(node->area);
+	err = GNTST_okay;
+	leaked = false;
+	for (i = 0; i < node->nr_handles; i++) {
+		if (unmap[i].status != GNTST_okay) {
+			leaked = true;
+			xenbus_dev_error(dev, unmap[i].status,
+					 "unmapping page at handle %d error %d",
+					 node->handles[i], unmap[i].status);
+			err = unmap[i].status;
+			break;
+		}
+	}
+
+	if (!leaked)
+		free_vm_area(node->pv.area);
 	else
-		xenbus_dev_error(dev, op.status,
-				 "unmapping page at handle %d error %d",
-				 node->handle, op.status);
+		pr_alert("leaking VM area %p size %u page(s)",
+			 node->pv.area, node->nr_handles);
 
 	kfree(node);
-	return op.status;
+	return err;
 }
 
 static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
@@ -624,10 +788,12 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
 	int rv;
 	struct xenbus_map_node *node;
 	void *addr;
+	unsigned long addrs[XENBUS_MAX_RING_PAGES];
+	int i;
 
 	spin_lock(&xenbus_valloc_lock);
 	list_for_each_entry(node, &xenbus_valloc_pages, next) {
-		addr = pfn_to_kaddr(page_to_pfn(node->page));
+		addr = node->hvm.addr;
 		if (addr == vaddr) {
 			list_del(&node->next);
 			goto found;
@@ -643,12 +809,16 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
 		return GNTST_bad_virt_addr;
 	}
 
-	rv = xenbus_unmap_ring(dev, node->handle, addr);
+	for (i = 0; i < node->nr_handles; i++)
+		addrs[i] = (unsigned long)pfn_to_kaddr(page_to_pfn(node->hvm.pages[i]));
 
+	rv = xenbus_unmap_ring(dev, node->handles, node->nr_handles,
+			       addrs);
 	if (!rv)
-		free_xenballooned_pages(1, &node->page);
+		vunmap(vaddr);
 	else
-		WARN(1, "Leaking %p\n", vaddr);
+		WARN(1, "Leaking %p, size %u page(s)\n", vaddr,
+		     node->nr_handles);
 
 	kfree(node);
 	return rv;
@@ -657,29 +827,44 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
 /**
  * xenbus_unmap_ring
  * @dev: xenbus device
- * @handle: grant handle
- * @vaddr: addr to unmap
+ * @handles: grant handle array
+ * @nr_handles: number of handles in the array
+ * @vaddrs: addresses to unmap
  *
- * Unmap a page of memory in this domain that was imported from another domain.
+ * Unmap memory in this domain that was imported from another domain.
  * Returns 0 on success and returns GNTST_* on error
  * (see xen/include/interface/grant_table.h).
  */
 int xenbus_unmap_ring(struct xenbus_device *dev,
-		      grant_handle_t handle, void *vaddr)
+		      grant_handle_t *handles, unsigned int nr_handles,
+		      unsigned long *vaddrs)
 {
-	struct gnttab_unmap_grant_ref op;
+	struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_PAGES];
+	int i;
+	int err;
 
-	gnttab_set_unmap_op(&op, (unsigned long)vaddr, GNTMAP_host_map, handle);
+	if (nr_handles > XENBUS_MAX_RING_PAGES)
+		return -EINVAL;
 
-	if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
+	for (i = 0; i < nr_handles; i++)
+		gnttab_set_unmap_op(&unmap[i], vaddrs[i],
+				    GNTMAP_host_map, handles[i]);
+
+	if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, i))
 		BUG();
 
-	if (op.status != GNTST_okay)
-		xenbus_dev_error(dev, op.status,
-				 "unmapping page at handle %d error %d",
-				 handle, op.status);
+	err = GNTST_okay;
+	for (i = 0; i < nr_handles; i++) {
+		if (unmap[i].status != GNTST_okay) {
+			xenbus_dev_error(dev, unmap[i].status,
+					 "unmapping page at handle %d error %d",
+					 handles[i], unmap[i].status);
+			err = unmap[i].status;
+			break;
+		}
+	}
 
