qemu: init all queues to NO_VECTOR value

initialize vectors for all vqs to VIRTIO_NO_VECTOR rather than 0 which
is a valid vector. This fixes migration which happened before driver
was loaded.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reported-by: NAmit Shah <amit.shah@redhat.com>
Tested-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/virtio.c

@@ -694,6 +694,7 @@ VirtIODevice *virtio_common_init(const char *name, uint16_t device_id,
                                  size_t config_size, size_t struct_size)
 {
     VirtIODevice *vdev;
+    int i;
 
     vdev = qemu_mallocz(struct_size);
 
@@ -703,6 +704,8 @@ VirtIODevice *virtio_common_init(const char *name, uint16_t device_id,
     vdev->queue_sel = 0;
     vdev->config_vector = VIRTIO_NO_VECTOR;
     vdev->vq = qemu_mallocz(sizeof(VirtQueue) * VIRTIO_PCI_QUEUE_MAX);
+    for(i = 0; i < VIRTIO_PCI_QUEUE_MAX; i++)
+        vdev->vq[i].vector = VIRTIO_NO_VECTOR;
 
     vdev->name = name;
     vdev->config_len = config_size;