1 files changed, 485 insertions, 0 deletions

diff --git a/grub-core/disk/xen/xendisk.c b/grub-core/disk/xen/xendisk.c
new file mode 100644
index 0000000..d6612ee
--- /dev/null
+++ b/grub-core/disk/xen/xendisk.c
@@ -0,0 +1,485 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2013  Free Software Foundation, Inc.
+ *
+ *  GRUB 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 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/disk.h>
+#include <grub/dl.h>
+#include <grub/mm.h>
+#include <grub/types.h>
+#include <grub/misc.h>
+#include <grub/err.h>
+#include <grub/term.h>
+#include <grub/i18n.h>
+#include <grub/xen.h>
+#include <grub/time.h>
+#include <xen/io/blkif.h>
+
+struct virtdisk
+{
+  int handle;
+  char *fullname;
+  char *backend_dir;
+  char *frontend_dir;
+  struct blkif_sring *shared_page;
+  struct blkif_front_ring ring;
+  grub_xen_grant_t grant;
+  grub_xen_evtchn_t evtchn;
+  void *dma_page;
+  grub_xen_grant_t dma_grant;
+  struct virtdisk *compat_next;
+};
+
+#define xen_wmb() mb()
+#define xen_mb() mb()
+
+static struct virtdisk *virtdisks;
+static grub_size_t vdiskcnt;
+struct virtdisk *compat_head;
+
+static int
+grub_virtdisk_iterate (grub_disk_dev_iterate_hook_t hook, void *hook_data,
+		       grub_disk_pull_t pull)
+{
+  grub_size_t i;
+
+  if (pull != GRUB_DISK_PULL_NONE)
+    return 0;
+
+  for (i = 0; i < vdiskcnt; i++)
+    if (hook (virtdisks[i].fullname, hook_data))
+      return 1;
+  return 0;
+}
+
+static grub_err_t
+grub_virtdisk_open (const char *name, grub_disk_t disk)
+{
+  int i;
+  grub_uint32_t secsize;
+  char fdir[200];
+  char *buf;
+  int num = -1;
+  struct virtdisk *vd;
+
+  /* For compatibility with pv-grub legacy menu.lst accept hdX as disk name */
+  if (name[0] == 'h' && name[1] == 'd' && name[2])
+    {
+      num = grub_strtoul (name + 2, 0, 10);
+      if (grub_errno)
+	{
+	  grub_errno = 0;
+	  num = -1;
+	}
+    }
+  for (i = 0, vd = compat_head; vd; vd = vd->compat_next, i++)
+    if (i == num || grub_strcmp (name, vd->fullname) == 0)
+      break;
+  if (!vd)
+    return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "not a virtdisk");
+  disk->data = vd;
+  disk->id = vd - virtdisks;
+
+  grub_snprintf (fdir, sizeof (fdir), "%s/sectors", vd->backend_dir);
+  buf = grub_xenstore_get_file (fdir, NULL);
+  if (!buf)
+    return grub_errno;
+  disk->total_sectors = grub_strtoull (buf, 0, 10);
+  if (grub_errno)
+    return grub_errno;
+
+  grub_snprintf (fdir, sizeof (fdir), "%s/sector-size", vd->backend_dir);
+  buf = grub_xenstore_get_file (fdir, NULL);
+  if (!buf)
+    return grub_errno;
+  secsize = grub_strtoull (buf, 0, 10);
+  if (grub_errno)
+    return grub_errno;
+
+  if ((secsize & (secsize - 1)) || !secsize || secsize < 512
+      || secsize > GRUB_XEN_PAGE_SIZE)
+    return grub_error (GRUB_ERR_IO, "unsupported sector size %d", secsize);
+
+  for (disk->log_sector_size = 0;
+       (1U << disk->log_sector_size) < secsize; disk->log_sector_size++);
+
+  disk->total_sectors >>= disk->log_sector_size - 9;
+
+  return GRUB_ERR_NONE;
+}
+
+static void
+grub_virtdisk_close (grub_disk_t disk __attribute__ ((unused)))
+{
+}
+
+static grub_err_t
+grub_virtdisk_read (grub_disk_t disk, grub_disk_addr_t sector,
+		    grub_size_t size, char *buf)
+{
+  struct virtdisk *data = disk->data;
+
+  while (size)
+    {
+      grub_size_t cur;
