virtio_balloon: enable VQs early on restore

virtio spec requires drivers to set DRIVER_OK before using VQs.
This is set automatically after resume returns, virtio balloon
violated this rule by adding bufs, which causes the VQ to be used
directly within restore.

To fix, call virtio_device_ready before using VQ.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 25ebe8eecdb7397be646623775bd42c538ba0100..f4a28af4865ef450d62821d24f1ddf0f8239cfe5 100644 (file)
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -538,6 +538,8 @@ static int virtballoon_restore(struct virtio_device *vdev)
        if (ret)
                return ret;
 
+       virtio_device_ready(vdev);
+
        fill_balloon(vb, towards_target(vb));
        update_balloon_size(vb);
        return 0;