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

[Maxime Coquelin]

On 5/31/23 08:12, Xia, Chenbo wrote:

-----Original Message-----
From: Maxime Coquelin <maxime.coque...@redhat.com>
Sent: Tuesday, May 30, 2023 8:54 PM
To: Eelco Chaudron <echau...@redhat.com>; Xia, Chenbo
<chenbo....@intel.com>; david.march...@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.coque...@redhat.com>
Signed-off-by: Eelco Chaudron <echau...@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....@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