1 files changed, 441 insertions, 0 deletions

diff --git a/src/pc-bios/s390-ccw/virtio.c b/src/pc-bios/s390-ccw/virtio.c
new file mode 100644
index 0000000..87aed38
--- /dev/null
+++ b/src/pc-bios/s390-ccw/virtio.c
@@ -0,0 +1,441 @@
+/*
+ * Virtio driver bits
+ *
+ * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or (at
+ * your option) any later version. See the COPYING file in the top-level
+ * directory.
+ */
+
+#include "s390-ccw.h"
+#include "virtio.h"
+
+static struct vring block;
+
+static char chsc_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
+
+static long kvm_hypercall(unsigned long nr, unsigned long param1,
+                          unsigned long param2)
+{
+    register ulong r_nr asm("1") = nr;
+    register ulong r_param1 asm("2") = param1;
+    register ulong r_param2 asm("3") = param2;
+    register long retval asm("2");
+
+    asm volatile ("diag 2,4,0x500"
+                  : "=d" (retval)
+                  : "d" (r_nr), "0" (r_param1), "r"(r_param2)
+                  : "memory", "cc");
+
+    return retval;
+}
+
+static void virtio_notify(struct subchannel_id schid)
+{
+    kvm_hypercall(KVM_S390_VIRTIO_CCW_NOTIFY, *(u32 *)&schid, 0);
+}
+
+/***********************************************
+ *             Virtio functions                *
+ ***********************************************/
+
+static int drain_irqs(struct subchannel_id schid)
+{
+    struct irb irb = {};
+    int r = 0;
+
+    while (1) {
+        /* FIXME: make use of TPI, for that enable subchannel and isc */
+        if (tsch(schid, &irb)) {
+            /* Might want to differentiate error codes later on. */
+            if (irb.scsw.cstat) {
+                r = -EIO;
+            } else if (irb.scsw.dstat != 0xc) {
+                r = -EIO;
+            }
+            return r;
+        }
+    }
+}
+
+static int run_ccw(struct subchannel_id schid, int cmd, void *ptr, int len)
+{
+    struct ccw1 ccw = {};
+    struct cmd_orb orb = {};
+    struct schib schib;
+    int r;
+
+    /* start command processing */
+    stsch_err(schid, &schib);
+    schib.scsw.ctrl = SCSW_FCTL_START_FUNC;
+    msch(schid, &schib);
+
+    /* start subchannel command */
+    orb.fmt = 1;
+    orb.cpa = (u32)(long)&ccw;
+    orb.lpm = 0x80;
+
+    ccw.cmd_code = cmd;
+    ccw.cda = (long)ptr;
+    ccw.count = len;
+
+    r = ssch(schid, &orb);
+    /*
+     * XXX Wait until device is done processing the CCW. For now we can
+     *     assume that a simple tsch will have finished the CCW processing,
+     *     but the architecture allows for asynchronous operation
+     */
+    if (!r) {
+        r = drain_irqs(schid);
+    }
+    return r;
+}
+
+static void virtio_set_status(struct subchannel_id schid,
+                              unsigned long dev_addr)
+{
+    unsigned char status = dev_addr;
+    if (run_ccw(schid, CCW_CMD_WRITE_STATUS, &status, sizeof(status))) {
+        virtio_panic("Could not write status to host!\n");
+    }
+}
+
+static void virtio_reset(struct subchannel_id schid)
+{
+    run_ccw(schid, CCW_CMD_VDEV_RESET, NULL, 0);
+}
+
+static void vring_init(struct vring *vr, unsigned int num, void *p,
+                       unsigned long align)
+{
+    debug_print_addr("init p", p);
+    vr->num = num;
+    vr->desc = p;
+    vr->avail = p + num*sizeof(struct vring_desc);
+    vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + align-1)
+                & ~(align - 1));
+
+    /* Zero out all relevant field */
+    vr->avail->flags = 0;
+    vr->avail->idx = 0;
+
+    /* We're running with interrupts off anyways, so don't bother */
+    vr->used->flags = VRING_USED_F_NO_NOTIFY;
+    vr->used->idx = 0;
+    vr->used_idx = 0;
+    vr->next_idx = 0;
+
+    debug_print_addr("init vr", vr);
+}
+
+static void vring_notify(struct subchannel_id schid)
+{
+    virtio_notify(schid);
+}
+
+static void vring_send_buf(struct vring *vr, void *p, int len, int flags)
+{
+    /* For follow-up chains we need to keep the first entry point */
+    if (!(flags & VRING_HIDDEN_IS_CHAIN)) {
+        vr->avail->ring[vr->avail->idx % vr->num] = vr->next_idx;
+    }
+
+    vr->desc[vr->next_idx].addr = (ulong)p;
+    vr->desc[vr->next_idx].len = len;
+    vr->desc[vr->next_idx].flags = flags & ~VRING_HIDDEN_IS_CHAIN;
+    vr->desc[vr->next_idx].next = vr->next_idx;
+    vr->desc[vr->next_idx].next++;
+    vr->next_idx++;
+
+    /* Chains only have a single ID */
+    if (!(flags & VRING_DESC_F_NEXT)) {
+        vr->avail->idx++;
+    }
+}
+
+static u64 get_clock(void)
+{
+    u64 r;
+
+    asm volatile("stck %0" : "=Q" (r) : : "cc");
+    return r;
+}
+
+static ulong get_second(void)
+{
+    return (get_clock() >> 12) / 1000000;
+}
+
+/*
+ * Wait for the host to reply.
