virtio_net_can_receive() checks if the queue is ready, but RSS will
change the queue to use so, strictly speaking, we may still be able to
receive the packet even if the queue initially provided is not ready.
Perform RSS before virtio_net_can_receive() to cover such a case.

Fixes: 4474e37a5b3a ("virtio-net: implement RX RSS processing")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 hw/net/virtio-net.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 755530c035e4..3ee1ebd88daa 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1901,10 +1901,6 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
     size_t offset, i, guest_offset, j;
     ssize_t err;
 
-    if (!virtio_net_can_receive(nc)) {
-        return -1;
-    }
-
     if (!no_rss && n->rss_data.enabled && n->rss_data.enabled_software_rss) {
         int index = virtio_net_process_rss(nc, buf, size, &extra_hdr);
         if (index >= 0) {
@@ -1913,6 +1909,10 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf,
         }
     }
 
+    if (!virtio_net_can_receive(nc)) {
+        return -1;
+    }
+
     /* hdr_len refers to the header we supply to the guest */
     if (!virtio_net_has_buffers(q, size + n->guest_hdr_len - n->host_hdr_len)) {
         return 0;

-- 
2.46.0

On Sun, Sep 15, 2024 at 9:07 AM Akihiko Odaki <akihiko.odaki@daynix.com> wrote:
>
> virtio_net_can_receive() checks if the queue is ready, but RSS will
> change the queue to use so, strictly speaking, we may still be able to
> receive the packet even if the queue initially provided is not ready.
> Perform RSS before virtio_net_can_receive() to cover such a case.
>
> Fixes: 4474e37a5b3a ("virtio-net: implement RX RSS processing")
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
>  hw/net/virtio-net.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>

The patch does not apply cleanly:

Applying: virtio-net: Fix hash reporting when the queue changes
error: patch failed: hw/net/virtio-net.c:1901
error: hw/net/virtio-net.c: patch does not apply
Patch failed at 0004 virtio-net: Fix hash reporting when the queue changes
hint: Use 'git am --show-current-patch=diff' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

Thansk