Re: [Qemu-devel] [PATCH] virtio-ccw: fix ring sizing

[Cornelia Huck]

On Thu, 12 Jan 2017 23:26:22 +0200
"Michael S. Tsirkin"  wrote:

> 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 
> ---
>  include/hw/virtio/virtio.h | 1 +
>  hw/s390x/virtio-ccw.c  | 2 +-
>  hw/virtio/virtio.c | 5 +
>  3 files changed, 7 insertions(+), 1 deletion(-)

Yes, makes sense. Queued to s390-next.

[Qemu-devel] [PATCH] virtio-ccw: fix ring sizing

[Michael S. Tsirkin]

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 
---
 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