[RFC 02/27] vhost: fix invalid call FD handling

[Xia, Chenbo]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin at redhat.com>
> Sent: Friday, March 31, 2023 11:43 PM
> To: dev at dpdk.org; david.marchand at redhat.com; Xia, Chenbo
> <chenbo.xia at intel.com>; mkp at redhat.com; fbl at redhat.com;
> jasowang at redhat.com; Liang, Cunming <cunming.liang at intel.com>; Xie, Yongji
> <xieyongji at bytedance.com>; echaudro at redhat.com; eperezma at redhat.com;
> amorenoz at redhat.com
> Cc: Maxime Coquelin <maxime.coquelin at redhat.com>; stable at dpdk.org
> Subject: [RFC 02/27] vhost: fix invalid call FD handling
> 
> This patch fixes cases where IRQ injection is tried while
> the call FD is not valid, which should not happen.
> 
> Fixes: b1cce26af1dc ("vhost: add notification for packed ring")
> Fixes: e37ff954405a ("vhost: support virtqueue interrupt/notification
> suppression")
> Cc: stable at dpdk.org
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---
>  lib/vhost/vhost.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
> index 8554ab4002..40863f7bfd 100644
> --- a/lib/vhost/vhost.h
> +++ b/lib/vhost/vhost.h
> @@ -902,9 +902,9 @@ vhost_vring_call_split(struct virtio_net *dev, struct
> vhost_virtqueue *vq)
>  			"%s: used_event_idx=%d, old=%d, new=%d\n",
>  			__func__, vhost_used_event(vq), old, new);
> 
> -		if ((vhost_need_event(vhost_used_event(vq), new, old) &&
> -					(vq->callfd >= 0)) ||
> -				unlikely(!signalled_used_valid)) {
> +		if ((vhost_need_event(vhost_used_event(vq), new, old) ||
> +					unlikely(!signalled_used_valid)) &&
> +				vq->callfd >= 0) {
>  			eventfd_write(vq->callfd, (eventfd_t) 1);
>  			if (dev->flags & VIRTIO_DEV_STATS_ENABLED)
>  				vq->stats.guest_notifications++;
> @@ -971,7 +971,7 @@ vhost_vring_call_packed(struct virtio_net *dev, struct
> vhost_virtqueue *vq)
>  	if (vhost_need_event(off, new, old))
>  		kick = true;
>  kick:
> -	if (kick) {
> +	if (kick && vq->callfd >= 0) {
>  		eventfd_write(vq->callfd, (eventfd_t)1);
>  		if (dev->flags & VIRTIO_DEV_STATS_ENABLED)
>  			vq->stats.guest_notifications++;
> --
> 2.39.2

Reviewed-by: Chenbo Xia <chenbo.xia at intel.com>