* [PATCH v3,net] virtio_net: Improve RSS key size validation
@ 2026-02-12 13:03 Srujana Challa
2026-02-12 14:40 ` Michael S. Tsirkin
0 siblings, 1 reply; 3+ messages in thread
From: Srujana Challa @ 2026-02-12 13:03 UTC (permalink / raw)
To: netdev, virtualization
Cc: pabeni, mst, jasowang, xuanzhuo, eperezma, davem, edumazet, kuba,
ndabilpuram, kshankar, schalla, stable
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)
+#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 */
+ 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);
+ }
+ }
+
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
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v3,net] virtio_net: Improve RSS key size validation
2026-02-12 13:03 [PATCH v3,net] virtio_net: Improve RSS key size validation Srujana Challa
@ 2026-02-12 14:40 ` Michael S. Tsirkin
2026-02-13 5:40 ` [EXTERNAL] " Srujana Challa
0 siblings, 1 reply; 3+ messages in thread
From: Michael S. Tsirkin @ 2026-02-12 14:40 UTC (permalink / raw)
To: Srujana Challa
Cc: netdev, virtualization, pabeni, jasowang, xuanzhuo, eperezma,
davem, edumazet, kuba, ndabilpuram, kshankar, stable
On Thu, Feb 12, 2026 at 06:33:40PM +0530, Srujana Challa wrote:
> 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?
> +#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?
> + }
> + }
> +
> 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
^ permalink raw reply [flat|nested] 3+ messages in thread* RE: [EXTERNAL] Re: [PATCH v3,net] virtio_net: Improve RSS key size validation
2026-02-12 14:40 ` Michael S. Tsirkin
@ 2026-02-13 5:40 ` Srujana Challa
0 siblings, 0 replies; 3+ messages in thread
From: Srujana Challa @ 2026-02-13 5:40 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: netdev@vger.kernel.org, virtualization@lists.linux.dev,
pabeni@redhat.com, jasowang@redhat.com,
xuanzhuo@linux.alibaba.com, eperezma@redhat.com,
davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
Nithin Kumar Dabilpuram, Shiva Shankar Kommula,
stable@vger.kernel.org
> On Thu, Feb 12, 2026 at 06:33:40PM +0530, Srujana Challa wrote:
> > 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?
It is still used for the rss_hash_key_data[VIRTIO_NET_RSS_MAX_KEY_SIZE] in struct virtnet_info.
Should I change it to use NETDEV_RSS_KEY_LEN?
>
>
> > +#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?
Will move.
>
> > + 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?
>
> > + }
> > + }
> > +
> > 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
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-02-12 13:03 [PATCH v3,net] virtio_net: Improve RSS key size validation Srujana Challa
2026-02-12 14:40 ` Michael S. Tsirkin
2026-02-13 5:40 ` [EXTERNAL] " Srujana Challa
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