Subject: libxl: No emulated disk driver for xvdX disk
From: Anthony PERARD anthony.perard@citrix.com Wed Oct 14 12:05:17 2015 +0100
Date: Thu Oct 22 16:10:31 2015 +0100:
Git: c0c099d157cc5bc942afef766cf141628a6380a1

When a guest configuration list xvdX for its disks, there is no need to
provide an emulated driver for the same target.

Such configuration can work with the OVMF firmware, as it supports PV
disk.

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

Index: xen-4.6.0-testing/tools/libxl/libxl_dm.c
===================================================================
--- xen-4.6.0-testing.orig/tools/libxl/libxl_dm.c
+++ xen-4.6.0-testing/tools/libxl/libxl_dm.c
@@ -1152,6 +1152,12 @@ static int libxl__build_device_model_arg
                     drive = libxl__sprintf
                         (gc, "file=%s,if=scsi,bus=0,unit=%d,format=%s,cache=writeback",
                          pdev_path, disk, format);
+                else if (strncmp(disks[i].vdev, "xvd", 3) == 0)
+                    /*
+                     * Do not add any emulated disk when PV disk are
+                     * explicitly asked for.
+                     */
+                    continue;
                 else if (disk < 6 && b_info->u.hvm.hdtype == LIBXL_HDTYPE_AHCI) {
                     flexarray_vappend(dm_args, "-drive",
                         GCSPRINTF("file=%s,if=none,id=ahcidisk-%d,format=%s,cache=writeback",