Re: [PATCH ipsec-next v3 0/9] Add bpf_xdp_get_xfrm_state() kfunc

Alexei Starovoitov
2023-12-02T00:11:42Z

On Fri, Dec 1, 2023 at 12:23 PM 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-performance/03/
> [1]: https://github.com/danobi/xdp-tools/blob/e89a1c617aba3b50d990f779357d6ce2863ecb27/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.