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Date: Mon, 27 Feb 2017 16:39:19 +0100
From: Cornelia Huck <cornelia.huck@de.ibm.com>
In-Reply-To: <20170223085130.19954-1-pbonzini@redhat.com>
References: <20170223085130.19954-1-pbonzini@redhat.com>
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Message-Id: <20170227163919.7276be2b.cornelia.huck@de.ibm.com>
Subject: Re: [Qemu-devel] [PATCH] virtio: check for vring setup in
 virtio_queue_empty
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org, alex.williamson@redhat.com, lersek@redhat.com, kraxel@redhat.com, mst@redhat.com

On Thu, 23 Feb 2017 09:51:30 +0100
Paolo Bonzini <pbonzini@redhat.com> wrote:

> If the vring has not been set up, there is nothing in the virtqueue.
> virtio_queue_host_notifier_aio_poll calls virtio_queue_empty even in
> this case; we have to filter it out just like virtio_queue_notify_aio_vq.
> 
> Reported-by: Gerd Hoffmann <kraxel@redhat.com>
> Tested-by: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@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 23483c7..e487e36 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -2291,7 +2291,7 @@ static bool virtio_queue_host_notifier_aio_poll(void *opaque)
>      VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
>      bool progress;
> 
> -    if (virtio_queue_empty(vq)) {
> +    if (!vq->vring.desc || virtio_queue_empty(vq)) {
>          return false;
>      }
> 

Tested-by: Cornelia Huck <cornelia.huck@de.ibm.com>

...although it is not sufficient...