+ *
+ * timeout is in seconds if > 0.
+ *
+ * Returns 0 on success, 1 on timeout.
+ */
+static int vring_wait_reply(struct vring *vr, int timeout)
+{
+    ulong target_second = get_second() + timeout;
+    struct subchannel_id schid = vr->schid;
+    int r = 0;
+
+    /* Wait until the used index has moved. */
+    while (vr->used->idx == vr->used_idx) {
+        vring_notify(schid);
+        if (timeout && (get_second() >= target_second)) {
+            r = 1;
+            break;
+        }
+        yield();
+    }
+
+    vr->used_idx = vr->used->idx;
+    vr->next_idx = 0;
+    vr->desc[0].len = 0;
+    vr->desc[0].flags = 0;
+
+    return r;
+}
+
+/***********************************************
+ *               Virtio block                  *
+ ***********************************************/
+
+int virtio_read_many(ulong sector, void *load_addr, int sec_num)
+{
+    struct virtio_blk_outhdr out_hdr;
+    u8 status;
+    int r;
+
+    /* Tell the host we want to read */
+    out_hdr.type = VIRTIO_BLK_T_IN;
+    out_hdr.ioprio = 99;
+    out_hdr.sector = virtio_sector_adjust(sector);
+
+    vring_send_buf(&block, &out_hdr, sizeof(out_hdr), VRING_DESC_F_NEXT);
+
+    /* This is where we want to receive data */
+    vring_send_buf(&block, load_addr, virtio_get_block_size() * sec_num,
+                   VRING_DESC_F_WRITE | VRING_HIDDEN_IS_CHAIN |
+                   VRING_DESC_F_NEXT);
+
+    /* status field */
+    vring_send_buf(&block, &status, sizeof(u8), VRING_DESC_F_WRITE |
+                   VRING_HIDDEN_IS_CHAIN);
+
+    /* Now we can tell the host to read */
+    vring_wait_reply(&block, 0);
+
+    r = drain_irqs(block.schid);
+    if (r) {
+        /* Well, whatever status is supposed to contain... */
+        status = 1;
+    }
+    return status;
+}
+
+unsigned long virtio_load_direct(ulong rec_list1, ulong rec_list2,
+                                 ulong subchan_id, void *load_addr)
+{
+    u8 status;
+    int sec = rec_list1;
+    int sec_num = ((rec_list2 >> 32) & 0xffff) + 1;
+    int sec_len = rec_list2 >> 48;
+    ulong addr = (ulong)load_addr;
+
+    if (sec_len != virtio_get_block_size()) {
+        return -1;
+    }
+
+    sclp_print(".");
+    status = virtio_read_many(sec, (void *)addr, sec_num);
+    if (status) {
+        virtio_panic("I/O Error");
+    }
+    addr += sec_num * virtio_get_block_size();
+
+    return addr;
+}
+
+int virtio_read(ulong sector, void *load_addr)
+{
+    return virtio_read_many(sector, load_addr, 1);
+}
+
+static VirtioBlkConfig blk_cfg = {};
+static bool guessed_disk_nature;
+
+bool virtio_guessed_disk_nature(void)
+{
+    return guessed_disk_nature;
+}
+
+void virtio_assume_scsi(void)
+{
+    guessed_disk_nature = true;
+    blk_cfg.blk_size = 512;
+    blk_cfg.physical_block_exp = 0;
+}
+
+void virtio_assume_iso9660(void)
+{
+    guessed_disk_nature = true;
+    blk_cfg.blk_size = 2048;
+    blk_cfg.physical_block_exp = 0;
+}
+
+void virtio_assume_eckd(void)
+{
+    guessed_disk_nature = true;
+    blk_cfg.blk_size = 4096;
+    blk_cfg.physical_block_exp = 0;
+
+    /* this must be here to calculate code segment position */
+    blk_cfg.geometry.heads = 15;
+    blk_cfg.geometry.sectors = 12;
+}
+
+bool virtio_disk_is_scsi(void)
+{
+    if (guessed_disk_nature) {
+        return (virtio_get_block_size()  == 512);
+    }
+    return (blk_cfg.geometry.heads == 255)
+        && (blk_cfg.geometry.sectors == 63)
+        && (virtio_get_block_size()  == 512);
+}
+
+/*
+ * Other supported value pairs, if any, would need to be added here.
