diff options
| author | Brett Creeley <brett.creeley@amd.com> | 2026-04-16 14:21:21 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-04-23 09:35:53 -0700 |
| commit | 3bc06da858ef17cfe94b49efc0d9713727012835 (patch) | |
| tree | 711ce4335c903c465d45e1f715f3190d2eaef50e | |
| parent | d40831b016b4986e70d20d0ad14e6a0c62318986 (diff) | |
virtio_net: sync rss_trailer.max_tx_vq on queue_pairs change via VQ_PAIRS_SET
When netif_is_rxfh_configured() is true (i.e., the user has explicitly
configured the RSS indirection table), virtnet_set_queues() skips the
RSS update path and falls through to the VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET
command to change the number of queue pairs. However, it does not update
vi->rss_trailer.max_tx_vq to reflect the new queue_pairs value.
This causes a mismatch between vi->curr_queue_pairs and
vi->rss_trailer.max_tx_vq. Any subsequent RSS reconfiguration (e.g.,
via ethtool -X) calls virtnet_commit_rss_command(), which sends the
stale max_tx_vq to the device, silently reverting the queue count.
Reproduction:
1. User configured RSS
ethtool -X eth0 equal 8
2. VQ_PAIRS_SET path; max_tx_vq stays 16
ethtool -L eth0 combined 12
3. RSS commit uses max_tx_vq=16 instead of 12
ethtool -X eth0 equal 4
Fix this by updating vi->rss_trailer.max_tx_vq after a successful
VQ_PAIRS_SET command when RSS is enabled, keeping it in sync with
curr_queue_pairs.
Fixes: 50bfcaedd78e ("virtio_net: Update rss when set queue")
Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://patch.msgid.link/20260416212121.29073-1-brett.creeley@amd.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/virtio_net.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index bfb566fecb92..f4adcfee7a80 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3759,6 +3759,12 @@ static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs) queue_pairs); return -EINVAL; } + + /* Keep max_tx_vq in sync so that a later RSS command does not + * revert queue_pairs to a stale value. + */ + if (vi->has_rss) + vi->rss_trailer.max_tx_vq = cpu_to_le16(queue_pairs); succ: vi->curr_queue_pairs = queue_pairs; if (dev->flags & IFF_UP) { |