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

[Daniel Xu]

On Fri, Dec 01, 2023 at 04:10:18PM -0800, Alexei Starovoitov wrote:
> On Fri, Dec 1, 2023 at 12:23 PM Daniel Xu <dxu@xxxxxxxxx> 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.

Ack. Ended up picking up a lot of stuff along the way.