SRv6 inner header based RSS.

[Nobuhiro MIKI <nmiki@yahoo-corp.jp>]

Hi dpdk team,

I was investigating to achieve RSS (Receive Side Scaling) based
on the inner header for SRv6 packets. However, I am not getting
it to work, so any comments would be appreciated.

I am checking the RSS statistics with "show port xstats" command
in dpdk-testpmd as shown below. One port has four queues. However,
I have confirmed that only the first queue has incoming packets.

    $ sudo . /build/app/dpdk-testpmd -n 4 -l 0-3 -a 0000:04:00.0 -a 0000:04:00.1 -- -i --rxq=4 --txq=4
    testpmd> start tx_first
    testpmd> clear port xstats all
    testpmd> show port xstats 0

The first approach I tried is to specify "level-inner" in the RSS
configuration as shown below. However, hashing by the inner header
could not be achieved.

    testpmd> port config all rss level-inner
    Port 0 modified RSS hash function based on hardware support,requested:0x80000000000a38c configured:0xa38c
    Port 1 modified RSS hash function based on hardware support,requested:0x8000000000000a38c configured:0xa38c
    rss_hf 0x8000000000000a38c

The second approach is to use the RSS action of rte_flow [1, 2].
I've tried a few things, but they don't seem to work.

    testpmd> flow create 0 ingress pattern eth / ipv6 / ipv4 / tcp / end actions rss level 2 types ip tcp end queues 0 1 2 3 end / end
    port_flow_complain(): Caught PMD error type 13 (specific pattern item): cause: 0x7ffc8c5b7af0, multiple L3 layers not supported. A: Operation not supported

    testpmd> flow create 0 ingress pattern eth / ipv6 has_route_ext is 1 / ipv4 / tcp / end actions rss level 2 types ip tcp end queues 0 1 2 3 end / end
    Bad arguments

    testpmd> flow create 0 ingress pattern eth / ipv6 / ipv6_route_ext / ipv4 / tcp / end actions rss level 2 types ip tcp end queues 0 1 2 3 end / end
    port_flow_complain(): Caught PMD error type 13 (specific pattern item): item not supported: Operation not supported

The OS is RHEL 9.1, the NIC is Mellanox ConnectX-6 Dx, and DPDK is
the master branch. Is there any misconfiguration or misunderstanding?

[1]: https://doc.dpdk.org/guides/prog_guide/rte_flow.html
[2]: https://github.com/DPDK/dpdk/commit/be944d46cacc49a869388afe02871a6474b95ee5

Best Regards,
Nobuhiro Miki