Re: [PATCH v3 3/4] vhost: fix invalid call FD handling

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 5/31/23 08:12, Xia, Chenbo wrote:
>> -----Original Message-----
>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Sent: Tuesday, May 30, 2023 8:54 PM
>> To: Eelco Chaudron <echaudro@redhat.com>; Xia, Chenbo
>> <chenbo.xia@intel.com>; david.marchand@redhat.com
>> Cc: dev@dpdk.org
>> Subject: Re: [PATCH v3 3/4] vhost: fix invalid call FD handling
>>
>>
>>
>> On 5/17/23 11:09, Eelco Chaudron wrote:
>>> 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")
>>>
>>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>>> Signed-off-by: Eelco Chaudron <echaudro@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 37609c7c8d..23a4e2b1a7 100644
>>> --- a/lib/vhost/vhost.h
>>> +++ b/lib/vhost/vhost.h
>>> @@ -903,9 +903,9 @@ 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)
>>>    				__atomic_fetch_add(&vq->stats.guest_notifications,
>>> @@ -974,7 +974,7 @@ 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->notify_ops->guest_notified)
>>>    			dev->notify_ops->guest_notified(dev->vid);
>>>
>>
>> Reporting Chenbo's R-by, from the VDUSE series RFC:
>>
>> Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
> 
> Thanks Maxime! Btw: what's your plan of the same fix in VDUSE series, do you plan
> to drop it in VDUSE series or?

Yes, I'm rebasing my VDUSE series on top of Eelco's.
I just need the release note update for the new API, and I'll push Eelco
series to next-virtio.

Maxime

> Thanks,
> Chenbo
>