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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Fri, 1 Dec 2023 16:10:18 -0800
Message-ID: <CAADnVQKWrvec6ap_7O0Z5uAJe-pdrhuJk8LRkmWvGMM4iF9Frg@mail.gmail.com>
Subject: Re: [PATCH ipsec-next v3 0/9] Add bpf_xdp_get_xfrm_state() kfunc
To:     Daniel Xu <dxu@dxuuu.xyz>
Cc:     Network Development <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
        clang-built-linux <llvm@lists.linux.dev>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>,
        Steffen Klassert <steffen.klassert@secunet.com>,
        antony.antony@secunet.com, Yonghong Song <yonghong.song@linux.dev>,
        Eddy Z <eddyz87@gmail.com>, devel@linux-ipsec.org
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On Fri, Dec 1, 2023 at 12:23=E2=80=AFPM Daniel Xu <dxu@dxuuu.xyz> wrote:
>
> This patchset adds two kfunc helpers, bpf_xdp_get_xfrm_state() and
> bpf_xdp_xfrm_state_release() that wrap xfrm_state_lookup() and
> xfrm_state_put(). The intent is to support software RSS (via XDP) for
> the ongoing/upcoming ipsec pcpu work [0]. Recent experiments performed
> on (hopefully) reproducible AWS testbeds indicate that single tunnel
> pcpu ipsec can reach line rate on 100G ENA nics.
>
> Note this patchset only tests/shows generic xfrm_state access. The
> "secret sauce" (if you can really even call it that) involves accessing
> a soon-to-be-upstreamed pcpu_num field in xfrm_state. Early example is
> available here [1].
>
> [0]: https://datatracker.ietf.org/doc/draft-ietf-ipsecme-multi-sa-perform=
ance/03/
> [1]: https://github.com/danobi/xdp-tools/blob/e89a1c617aba3b50d990f779357=
d6ce2863ecb27/xdp-bench/xdp_redirect_cpumap.bpf.c#L385-L406
>
> Changes from v2:
> * Fix/simplify BPF_CORE_WRITE_BITFIELD() algorithm
> * Added verifier tests for bitfield writes
> * Fix state leakage across test_tunnel subtests
>
> Changes from v1:
> * Move xfrm tunnel tests to test_progs
> * Fix writing to opts->error when opts is invalid
> * Use __bpf_kfunc_start_defs()
> * Remove unused vxlanhdr definition
> * Add and use BPF_CORE_WRITE_BITFIELD() macro
> * Make series bisect clean
>
> Changes from RFCv2:
> * Rebased to ipsec-next
> * Fix netns leak
>
> Changes from RFCv1:
> * Add Antony's commit tags
> * Add KF_ACQUIRE and KF_RELEASE semantics
>
> Daniel Xu (9):
>   bpf: xfrm: Add bpf_xdp_get_xfrm_state() kfunc
>   bpf: xfrm: Add bpf_xdp_xfrm_state_release() kfunc
>   libbpf: Add BPF_CORE_WRITE_BITFIELD() macro
>   bpf: selftests: test_loader: Support __btf_path() annotation
>   libbpf: selftests: Add verifier tests for CO-RE bitfield writes
>   bpf: selftests: test_tunnel: Setup fresh topology for each subtest
>   bpf: selftests: test_tunnel: Use vmlinux.h declarations
>   bpf: selftests: Move xfrm tunnel test to test_progs
>   bpf: xfrm: Add selftest for bpf_xdp_get_xfrm_state()
>
>  include/net/xfrm.h                            |   9 +
>  net/xfrm/Makefile                             |   1 +
>  net/xfrm/xfrm_policy.c                        |   2 +
>  net/xfrm/xfrm_state_bpf.c                     | 128 ++++++++++++++
>  tools/lib/bpf/bpf_core_read.h                 |  34 ++++
>  .../selftests/bpf/prog_tests/test_tunnel.c    | 162 +++++++++++++++++-
>  .../selftests/bpf/prog_tests/verifier.c       |   2 +
>  tools/testing/selftests/bpf/progs/bpf_misc.h  |   1 +
>  .../selftests/bpf/progs/bpf_tracing_net.h     |   1 +
>  .../selftests/bpf/progs/test_tunnel_kern.c    | 138 ++++++++-------
>  .../bpf/progs/verifier_bitfield_write.c       | 100 +++++++++++
>  tools/testing/selftests/bpf/test_loader.c     |   7 +
>  tools/testing/selftests/bpf/test_tunnel.sh    |  92 ----------
>  13 files changed, 522 insertions(+), 155 deletions(-)

I really think this should go via bpf-next tree.
The bpf changes are much bigger than ipsec.