libxl: No emulated disk driver for xvdX disk

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>

diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
index e33d492e53e83fa9c098c758fa12832da13b76a4..9c9eaa3b9c92e1ebf8fc541cb62eefab03e626d8 100644 (file)
--- a/tools/libxl/libxl_dm.c
+++ b/tools/libxl/libxl_dm.c
@@ -1189,6 +1189,12 @@ static int libxl__build_device_model_args_new(libxl__gc *gc,
                     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",