Please see the first patch in the series for the overall design and use-cases. Changes since last RFC: - drop ice/bnxt example implementation (Alexander) -ENOHARDWARE to test - fix/test mlx4 implementation Confirmed that I get reasonable looking timestamp. The last patch in the series is the small xsk program that can be used to dump incoming metadata. - bpf_push64/bpf_pop64 (Alexei) x86_64+arm64(untested)+disassembler - struct xdp_to_skb_metadata -> struct xdp_skb_metadata (Toke) s/xdp_to_skb/xdp_skb/ - Documentation/bpf/xdp-rx-metadata.rst Documents functionality, assumptions and limitations. - bpf_xdp_metadata_export_to_skb returns true/false (Martin) Plus xdp_md->skb_metadata field to access it. - BPF_F_XDP_HAS_METADATA flag (Toke/Martin) Drop magic, use the flag instead. - drop __randomize_layout Not sure it's possible to sanely expose it via UAPI. Because every .o potentially gets its own randomized layout, test_progs refuses to link. - remove __net_timestamp in veth driver (John/Jesper) Instead, calling ktime_get from the kfunc; enough for the selftests. Future work on RX side: - Support more devices besides veth and mlx4 - Support more metadata besides RX timestamp. - Convert skb_metadata_set() callers to xdp_convert_skb_metadata() which handles extra xdp_skb_metadata Prior art (to record pros/cons for different approaches): - Stable UAPI approach: https://lore.kernel.org/bpf/20220628194812.1453059-1-alexandr.lobakin@xxxxxxxxx/ - Metadata+BTF_ID appoach: https://lore.kernel.org/bpf/166256538687.1434226.15760041133601409770.stgit@firesoul/ - kfuncs v2 RFC: https://lore.kernel.org/bpf/20221027200019.4106375-1-sdf@xxxxxxxxxx/ - kfuncs v1 RFC: https://lore.kernel.org/bpf/20221104032532.1615099-1-sdf@xxxxxxxxxx/ Cc: John Fastabend <john.fastabend@xxxxxxxxx> Cc: David Ahern <dsahern@xxxxxxxxx> Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx> Cc: Jakub Kicinski <kuba@xxxxxxxxxx> Cc: Willem de Bruijn <willemb@xxxxxxxxxx> Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> Cc: Anatoly Burakov <anatoly.burakov@xxxxxxxxx> Cc: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx> Cc: Magnus Karlsson <magnus.karlsson@xxxxxxxxx> Cc: Maryam Tahhan <mtahhan@xxxxxxxxxx> Cc: xdp-hints@xxxxxxxxxxxxxxx Cc: netdev@xxxxxxxxxxxxxxx Stanislav Fomichev (11): bpf: Document XDP RX metadata bpf: Introduce bpf_patch bpf: Support inlined/unrolled kfuncs for xdp metadata bpf: Implement hidden BPF_PUSH64 and BPF_POP64 instructions veth: Support rx timestamp metadata for xdp xdp: Carry over xdp metadata into skb context selftests/bpf: Verify xdp_metadata xdp->af_xdp path selftests/bpf: Verify xdp_metadata xdp->skb path mlx4: Introduce mlx4_xdp_buff wrapper for xdp_buff mxl4: Support rx timestamp metadata for xdp selftests/bpf: Simple program to dump XDP RX metadata Documentation/bpf/kfuncs.rst | 8 + Documentation/bpf/xdp-rx-metadata.rst | 109 +++++ arch/arm64/net/bpf_jit_comp.c | 8 + arch/x86/net/bpf_jit_comp.c | 8 + .../net/ethernet/mellanox/mlx4/en_netdev.c | 2 + drivers/net/ethernet/mellanox/mlx4/en_rx.c | 68 ++- drivers/net/veth.c | 22 +- include/linux/bpf.h | 1 + include/linux/bpf_patch.h | 29 ++ include/linux/btf.h | 1 + include/linux/btf_ids.h | 4 + include/linux/filter.h | 23 + include/linux/mlx4/device.h | 7 + include/linux/netdevice.h | 5 + include/linux/skbuff.h | 4 + include/net/xdp.h | 41 ++ include/uapi/linux/bpf.h | 12 + kernel/bpf/Makefile | 2 +- kernel/bpf/bpf_patch.c | 77 +++ kernel/bpf/disasm.c | 6 + kernel/bpf/syscall.c | 28 +- kernel/bpf/verifier.c | 80 ++++ net/core/dev.c | 7 + net/core/filter.c | 40 ++ net/core/skbuff.c | 20 + net/core/xdp.c | 184 +++++++- tools/include/uapi/linux/bpf.h | 12 + tools/testing/selftests/bpf/.gitignore | 1 + tools/testing/selftests/bpf/DENYLIST.s390x | 1 + tools/testing/selftests/bpf/Makefile | 8 +- .../selftests/bpf/prog_tests/xdp_metadata.c | 440 ++++++++++++++++++ .../selftests/bpf/progs/xdp_hw_metadata.c | 99 ++++ .../selftests/bpf/progs/xdp_metadata.c | 114 +++++ tools/testing/selftests/bpf/xdp_hw_metadata.c | 404 ++++++++++++++++ tools/testing/selftests/bpf/xdp_hw_metadata.h | 6 + 35 files changed, 1856 insertions(+), 25 deletions(-) create mode 100644 Documentation/bpf/xdp-rx-metadata.rst create mode 100644 include/linux/bpf_patch.h create mode 100644 kernel/bpf/bpf_patch.c 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/xdp_hw_metadata.c create mode 100644 tools/testing/selftests/bpf/xdp_hw_metadata.h -- 2.38.1.431.g37b22c650d-goog
