libxl: consider also qemu in stubdomain in libxl__dm_active check

Since qemu-xen can now run in stubdomain too, handle this case when
checking it's state too.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Jason Andryuk <jandryuk@gmail.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

tools/libxl/libxl_dm.c

@@ -3734,12 +3734,18 @@ out:
 
 int libxl__dm_active(libxl__gc *gc, uint32_t domid)
 {
-    char *pid, *path;
+    char *pid, *dm_domid, *path;
 
     path = GCSPRINTF("/local/domain/%d/image/device-model-pid", domid);
     pid = libxl__xs_read(gc, XBT_NULL, path);
 
-    return pid != NULL;
+    if (pid)
+        return true;
+
+    path = GCSPRINTF("/local/domain/%d/image/device-model-domid", domid);
+    dm_domid = libxl__xs_read(gc, XBT_NULL, path);
+
+    return dm_domid != NULL;
 }
 
 int libxl__dm_check_start(libxl__gc *gc, libxl_domain_config *d_config,