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>
This commit is contained in:
Cornelia Huck 2015-09-11 15:16:42 +02:00 committed by Michael S. Tsirkin
parent 46c5d0823d
commit 79cd0c80f8
1 changed files with 10 additions and 3 deletions

View File

@ -307,11 +307,18 @@ static int virtio_ccw_set_vqs(SubchDev *sch, VqInfoBlock *info,
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 */