[bpf-next,v4,00/15] xdp: hints via kfuncs

Message

Stanislav Fomichev Dec. 13, 2022, 2:35 a.m. UTC

Please see the first patch in the series for the overall
design and use-cases.

See the following email from Toke for the per-packet metadata overhead:
https://lore.kernel.org/bpf/[e-mail]/T/#m49d48ea08d525ec88360c7d14c4d34fb0e45e798

Recent changes:

- Drop _supported kfuncs, return status from the existing ones,
  return the actual payload via arguments (Jakub)

- Use 'device-bound' instead of 'offloaded' in existing error message (Jakub)

- Move offload init into late_initcall (Jakub)

- Separate xdp_metadata_ops to host netdev kfunc pointers (Jakub)

- Remove forward declarations (Jakub)

- Rename more offload routines to dev_bound (Jakub)
  bpf_offload_resolve_kfunc -> bpf_dev_bound_resolve_kfunc
  bpf_offload_bound_netdev_unregister -> bpf_dev_bound_netdev_unregister
  bpf_prog_offload_init -> bpf_prog_dev_bound_init
  bpf_prog_offload_destroy -> bpf_prog_dev_bound_destroy
  maybe_remove_bound_netdev -> bpf_dev_bound_try_remove_netdev

- Move bpf_prog_is_dev_bound check into bpf_prog_map_compatible (Toke)

- Prohibit metadata kfuncs unless device-bound (Toke)

- Adjust selftest to exercise freplace + include the path (Toke)

- Take rtnl in bpf_prog_offload_destroy to avoid the race (Martin)

- BPF_F_XDP_HAS_METADATA -> BPF_F_XDP_DEV_BOUND_ONLY (Martin)

- Prohibit only metadata kfuncs, not all (Alexei/Martin)

- Try to fix xdp_hw_metadata.c build issue on CI (Alexei)

  Wasn't able to reproduce it locally, so trying my best guess...

- mlx4 -> mlx4_en (Tariq)

  Plus other issues like using net/mlx4 prefix and using mlx4_en_xdp_buff
  instead of mlx4_xdp_buff. Applied those same patterns to mlx5.

- Separate device-bound changes into separate patch to make it easier to
  review

Prior art (to record pros/cons for different approaches):

- Stable UAPI approach:
  https://lore.kernel.org/bpf/[e-mail]/
- Metadata+BTF_ID appoach:
  https://lore.kernel.org/bpf/166256538687.1434226.15760041133601409770.stgit@firesoul/
- v3:
  https://lore.kernel.org/bpf/[e-mail]/
- v2:
  https://lore.kernel.org/bpf/[e-mail]/
- v1:
  https://lore.kernel.org/bpf/[e-mail]/
- kfuncs v2 RFC:
  https://lore.kernel.org/bpf/[e-mail]/
- kfuncs v1 RFC:
  https://lore.kernel.org/bpf/[e-mail]/

Cc: John Fastabend <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Martin KaFai Lau <[e-mail]>
Cc: Jakub Kicinski <[e-mail]>
Cc: Willem de Bruijn <[e-mail]>
Cc: Jesper Dangaard Brouer <[e-mail]>
Cc: Anatoly Burakov <[e-mail]>
Cc: Alexander Lobakin <[e-mail]>
Cc: Magnus Karlsson <[e-mail]>
Cc: Maryam Tahhan <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]

Stanislav Fomichev (11):
  bpf: Document XDP RX metadata
  bpf: Rename bpf_{prog,map}_is_dev_bound to is_offloaded
  bpf: Introduce device-bound XDP programs
  selftests/bpf: Update expected test_offload.py messages
  bpf: XDP metadata RX kfuncs
  veth: Introduce veth_xdp_buff wrapper for xdp_buff
  veth: Support RX XDP metadata
  selftests/bpf: Verify xdp_metadata xdp->af_xdp path
  net/mlx4_en: Introduce wrapper for xdp_buff
  net/mlx4_en: Support RX XDP metadata
  selftests/bpf: Simple program to dump XDP RX metadata

Toke Høiland-Jørgensen (4):
  bpf: Support consuming XDP HW metadata from fext programs
  xsk: Add cb area to struct xdp_buff_xsk
  net/mlx5e: Introduce wrapper for xdp_buff
  net/mlx5e: Support RX XDP metadata

 Documentation/bpf/xdp-rx-metadata.rst         |  90 ++++
 drivers/net/ethernet/mellanox/mlx4/en_clock.c |  13 +-
 .../net/ethernet/mellanox/mlx4/en_netdev.c    |   6 +
 drivers/net/ethernet/mellanox/mlx4/en_rx.c    |  63 ++-
 drivers/net/ethernet/mellanox/mlx4/mlx4_en.h  |   5 +
 drivers/net/ethernet/mellanox/mlx5/core/en.h  |  11 +-
 .../net/ethernet/mellanox/mlx5/core/en/xdp.c  |  26 +-
 .../net/ethernet/mellanox/mlx5/core/en/xdp.h  |  11 +-
 .../ethernet/mellanox/mlx5/core/en/xsk/rx.c   |  35 +-
 .../ethernet/mellanox/mlx5/core/en/xsk/rx.h   |   2 +
 .../net/ethernet/mellanox/mlx5/core/en_main.c |   6 +
 .../net/ethernet/mellanox/mlx5/core/en_rx.c   |  99 +++--
 drivers/net/netdevsim/bpf.c                   |   4 -
 drivers/net/veth.c                            |  80 ++--
 include/linux/bpf.h                           |  39 +-
 include/linux/netdevice.h                     |   7 +
 include/net/xdp.h                             |  25 ++
 include/net/xsk_buff_pool.h                   |   5 +
 include/uapi/linux/bpf.h                      |   5 +
 kernel/bpf/core.c                             |  11 +-
 kernel/bpf/offload.c                          | 360 +++++++++------
 kernel/bpf/syscall.c                          |  35 +-
 kernel/bpf/verifier.c                         |  56 ++-
 net/core/dev.c                                |   9 +-
 net/core/filter.c                             |   2 +-
 net/core/xdp.c                                |  44 ++
 tools/include/uapi/linux/bpf.h                |   5 +
 tools/testing/selftests/bpf/.gitignore        |   1 +
 tools/testing/selftests/bpf/Makefile          |   8 +-
 .../selftests/bpf/prog_tests/xdp_metadata.c   | 412 ++++++++++++++++++
 .../selftests/bpf/progs/xdp_hw_metadata.c     |  81 ++++
 .../selftests/bpf/progs/xdp_metadata.c        |  56 +++
 .../selftests/bpf/progs/xdp_metadata2.c       |  23 +
 tools/testing/selftests/bpf/test_offload.py   |  10 +-
 tools/testing/selftests/bpf/xdp_hw_metadata.c | 405 +++++++++++++++++
 tools/testing/selftests/bpf/xdp_metadata.h    |  15 +
 36 files changed, 1780 insertions(+), 285 deletions(-)
 create mode 100644 Documentation/bpf/xdp-rx-metadata.rst
 create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_metadata.c
 create mode 100644 tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
 create mode 100644 tools/testing/selftests/bpf/progs/xdp_metadata.c
 create mode 100644 tools/testing/selftests/bpf/progs/xdp_metadata2.c
 create mode 100644 tools/testing/selftests/bpf/xdp_hw_metadata.c
 create mode 100644 tools/testing/selftests/bpf/xdp_metadata.h