Hello Xuan,
On Mon, Mar 25, 2024 at 01:57:53PM +0800, Xuan Zhuo wrote:
On Fri, 22 Mar 2024 03:21:21 -0700, Breno Leitao leitao@debian.org wrote:
Hello Xuan,
On Fri, Mar 22, 2024 at 10:00:22AM +0800, Xuan Zhuo wrote:
On Thu, 21 Mar 2024 09:54:30 -0700, Breno Leitao leitao@debian.org wrote:
- Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size;
if (vi->has_rss || vi->has_rss_hash_report) { vi->rss_indir_table_size = virtio_cread16(vdev, offsetof(struct virtio_net_config, rss_max_indirection_table_length)); vi->rss_key_size = virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
vi->rss_hash_types_supported = virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types)); vi->rss_hash_types_supported &= ~(VIRTIO_NET_RSS_HASH_TYPE_IP_EX | VIRTIO_NET_RSS_HASH_TYPE_TCP_EX | VIRTIO_NET_RSS_HASH_TYPE_UDP_EX); dev->hw_features |= NETIF_F_RXHASH;}
vi->rss_key_size is initiated here, I wonder if there is something wrong?
Not really, the code above is never executed (in my machines). This is because `vi->has_rss` and `vi->has_rss_hash_report` are both unset.
Looking further, vdev does not have the VIRTIO_NET_F_RSS and VIRTIO_NET_F_HASH_REPORT features.
Also, when I run `ethtool -x`, I got:
# ethtool -x eth0 RX flow hash indirection table for eth0 with 1 RX ring(s): Operation not supported RSS hash key: Operation not supported RSS hash function: toeplitz: on xor: off crc32: off
The spec saies: Note that if the device offers VIRTIO_NET_F_HASH_REPORT, even if it supports only one pair of virtqueues, it MUST support at least one of commands of VIRTIO_NET_CTRL_MQ class to configure reported hash parameters:
If the device offers VIRTIO_NET_F_RSS, it MUST support VIRTIO_NET_CTRL_MQ_RSS_CONFIG command per 5.1.6.5.7.1.
Otherwise the device MUST support VIRTIO_NET_CTRL_MQ_HASH_CONFIG command per 5.1.6.5.6.4.
So if we have not anyone of `vi->has_rss` and `vi->has_rss_hash_report`, we should return from virtnet_set_rxfh directly.
Makes sense. Although it is not clear to me how vi->has_rss_hash_report is related here, but, I am convinced that we shouldn't do any RSS operation if the device doesn't have the RSS feature, i.e, vi->has_rss is false.
That said, I am thinking about something like this. How does it sound?
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 5a7700b103f8..8c1ad7361cf2 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3780,6 +3780,9 @@ static int virtnet_set_rxfh(struct net_device *dev, struct virtnet_info *vi = netdev_priv(dev); int i; + if (!vi->has_rss) + return -EOPNOTSUPP; + if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE && rxfh->hfunc != ETH_RSS_HASH_TOP) return -EOPNOTSUPP;
Thanks!