diff --git a/hw/virtio.c b/hw/virtio.c
index f40a8c5..6227642 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -788,6 +788,8 @@ void virtio_save(VirtIODevice *vdev, QEMUFile *f)
         if (vdev->vq[i].vring.num == 0)
             break;
 
+        assert(!vdev->vq[i].inuse);
+
         qemu_put_be32(f, vdev->vq[i].vring.num);
         qemu_put_be64(f, vdev->vq[i].pa);
         qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);