Re: [virtio-comment] [PATCH v5] virtio-net: support the RSS context

[Cornelia Huck <cohuck@redhat.com>]

On Fri, Nov 03 2023, Heng Qi <hengqi@linux.alibaba.com> wrote:

> Commit 84a1d9c48200 ("net: ethtool: extend RXNFC API to support RSS spreading of
> filter matches") adds support for RSS context as a destination for receive flow filters
> (see WIP work: https://lists.oasis-open.org/archives/virtio-comment/202308/msg00194.html).
>
> An RSS context consists of configurable parameters specified by receive-side scaling.
>
> Some use cases:
> 1. When users want some data flows to be steered to specific multiple rxqs, they can set
>    receive flow filter rules for these data flows to an RSS context with desired rxqs.
> 2. Traffic isolation. Used when users want the traffic of certain applications to occupy
>    several queues without being distubed.
>
> How to set/configure an RSS context:
> Assuming no RSS context has been created before.
> 1. ethtool -X eth0 context new start 5 equal 8
>
> This command creates an RSS context with an id=1 for eth0, and fills in the indirection
> table with rxq indexes 5-8 circularly. The hash key and hash types reuse the default
> RSS configuration.
>
> Then, we can use 'ethtool -x eth0 context 1' to query the above configuration.
>
> 2. ethtool -X eth0 context new start 6 equal 7 \
>    hkey 8f:bf:dd:11:23:58:d2:8a:00:31:d0:32:a3:b5:1f:\
>    1f:e4:d1:fe:47:7f:64:42:fd:d0:61:16:b8:b0:f9:71:e8:2d:36:7f:18:dd:4d:c8:f3
>
> This command creates an RSS context with an id=2 for eth0, and fills in the indirection
> table with rxq indexes 6-7 circularly. The hash key is 8f:bf:dd:11:23:58:d2:8a:00:31:d0\
> :32:a3:b5:1f:1f:e4:d1:fe:47:7f:64:42:fd:d0:61:16:b8:b0:f9:71:e8:2d:36:7f:18:dd:4d:c8:f3.
> Hash types reuse the default RSS configuration.
>
> 3. ethtool -N eth0 rx-flow-hash tcp4 sdfn context 1
>
> This command specifies the hash types for the RSS context whose id=1 on eth0.
> Now this RSS context only has the hash key to reuse the default RSS configuration.
>
> 4. ethtool -N eth0 flow-type udp4 src-ip 1.1.1.1 context 1
>
> This command configures a receive flow filter rule for eth0, and the data flow matching
> this rule will continue to select the final rxq according to the RSS context configuration
> with id=1.
>
> Fixes: https://github.com/oasis-tcs/virtio-spec/issues/178
> Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
> Signed-off-by: Parav Pandit <parav@nvidia.com>
> Acked-by: Satananda Burla <sburla@marvell.com>
> ---
> v4->v5:
>   1. Use 'u8 reserved[6]' instead of u16 padding to align the structure.
>
> v3->v4:
>   1. Rebase to Xuan's device stats patch.
>
> v2->v3:
>   1. Process Satananda's comments and add his ack tag.
>   2. Add link to fix issue and optimize commit log.
>
> v1->v2:
>   1. u8 to le16 for field rss_ctx_id.
>   2. Add normativation when device resetting. @Yuri Benditovich
>   3. Use ctrlq cmd to query rss context capability instead of reading config space. @Parav Pandit
>
>  device-types/net/description.tex        | 85 +++++++++++++++++++++++++
>  device-types/net/device-conformance.tex |  1 +
>  device-types/net/driver-conformance.tex |  1 +
>  3 files changed, 87 insertions(+)

So, what's the status here? The github issue still points to the
previous version (where you had asked for opening a vote.) There's only
the padding change in this version... can I get some ack from net folks
on whether this is ready for a vote?