+      struct blkif_request *req;
+      struct blkif_response *resp;
+      int sta = 0;
+      struct evtchn_send send;
+      cur = size;
+      if (cur > (unsigned) (GRUB_XEN_PAGE_SIZE >> disk->log_sector_size))
+	cur = GRUB_XEN_PAGE_SIZE >> disk->log_sector_size;
+      while (RING_FULL (&data->ring))
+	grub_xen_sched_op (SCHEDOP_yield, 0);
+      req = RING_GET_REQUEST (&data->ring, data->ring.req_prod_pvt);
+      req->operation = BLKIF_OP_READ;
+      req->nr_segments = 1;
+      req->handle = data->handle;
+      req->id = 0;
+      req->sector_number = sector << (disk->log_sector_size - 9);
+      req->seg[0].gref = data->dma_grant;
+      req->seg[0].first_sect = 0;
+      req->seg[0].last_sect = (cur << (disk->log_sector_size - 9)) - 1;
+      data->ring.req_prod_pvt++;
+      RING_PUSH_REQUESTS (&data->ring);
+      mb ();
+      send.port = data->evtchn;
+      grub_xen_event_channel_op (EVTCHNOP_send, &send);
+
+      while (!RING_HAS_UNCONSUMED_RESPONSES (&data->ring))
+	{
+	  grub_xen_sched_op (SCHEDOP_yield, 0);
+	  mb ();
+	}
+      while (1)
+	{
+	  int wtd;
+	  RING_FINAL_CHECK_FOR_RESPONSES (&data->ring, wtd);
+	  if (!wtd)
+	    break;
+	  resp = RING_GET_RESPONSE (&data->ring, data->ring.rsp_cons);
+	  data->ring.rsp_cons++;
+	  if (resp->status)
+	    sta = resp->status;
+	}
+      if (sta)
+	return grub_error (GRUB_ERR_IO, "read failed");
+      grub_memcpy (buf, data->dma_page, cur << disk->log_sector_size);
+      size -= cur;
+      sector += cur;
+      buf += cur << disk->log_sector_size;
+    }
+  return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_virtdisk_write (grub_disk_t disk, grub_disk_addr_t sector,
+		     grub_size_t size, const char *buf)
+{
+  struct virtdisk *data = disk->data;
+
+  while (size)
+    {
+      grub_size_t cur;
+      struct blkif_request *req;
+      struct blkif_response *resp;
+      int sta = 0;
+      struct evtchn_send send;
+      cur = size;
+      if (cur > (unsigned) (GRUB_XEN_PAGE_SIZE >> disk->log_sector_size))
+	cur = GRUB_XEN_PAGE_SIZE >> disk->log_sector_size;
+
+      grub_memcpy (data->dma_page, buf, cur << disk->log_sector_size);
+
+      while (RING_FULL (&data->ring))
+	grub_xen_sched_op (SCHEDOP_yield, 0);
+      req = RING_GET_REQUEST (&data->ring, data->ring.req_prod_pvt);
+      req->operation = BLKIF_OP_WRITE;
+      req->nr_segments = 1;
+      req->handle = data->handle;
+      req->id = 0;
+      req->sector_number = sector << (disk->log_sector_size - 9);
+      req->seg[0].gref = data->dma_grant;
+      req->seg[0].first_sect = 0;
+      req->seg[0].last_sect = (cur << (disk->log_sector_size - 9)) - 1;
+      data->ring.req_prod_pvt++;
+      RING_PUSH_REQUESTS (&data->ring);
+      mb ();
+      send.port = data->evtchn;
+      grub_xen_event_channel_op (EVTCHNOP_send, &send);
+
+      while (!RING_HAS_UNCONSUMED_RESPONSES (&data->ring))
+	{
+	  grub_xen_sched_op (SCHEDOP_yield, 0);
+	  mb ();
+	}
+      while (1)
+	{
+	  int wtd;
+	  RING_FINAL_CHECK_FOR_RESPONSES (&data->ring, wtd);
+	  if (!wtd)
+	    break;
+	  resp = RING_GET_RESPONSE (&data->ring, data->ring.rsp_cons);
+	  data->ring.rsp_cons++;
+	  if (resp->status)
+	    sta = resp->status;
+	}
+      if (sta)
+	return grub_error (GRUB_ERR_IO, "write failed");
+      size -= cur;
+      sector += cur;
+      buf += cur << disk->log_sector_size;
