On Fri, 22 Mar 2024 03:21:21 -0700, Breno Leitao <lei...@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 <lei...@debian.org> wrote:
>
> > > 4) 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.
Thanks.
