Re: [Qemu-devel] [RFC 25/29] vhu: enable = false on get_vring_base

[Michael S. Tsirkin]

On Wed, Jun 28, 2017 at 08:00:43PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
> 
> When we receive a GET_VRING_BASE message set enable = false
> to stop any new received packets modifying the ring.
> 
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>

I think I already reviewed a similar patch.
Spec says:
Client must only process each ring when it is started.

IMHO the real fix is to fix client to check the started
flag before processing the ring.

> ---
>  contrib/libvhost-user/libvhost-user.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/contrib/libvhost-user/libvhost-user.c 
> b/contrib/libvhost-user/libvhost-user.c
> index ceddeac74f..d37052b7b0 100644
> --- a/contrib/libvhost-user/libvhost-user.c
> +++ b/contrib/libvhost-user/libvhost-user.c
> @@ -652,6 +652,7 @@ vu_get_vring_base_exec(VuDev *dev, VhostUserMsg *vmsg)
>      vmsg->size = sizeof(vmsg->payload.state);
>  
>      dev->vq[index].started = false;
> +    dev->vq[index].enable = false;
>      if (dev->iface->queue_set_started) {
>          dev->iface->queue_set_started(dev, index, false);
>      }
> -- 
> 2.13.0