+ * Note: head count is always 15.
+ */
+static inline u8 virtio_eckd_sectors_for_block_size(int size)
+{
+    switch (size) {
+    case 512:
+        return 49;
+    case 1024:
+        return 33;
+    case 2048:
+        return 21;
+    case 4096:
+        return 12;
+    }
+    return 0;
+}
+
+bool virtio_disk_is_eckd(void)
+{
+    const int block_size = virtio_get_block_size();
+
+    if (guessed_disk_nature) {
+        return (block_size  == 4096);
+    }
+    return (blk_cfg.geometry.heads == 15)
+        && (blk_cfg.geometry.sectors ==
+            virtio_eckd_sectors_for_block_size(block_size));
+}
+
+bool virtio_ipl_disk_is_valid(void)
+{
+    return virtio_disk_is_scsi() || virtio_disk_is_eckd();
+}
+
+int virtio_get_block_size(void)
+{
+    return blk_cfg.blk_size << blk_cfg.physical_block_exp;
+}
+
+uint8_t virtio_get_heads(void)
+{
+    return blk_cfg.geometry.heads;
+}
+
+uint8_t virtio_get_sectors(void)
+{
+    return blk_cfg.geometry.sectors;
+}
+
+uint64_t virtio_get_blocks(void)
+{
+    return blk_cfg.capacity /
+           (virtio_get_block_size() / VIRTIO_SECTOR_SIZE);
+}
+
+void virtio_setup_block(struct subchannel_id schid)
+{
+    struct vq_info_block info;
+    struct vq_config_block config = {};
+
+    blk_cfg.blk_size = 0; /* mark "illegal" - setup started... */
+    guessed_disk_nature = false;
+
+    virtio_reset(schid);
+
+    /*
+     * Skipping CCW_CMD_READ_FEAT. We're not doing anything fancy, and
+     * we'll just stop dead anyway if anything does not work like we
+     * expect it.
+     */
+
+    config.index = 0;
+    if (run_ccw(schid, CCW_CMD_READ_VQ_CONF, &config, sizeof(config))) {
+        virtio_panic("Could not get block device VQ configuration\n");
+    }
+    if (run_ccw(schid, CCW_CMD_READ_CONF, &blk_cfg, sizeof(blk_cfg))) {
+        virtio_panic("Could not get block device configuration\n");
+    }
+    vring_init(&block, config.num, ring_area,
+               KVM_S390_VIRTIO_RING_ALIGN);
+
+    info.queue = (unsigned long long) ring_area;
+    info.align = KVM_S390_VIRTIO_RING_ALIGN;
+    info.index = 0;
+    info.num = config.num;
+    block.schid = schid;
+
+    if (!run_ccw(schid, CCW_CMD_SET_VQ, &info, sizeof(info))) {
+        virtio_set_status(schid, VIRTIO_CONFIG_S_DRIVER_OK);
+    }
+
+    if (!virtio_ipl_disk_is_valid()) {
+        /* make sure all getters but blocksize return 0 for invalid IPL disk */
+        memset(&blk_cfg, 0, sizeof(blk_cfg));
+        virtio_assume_scsi();
+    }
+}
+
+bool virtio_is_blk(struct subchannel_id schid)
+{
+    int r;
+    struct senseid senseid = {};
+
+    /* run sense id command */
+    r = run_ccw(schid, CCW_CMD_SENSE_ID, &senseid, sizeof(senseid));
+    if (r) {
+        return false;
+    }
+    if ((senseid.cu_type != 0x3832) || (senseid.cu_model != VIRTIO_ID_BLOCK)) {
+        return false;
+    }
+
+    return true;
+}
+
+int enable_mss_facility(void)
+{
+    int ret;
+    struct chsc_area_sda *sda_area = (struct chsc_area_sda *) chsc_page;
+
+    memset(sda_area, 0, PAGE_SIZE);
+    sda_area->request.length = 0x0400;
+    sda_area->request.code = 0x0031;
+    sda_area->operation_code = 0x2;
+
+    ret = chsc(sda_area);
+    if ((ret == 0) && (sda_area->response.code == 0x0001)) {
+        return 0;
+    }
+    return -EIO;
+}