Re: [PATCH v3,net] virtio_net: Improve RSS key size validation
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2026-02-12 14:40:57
Also in:
stable, virtualization
On Thu, Feb 12, 2026 at 06:33:40PM +0530, Srujana Challa wrote:
quoted hunk ↗ jump to hunk
Replace hardcoded RSS max key size limit with a type based definition. Add validation for RSS key size against spec minimum (40 bytes). When validation fails, gracefully disable RSS features and continue initialization rather than failing completely. Cc: stable@vger.kernel.org Fixes: 3f7d9c1964fc ("virtio_net: Add hash_key_length check") Signed-off-by: Srujana Challa <schalla@marvell.com> v3: - Moved RSS key validation checks to virtnet_validate. - Add fixes: tag and CC -stable --- drivers/net/virtio_net.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-)diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index db88dcaefb20..e61cea50dcab 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c@@ -381,7 +381,9 @@ struct receive_queue { struct xdp_buff **xsk_buffs; }; -#define VIRTIO_NET_RSS_MAX_KEY_SIZE 40 +#define VIRTIO_NET_RSS_MAX_KEY_SIZE \ + (type_max(((struct virtio_net_config *)0)->rss_max_key_size) + 1)
+1 here really unintuitive. It does not look like it's still used, though?
quoted hunk ↗ jump to hunk
+#define VIRTIO_NET_RSS_MIN_KEY_SIZE 40 /* Control VQ buffers: protected by the rtnl lock */ struct control_buf {@@ -6627,6 +6629,24 @@ static int virtnet_validate(struct virtio_device *vdev) __virtio_clear_bit(vdev, VIRTIO_NET_F_STANDBY); } + if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS) || + virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT)) { + u8 key_sz = virtio_cread8(vdev, + offsetof(struct virtio_net_config, + rss_max_key_size)); + /* Spec requires at least 40 bytes */
move the define here then?
+ if (key_sz < VIRTIO_NET_RSS_MIN_KEY_SIZE) {
+ dev_warn(&vdev->dev,
+ "rss_max_key_size=%u is less than spec minimum %u, disabling RSS\n",
+ key_sz, VIRTIO_NET_RSS_MIN_KEY_SIZE);
+ if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS))
+ __virtio_clear_bit(vdev, VIRTIO_NET_F_RSS);
+ if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT))
+ __virtio_clear_bit(vdev,
+ VIRTIO_NET_F_HASH_REPORT);why not clear them unconditionally?
quoted hunk ↗ jump to hunk
+ } + } + return 0; }@@ -6839,13 +6859,6 @@ static int virtnet_probe(struct virtio_device *vdev) if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_key_size = virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size)); - if (vi->rss_key_size > VIRTIO_NET_RSS_MAX_KEY_SIZE) { - dev_err(&vdev->dev, "rss_max_key_size=%u exceeds the limit %u.\n", - vi->rss_key_size, VIRTIO_NET_RSS_MAX_KEY_SIZE); - err = -EINVAL; - goto free; - } - vi->rss_hash_types_supported = virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types)); vi->rss_hash_types_supported &=-- 2.25.1