-	return op.status;
+	return err;
 }
 EXPORT_SYMBOL_GPL(xenbus_unmap_ring);
 
diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
new file mode 100644
index 0000000..58a5389
--- /dev/null
+++ b/drivers/xen/xlate_mmu.c
@@ -0,0 +1,143 @@
+/*
+ * MMU operations common to all auto-translated physmap guests.
+ *
+ * Copyright (C) 2015 Citrix Systems R&D Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+#include <linux/kernel.h>
+#include <linux/mm.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/page.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/memory.h>
+
+/* map fgmfn of domid to lpfn in the current domain */
+static int map_foreign_page(unsigned long lpfn, unsigned long fgmfn,
+			    unsigned int domid)
+{
+	int rc;
+	struct xen_add_to_physmap_range xatp = {
+		.domid = DOMID_SELF,
+		.foreign_domid = domid,
+		.size = 1,
+		.space = XENMAPSPACE_gmfn_foreign,
+	};
+	xen_ulong_t idx = fgmfn;
+	xen_pfn_t gpfn = lpfn;
+	int err = 0;
+
+	set_xen_guest_handle(xatp.idxs, &idx);
+	set_xen_guest_handle(xatp.gpfns, &gpfn);
+	set_xen_guest_handle(xatp.errs, &err);
+
+	rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
+	return rc < 0 ? rc : err;
+}
+
+struct remap_data {
+	xen_pfn_t *fgmfn; /* foreign domain's gmfn */
+	pgprot_t prot;
+	domid_t  domid;
+	struct vm_area_struct *vma;
+	int index;
+	struct page **pages;
+	struct xen_remap_mfn_info *info;
+	int *err_ptr;
+	int mapped;
+};
+
+static int remap_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
+			void *data)
+{
+	struct remap_data *info = data;
+	struct page *page = info->pages[info->index++];
+	unsigned long pfn = page_to_pfn(page);
+	pte_t pte = pte_mkspecial(pfn_pte(pfn, info->prot));
+	int rc;
+
+	rc = map_foreign_page(pfn, *info->fgmfn, info->domid);
+	*info->err_ptr++ = rc;
+	if (!rc) {
+		set_pte_at(info->vma->vm_mm, addr, ptep, pte);
+		info->mapped++;
+	}
+	info->fgmfn++;
+
+	return 0;
+}
+
+int xen_xlate_remap_gfn_array(struct vm_area_struct *vma,
+			      unsigned long addr,
+			      xen_pfn_t *mfn, int nr,
+			      int *err_ptr, pgprot_t prot,
+			      unsigned domid,
+			      struct page **pages)
+{
+	int err;
+	struct remap_data data;
+	unsigned long range = nr << PAGE_SHIFT;
+
+	/* Kept here for the purpose of making sure code doesn't break
+	   x86 PVOPS */
+	BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
+
+	data.fgmfn = mfn;
+	data.prot  = prot;
+	data.domid = domid;
+	data.vma   = vma;
+	data.pages = pages;
+	data.index = 0;
+	data.err_ptr = err_ptr;
+	data.mapped = 0;
+
+	err = apply_to_page_range(vma->vm_mm, addr, range,
+				  remap_pte_fn, &data);
+	return err < 0 ? err : data.mapped;
+}
+EXPORT_SYMBOL_GPL(xen_xlate_remap_gfn_array);
+
+int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,
+			      int nr, struct page **pages)
+{
+	int i;
+
+	for (i = 0; i < nr; i++) {
+		struct xen_remove_from_physmap xrp;
+		unsigned long pfn;
+
+		pfn = page_to_pfn(pages[i]);
+
+		xrp.domid = DOMID_SELF;
+		xrp.gpfn = pfn;
+		(void)HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &xrp);
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xen_xlate_unmap_gfn_range);