Re: [Qemu-devel] virtIO question

[Stefan Hajnoczi]

On Mon, Nov 14, 2016 at 08:36:39PM +0800, address@hidden wrote:
> I have a question about qemu.is it a bug in qemu version 1.2?
> in qemu version 1.2 ,it set avail event by the code :
>  if (vq->vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
>         vring_avail_event(vq, vring_avail_idx(vq));
>         }
>  and in version 2.7 the code is
>  if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
>         vring_set_avail_event(vq, vq->last_avail_idx);
>     }
> 
> a big difference of this is the value.vring_avail_idx(vq)is the latest value 
> of VRingAvail.idx,and vq->last_avail_idx is not, I think it really different 
> with the two different values,and I think the later is right,is it??

qemu.git/master has both vring_set_avail_event(vq, vring_avail_idx(vq))
and vring_set_avail_event(vq, vq->last_avail_idx) so I'm not sure what
you are referring to.

Please use git-blame(1) and git-log(1) to investigate changes to the
code yourself.

Stefan

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