libxl_dm: Replace deprecated -drive if=scsi

.. by -drive if=none,.. -device scsi-disk,...

The use of if=scsi in QEMU is deprecated and has been removed in 2.12 by
1454509726 scsi: Remove automatic creation of SCSI controllers with -drive if=scsi

It used to create a SCSI controller, now we have to explicitly create
it in libxl. This is done ahead of disks creation in order to try to
keep the controller on the PCI slot as it used to be.

The chosen "id" for drive is the same that QEMU used to create.

This patch also take the opportunity to remove the comments in
qemu_disk_scsi_drive_string() which had a typo and is now out of date.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index a3cddce8b7b224a66b15a17bf681190b157720fc..7bbfa40a5aa7942e522f00f3fc4b6a149967d9b4 100644 (file)
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -808,51 +808,35 @@ enum {
 static char *qemu_disk_scsi_drive_string(libxl__gc *gc, const char *target_path,
                                          int unit, const char *format,
                                          const libxl_device_disk *disk,
-                                         int colo_mode)
+                                         int colo_mode, const char **id_ptr)
 {
     char *drive = NULL;
     const char *exportname = disk->colo_export;
     const char *active_disk = disk->active_disk;
     const char *hidden_disk = disk->hidden_disk;
+    const char *id;
 
     switch (colo_mode) {
     case LIBXL__COLO_NONE:
-        drive = libxl__sprintf
-            (gc, "file=%s,if=scsi,bus=0,unit=%d,format=%s,cache=writeback",
-             target_path, unit, format);
+        id = GCSPRINTF("scsi0-hd%d", unit);
+        drive = GCSPRINTF("file=%s,if=none,id=%s,format=%s,cache=writeback",
+                          target_path, id, format);
         break;
     case LIBXL__COLO_PRIMARY:
-        /*
-         * primary:
-         *  -dirve if=scsi,bus=0,unit=x,cache=writeback,driver=quorum,\
-         *  id=exportname,\
-         *  children.0.file.filename=target_path,\
-         *  children.0.driver=format,\
-         *  read-pattern=fifo,\
-         *  vote-threshold=1
-         */
+        id = exportname;
         drive = GCSPRINTF(
-            "if=scsi,bus=0,unit=%d,cache=writeback,driver=quorum,"
+            "if=none,cache=writeback,driver=quorum,"
             "id=%s,"
             "children.0.file.filename=%s,"
             "children.0.driver=%s,"
             "read-pattern=fifo,"
             "vote-threshold=1",
-            unit, exportname, target_path, format);
+            id, target_path, format);
         break;
     case LIBXL__COLO_SECONDARY:
-        /*
-         * secondary:
-         *  -drive if=scsi,bus=0,unit=x,cache=writeback,driver=replication,\
-         *  mode=secondary,\
-         *  file.driver=qcow2,\
-         *  file.file.filename=active_disk,\
-         *  file.backing.driver=qcow2,\
-         *  file.backing.file.filename=hidden_disk,\
-         *  file.backing.backing=exportname,
-         */
+        id = "top-colo";
         drive = GCSPRINTF(
-            "if=scsi,id=top-colo,bus=0,unit=%d,cache=writeback,"
+            "if=none,id=%s,cache=writeback,"
             "driver=replication,"
             "mode=secondary,"
             "top-id=top-colo,"
@@ -861,12 +845,14 @@ static char *qemu_disk_scsi_drive_string(libxl__gc *gc, const char *target_path,
             "file.backing.driver=qcow2,"
             "file.backing.file.filename=%s,"
             "file.backing.backing=%s",
-            unit, active_disk, hidden_disk, exportname);
+            id, active_disk, hidden_disk, exportname);
         break;
     default:
         abort();
     }
 
+    *id_ptr = id;
+
     return drive;
 }
 
@@ -1104,6 +1090,19 @@ static int libxl__build_device_model_args_new(libxl__gc *gc,
         if (b_info->cmdline)
             flexarray_vappend(dm_args, "-append", b_info->cmdline, NULL);
 
+        /* Find out early if one of the disk is on the scsi bus and add a scsi
+         * controller. This is done ahead to keep the same behavior as previous
+         * version of QEMU (have the controller on the same PCI slot). */
+        for (i = 0; i < num_disks; i++) {
+            if (disks[i].is_cdrom) {
+                continue;
+            }
+            if (strncmp(disks[i].vdev, "sd", 2) == 0) {
+                flexarray_vappend(dm_args, "-device", "lsi53c895a", NULL);
+                break;
+            }
+        }
+
         if (b_info->u.hvm.serial || b_info->u.hvm.serial_list) {
             if ( b_info->u.hvm.serial && b_info->u.hvm.serial_list )
             {
@@ -1586,6 +1585,7 @@ static int libxl__build_device_model_args_new(libxl__gc *gc,
                 }
 
                 if (strncmp(disks[i].vdev, "sd", 2) == 0) {
+                    const char *drive_id;
                     if (colo_mode == LIBXL__COLO_SECONDARY) {
                         drive = libxl__sprintf
                             (gc, "if=none,driver=%s,file=%s,id=%s",
@@ -1597,7 +1597,14 @@ static int libxl__build_device_model_args_new(libxl__gc *gc,
                     drive = qemu_disk_scsi_drive_string(gc, target_path, disk,
                                                         format,
                                                         &disks[i],
-                                                        colo_mode);
+                                                        colo_mode,
+                                                        &drive_id),
+                    flexarray_vappend(dm_args,
+                        "-drive", drive,
+                        "-device", GCSPRINTF("scsi-disk,drive=%s,scsi-id=%d",
+                                             drive_id, disk),
+                        NULL);
+                    continue;
                 } else if (disk < 6 && b_info->u.hvm.hdtype == LIBXL_HDTYPE_AHCI) {
                     if (!disks[i].readwrite) {
                         LOGD(ERROR, guest_domid,