[PATCH] libxl: Add suppress-vmdesc to QEMU -machine pc options

[Jason Andryuk <jandryuk@xxxxxxxxx>]

The device model state saved by QMP xen-save-devices-state doesn't
include the vmdesc json.  When restoring an HVM, xen-load-devices-state
always triggers "Expected vmdescription section, but got 0".  This is
not a problem when restore comes from a file.  However, when QEMU runs
in a linux stubdom and comes over a console, EOF is not received.  This
causes a delay restoring - though it does restore.

Setting suppress-vmdesc skips looking for the vmdesc during restore and
avoids the wait.

This is a libxl change for the non-xenfv case to match the xenfv change
made in qemu

Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx>
---

Should this also add suppress-vmdesc to xenfv for backwards
compatibility?  In that case, the change in QEMU is redundent.  Since
this only really matters for the stubdom case, it could be conditioned
on that.

 tools/libs/light/libxl_dm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/libs/light/libxl_dm.c b/tools/libs/light/libxl_dm.c
index d1ff35dda3..7d735ffcd9 100644
--- a/tools/libs/light/libxl_dm.c
+++ b/tools/libs/light/libxl_dm.c
@@ -1778,7 +1778,7 @@ static int libxl__build_device_model_args_new(libxl__gc 
*gc,
             /* Switching here to the machine "pc" which does not add
              * the xen-platform device instead of the default "xenfv" machine.
              */
-            machinearg = libxl__strdup(gc, "pc,accel=xen");
+            machinearg = libxl__strdup(gc, "pc,accel=xen,suppress-vmdesc=on");
         } else {
             machinearg = libxl__strdup(gc, "xenfv");
         }
-- 
2.26.2