rss_max_key_size in the virtio spec is the maximum key size supported by
the device, not a mandatory size the driver must use. Also the value 40
is a spec minimum, not a spec maximum.
The current code rejects RSS and can fail probe when the device reports a
larger rss_max_key_size than the driver buffer limit. Instead, clamp the
effective key length to min(device rss_max_key_size, NETDEV_RSS_KEY_LEN)
and keep RSS enabled.
This keeps probe working on devices that advertise larger maximum key sizes
while respecting the netdev RSS key buffer size limit.
Fixes: 3f7d9c1964fc ("virtio_net: Add hash_key_length check")
Cc: [email protected]
Signed-off-by: Srujana Challa <[email protected]>
---
v3:
- Moved RSS key validation checks to virtnet_validate.
- Add fixes: tag and CC -stable
v4:
- Use NETDEV_RSS_KEY_LEN instead of type_max for the maximum rss key size.
v5:
- Interpret rss_max_key_size as a maximum and clamp it to NETDEV_RSS_KEY_LEN.
- Do not disable RSS/HASH_REPORT when device rss_max_key_size exceeds
NETDEV_RSS_KEY_LEN.
- Drop the separate patch that replaced the runtime check with BUILD_BUG_ON.
drivers/net/virtio_net.c | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 022f60728721..b241c8dbb4e1 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -373,8 +373,6 @@ struct receive_queue {
struct xdp_buff **xsk_buffs;
};
-#define VIRTIO_NET_RSS_MAX_KEY_SIZE 40
-
/* Control VQ buffers: protected by the rtnl lock */
struct control_buf {
struct virtio_net_ctrl_hdr hdr;
@@ -478,7 +476,7 @@ struct virtnet_info {
/* Must be last as it ends in a flexible-array member. */
TRAILING_OVERLAP(struct virtio_net_rss_config_trailer, rss_trailer,
hash_key_data,
- u8 rss_hash_key_data[VIRTIO_NET_RSS_MAX_KEY_SIZE];
+ u8 rss_hash_key_data[NETDEV_RSS_KEY_LEN];
);
};
static_assert(offsetof(struct virtnet_info, rss_trailer.hash_key_data) ==
@@ -6717,6 +6715,7 @@ static int virtnet_probe(struct virtio_device *vdev)
struct virtnet_info *vi;
u16 max_queue_pairs;
int mtu = 0;
+ u16 key_sz;
/* Find if host supports multiqueue/rss virtio_net device */
max_queue_pairs = 1;
@@ -6851,14 +6850,13 @@ 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;
- }
+ key_sz = virtio_cread8(vdev, offsetof(struct virtio_net_config,
rss_max_key_size));
+
+ vi->rss_key_size = min_t(u16, key_sz, NETDEV_RSS_KEY_LEN);
+ if (key_sz > vi->rss_key_size)
+ dev_warn(&vdev->dev,
+ "rss_max_key_size=%u exceeds driver limit %u,
clamping\n",
+ key_sz, vi->rss_key_size);
vi->rss_hash_types_supported =
virtio_cread32(vdev, offsetof(struct virtio_net_config,
supported_hash_types));
--
2.25.1
