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* [Qemu-devel] [PATCH] virtio: allow mapping up to max queue size
@ 2014-05-12  9:08 Michael S. Tsirkin
  2014-05-13  8:57 ` Dr. David Alan Gilbert
  2014-05-13 12:03 ` Stefan Hajnoczi
  0 siblings, 2 replies; 3+ messages in thread
From: Michael S. Tsirkin @ 2014-05-12  9:08 UTC (permalink / raw)
  To: qemu-devel
  Cc: peter.maydell, stefanha, Dr. David Alan Gilbert, Anthony Liguori,
	qemu-stable

It's a loop from i < num_sg  and the array is VIRTQUEUE_MAX_SIZE - so
it's OK if the value read is VIRTQUEUE_MAX_SIZE.

Not a big problem in practice as people don't use
such big queues, but it's inelegant.

Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/virtio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 7f4e7ec..3557c17 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -430,7 +430,7 @@ void virtqueue_map_sg(struct iovec *sg, hwaddr *addr,
     unsigned int i;
     hwaddr len;
 
-    if (num_sg >= VIRTQUEUE_MAX_SIZE) {
+    if (num_sg > VIRTQUEUE_MAX_SIZE) {
         error_report("virtio: map attempt out of bounds: %zd > %d",
                      num_sg, VIRTQUEUE_MAX_SIZE);
         exit(1);
-- 
MST

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [Qemu-devel] [PATCH] virtio: allow mapping up to max queue size
  2014-05-12  9:08 [Qemu-devel] [PATCH] virtio: allow mapping up to max queue size Michael S. Tsirkin
@ 2014-05-13  8:57 ` Dr. David Alan Gilbert
  2014-05-13 12:03 ` Stefan Hajnoczi
  1 sibling, 0 replies; 3+ messages in thread
From: Dr. David Alan Gilbert @ 2014-05-13  8:57 UTC (permalink / raw)
  To: Michael S. Tsirkin
  Cc: peter.maydell, qemu-stable, qemu-devel, stefanha, Anthony Liguori

* Michael S. Tsirkin (mst@redhat.com) wrote:
> It's a loop from i < num_sg  and the array is VIRTQUEUE_MAX_SIZE - so
> it's OK if the value read is VIRTQUEUE_MAX_SIZE.
> 
> Not a big problem in practice as people don't use
> such big queues, but it's inelegant.
> 
> Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  hw/virtio/virtio.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 7f4e7ec..3557c17 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -430,7 +430,7 @@ void virtqueue_map_sg(struct iovec *sg, hwaddr *addr,
>      unsigned int i;
>      hwaddr len;
>  
> -    if (num_sg >= VIRTQUEUE_MAX_SIZE) {
> +    if (num_sg > VIRTQUEUE_MAX_SIZE) {
>          error_report("virtio: map attempt out of bounds: %zd > %d",
>                       num_sg, VIRTQUEUE_MAX_SIZE);
>          exit(1);
> -- 
> MST
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [Qemu-devel] [PATCH] virtio: allow mapping up to max queue size
  2014-05-12  9:08 [Qemu-devel] [PATCH] virtio: allow mapping up to max queue size Michael S. Tsirkin
  2014-05-13  8:57 ` Dr. David Alan Gilbert
@ 2014-05-13 12:03 ` Stefan Hajnoczi
  1 sibling, 0 replies; 3+ messages in thread
From: Stefan Hajnoczi @ 2014-05-13 12:03 UTC (permalink / raw)
  To: Michael S. Tsirkin
  Cc: peter.maydell, qemu-stable, qemu-devel, Anthony Liguori,
	Dr. David Alan Gilbert

On Mon, May 12, 2014 at 12:08:21PM +0300, Michael S. Tsirkin wrote:
> It's a loop from i < num_sg  and the array is VIRTQUEUE_MAX_SIZE - so
> it's OK if the value read is VIRTQUEUE_MAX_SIZE.
> 
> Not a big problem in practice as people don't use
> such big queues, but it's inelegant.
> 
> Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  hw/virtio/virtio.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2014-05-13 12:03 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2014-05-12  9:08 [Qemu-devel] [PATCH] virtio: allow mapping up to max queue size Michael S. Tsirkin
2014-05-13  8:57 ` Dr. David Alan Gilbert
2014-05-13 12:03 ` Stefan Hajnoczi

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