+    }
+  return GRUB_ERR_NONE;
+}
+
+static struct grub_disk_dev grub_virtdisk_dev = {
+  .name = "xen",
+  .id = GRUB_DISK_DEVICE_XEN,
+  .disk_iterate = grub_virtdisk_iterate,
+  .disk_open = grub_virtdisk_open,
+  .disk_close = grub_virtdisk_close,
+  .disk_read = grub_virtdisk_read,
+  .disk_write = grub_virtdisk_write,
+  .next = 0
+};
+
+static int
+count (const char *dir __attribute__ ((unused)), void *data)
+{
+  grub_size_t *ctr = data;
+  (*ctr)++;
+
+  return 0;
+}
+
+static int
+fill (const char *dir, void *data)
+{
+  grub_size_t *ctr = data;
+  domid_t dom;
+  /* "dir" is just a number, at most 19 characters. */
+  char fdir[200];
+  char num[20];
+  grub_err_t err;
+  void *buf;
+  struct evtchn_alloc_unbound alloc_unbound;
+  struct virtdisk **prev = &compat_head, *vd = compat_head;
+
+  /* Shouldn't happen unles some hotplug happened.  */
+  if (vdiskcnt >= *ctr)
+    return 1;
+  virtdisks[vdiskcnt].handle = grub_strtoul (dir, 0, 10);
+  if (grub_errno)
+    {
+      grub_errno = 0;
+      return 0;
+    }
+  virtdisks[vdiskcnt].fullname = 0;
+  virtdisks[vdiskcnt].backend_dir = 0;
+
+  grub_snprintf (fdir, sizeof (fdir), "device/vbd/%s/backend", dir);
+  virtdisks[vdiskcnt].backend_dir = grub_xenstore_get_file (fdir, NULL);
+  if (!virtdisks[vdiskcnt].backend_dir)
+    goto out_fail_1;
+
+  grub_snprintf (fdir, sizeof (fdir), "%s/dev",
+		 virtdisks[vdiskcnt].backend_dir);
+  buf = grub_xenstore_get_file (fdir, NULL);
+  if (!buf)
+    {
+      grub_errno = 0;
+      virtdisks[vdiskcnt].fullname = grub_xasprintf ("xenid/%s", dir);
+    }
+  else
+    {
+      virtdisks[vdiskcnt].fullname = grub_xasprintf ("xen/%s", (char *) buf);
+      grub_free (buf);
+    }
+  if (!virtdisks[vdiskcnt].fullname)
+    goto out_fail_1;
+
+  grub_snprintf (fdir, sizeof (fdir), "device/vbd/%s/backend-id", dir);
+  buf = grub_xenstore_get_file (fdir, NULL);
+  if (!buf)
+    goto out_fail_1;
+
+  dom = grub_strtoul (buf, 0, 10);
+  grub_free (buf);
+  if (grub_errno)
+    goto out_fail_1;
+
+  virtdisks[vdiskcnt].shared_page =
+    grub_xen_alloc_shared_page (dom, &virtdisks[vdiskcnt].grant);
+  if (!virtdisks[vdiskcnt].shared_page)
+    goto out_fail_1;
+
+  virtdisks[vdiskcnt].dma_page =
+    grub_xen_alloc_shared_page (dom, &virtdisks[vdiskcnt].dma_grant);
+  if (!virtdisks[vdiskcnt].dma_page)
+    goto out_fail_2;
+
+  alloc_unbound.dom = DOMID_SELF;
+  alloc_unbound.remote_dom = dom;
+
+  grub_xen_event_channel_op (EVTCHNOP_alloc_unbound, &alloc_unbound);
+  virtdisks[vdiskcnt].evtchn = alloc_unbound.port;
+
+  SHARED_RING_INIT (virtdisks[vdiskcnt].shared_page);
+  FRONT_RING_INIT (&virtdisks[vdiskcnt].ring, virtdisks[vdiskcnt].shared_page,
+		   GRUB_XEN_PAGE_SIZE);
+
+  grub_snprintf (fdir, sizeof (fdir), "device/vbd/%s/ring-ref", dir);
+  grub_snprintf (num, sizeof (num), "%u", virtdisks[vdiskcnt].grant);
+  err = grub_xenstore_write_file (fdir, num, grub_strlen (num));
+  if (err)
+    goto out_fail_3;
+
+  grub_snprintf (fdir, sizeof (fdir), "device/vbd/%s/event-channel", dir);
+  grub_snprintf (num, sizeof (num), "%u", virtdisks[vdiskcnt].evtchn);
+  err = grub_xenstore_write_file (fdir, num, grub_strlen (num));
+  if (err)
+    goto out_fail_3;
+
+  grub_snprintf (fdir, sizeof (fdir), "device/vbd/%s/protocol", dir);
+  err = grub_xenstore_write_file (fdir, XEN_IO_PROTO_ABI_NATIVE,
