virtio-ccw: support ring size changes
Wire up changing the ring size for virtio-1 devices.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index d36373e..85e2a5d 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -307,11 +307,18 @@
if (!desc) {
virtio_queue_set_vector(vdev, index, VIRTIO_NO_VECTOR);
} else {
- /* Fail if we don't have a big enough queue. */
- /* TODO: Add interface to handle vring.num changing */
- if (virtio_queue_get_num(vdev, index) > num) {
+ if (info) {
+ /* virtio-1 allows changing the ring size. */
+ if (virtio_queue_get_num(vdev, index) < num) {
+ /* Fail if we exceed the maximum number. */
+ return -EINVAL;
+ }
+ virtio_queue_set_num(vdev, index, num);
+ } else if (virtio_queue_get_num(vdev, index) > num) {
+ /* Fail if we don't have a big enough queue. */
return -EINVAL;
}
+ /* We ignore possible increased num for legacy for compatibility. */
virtio_queue_set_vector(vdev, index, index);
}
/* tell notify handler in case of config change */
