virtio-balloon: Unregister savevm section on device unplug

Migrating after unplugging a virtio-balloon device resulted in an error
message on the destination:

Unknown savevm section or instance '0000:00:04.0/virtio-balloon' 0
load of migration failed

Fix this by unregistering the section on device unplug.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c
index 0ce0049..072a88a 100644 (file)
--- a/hw/virtio-balloon.c
+++ b/hw/virtio-balloon.c
@@ -45,6 +45,7 @@ typedef struct VirtIOBalloon
     size_t stats_vq_offset;
     MonitorCompletion *stats_callback;
     void *stats_opaque_callback_data;
+    DeviceState *qdev;
 } VirtIOBalloon;
 
 static VirtIOBalloon *to_virtio_balloon(VirtIODevice *vdev)
@@ -292,6 +293,7 @@ VirtIODevice *virtio_balloon_init(DeviceState *dev)
 
     reset_stats(s);
 
+    s->qdev = dev;
     register_savevm(dev, "virtio-balloon", -1, 1,
                     virtio_balloon_save, virtio_balloon_load, s);
 
@@ -300,5 +302,7 @@ VirtIODevice *virtio_balloon_init(DeviceState *dev)
 
 void virtio_balloon_exit(VirtIODevice *vdev)
 {
+    VirtIOBalloon *s = DO_UPCAST(VirtIOBalloon, vdev, vdev);
+    unregister_savevm(s->qdev, "virtio-balloon", s);
     virtio_cleanup(vdev);
 }