+				  grub_strlen (XEN_IO_PROTO_ABI_NATIVE));
+  if (err)
+    goto out_fail_3;
+
+  struct gnttab_dump_table dt;
+  dt.dom = DOMID_SELF;
+  grub_xen_grant_table_op (GNTTABOP_dump_table, (void *) &dt, 1);
+
+  grub_snprintf (fdir, sizeof (fdir), "device/vbd/%s/state", dir);
+  err = grub_xenstore_write_file (fdir, "3", 1);
+  if (err)
+    goto out_fail_3;
+
+  while (1)
+    {
+      grub_snprintf (fdir, sizeof (fdir), "%s/state",
+		     virtdisks[vdiskcnt].backend_dir);
+      buf = grub_xenstore_get_file (fdir, NULL);
+      if (!buf)
+	goto out_fail_3;
+      if (grub_strcmp (buf, "2") != 0)
+	break;
+      grub_free (buf);
+      grub_xen_sched_op (SCHEDOP_yield, 0);
+    }
+  grub_dprintf ("xen", "state=%s\n", (char *) buf);
+  grub_free (buf);
+
+  grub_snprintf (fdir, sizeof (fdir), "device/vbd/%s", dir);
+
+  virtdisks[vdiskcnt].frontend_dir = grub_strdup (fdir);
+
+  /* For compatibility with pv-grub maintain linked list sorted by handle
+     value in increasing order. This allows mapping of (hdX) disk names
+     from legacy menu.lst */
+  while (vd)
+    {
+      if (vd->handle > virtdisks[vdiskcnt].handle)
+	break;
+      prev = &vd->compat_next;
+      vd = vd->compat_next;
+    }
+  virtdisks[vdiskcnt].compat_next = vd;
+  *prev = &virtdisks[vdiskcnt];
+
+  vdiskcnt++;
+  return 0;
+
+out_fail_3:
+  grub_xen_free_shared_page (virtdisks[vdiskcnt].dma_page);
+out_fail_2:
+  grub_xen_free_shared_page (virtdisks[vdiskcnt].shared_page);
+out_fail_1:
+  grub_free (virtdisks[vdiskcnt].backend_dir);
+  grub_free (virtdisks[vdiskcnt].fullname);
+
+  grub_errno = 0;
+  return 0;
+}
+
+void
+grub_xendisk_init (void)
+{
+  grub_size_t ctr = 0;
+  if (grub_xenstore_dir ("device/vbd", count, &ctr))
+    grub_errno = 0;
+
+  if (!ctr)
+    return;
+
+  virtdisks = grub_calloc (ctr, sizeof (virtdisks[0]));
+  if (!virtdisks)
+    return;
+  if (grub_xenstore_dir ("device/vbd", fill, &ctr))
+    grub_errno = 0;
+
+  grub_disk_dev_register (&grub_virtdisk_dev);
+}
+
+void
+grub_xendisk_fini (void)
+{
+  char fdir[200];
+  unsigned i;
+
+  for (i = 0; i < vdiskcnt; i++)
+    {
+      char *buf;
+      struct evtchn_close close_op = {.port = virtdisks[i].evtchn };
+
+      grub_snprintf (fdir, sizeof (fdir), "%s/state",
+		     virtdisks[i].frontend_dir);
+      grub_xenstore_write_file (fdir, "6", 1);
+
+      while (1)
+	{
+	  grub_snprintf (fdir, sizeof (fdir), "%s/state",
+			 virtdisks[i].backend_dir);
+	  buf = grub_xenstore_get_file (fdir, NULL);
+	  grub_dprintf ("xen", "state=%s\n", (char *) buf);
+
+	  if (!buf || grub_strcmp (buf, "6") == 0)
+	    break;
+	  grub_free (buf);
+	  grub_xen_sched_op (SCHEDOP_yield, 0);
+	}
+      grub_free (buf);
+
+      grub_snprintf (fdir, sizeof (fdir), "%s/ring-ref",
+		     virtdisks[i].frontend_dir);
+      grub_xenstore_write_file (fdir, NULL, 0);
+
+      grub_snprintf (fdir, sizeof (fdir), "%s/event-channel",
+		     virtdisks[i].frontend_dir);
+      grub_xenstore_write_file (fdir, NULL, 0);
+
+      grub_xen_free_shared_page (virtdisks[i].dma_page);
+      grub_xen_free_shared_page (virtdisks[i].shared_page);
+
+      grub_xen_event_channel_op (EVTCHNOP_close, &close_op);
+
+      /* Prepare for handoff.  */
+      grub_snprintf (fdir, sizeof (fdir), "%s/state",
+		     virtdisks[i].frontend_dir);
+      grub_xenstore_write_file (fdir, "1", 1);
+    }
+}