Current code seems to assume ring size is always decreased but this is not required by spec: what spec says is just that size can not exceed the maximum. Fix it up.
Signed-off-by: Michael S. Tsirkin <m...@redhat.com> --- include/hw/virtio/virtio.h | 1 + hw/s390x/virtio-ccw.c | 2 +- hw/virtio/virtio.c | 5 +++++ 3 files changed, 7 insertions(+), 1 deletion(-) diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index e5541c6..6523bac 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -228,6 +228,7 @@ void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr); hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n); void virtio_queue_set_num(VirtIODevice *vdev, int n, int num); int virtio_queue_get_num(VirtIODevice *vdev, int n); +int virtio_queue_get_max_num(VirtIODevice *vdev, int n); int virtio_get_num_queues(VirtIODevice *vdev); void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc, hwaddr avail, hwaddr used); diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c index 0765068..63c4637 100644 --- a/hw/s390x/virtio-ccw.c +++ b/hw/s390x/virtio-ccw.c @@ -149,7 +149,7 @@ static int virtio_ccw_set_vqs(SubchDev *sch, VqInfoBlock *info, } else { if (info) { /* virtio-1 allows changing the ring size. */ - if (virtio_queue_get_num(vdev, index) < num) { + if (virtio_queue_get_max_num(vdev, index) < num) { /* Fail if we exceed the maximum number. */ return -EINVAL; } diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 34065c7..e52fd8e 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -1256,6 +1256,11 @@ int virtio_queue_get_num(VirtIODevice *vdev, int n) return vdev->vq[n].vring.num; } +int virtio_queue_get_max_num(VirtIODevice *vdev, int n) +{ + return vdev->vq[n].vring.num_default; +} + int virtio_get_num_queues(VirtIODevice *vdev) { int i; -- MST