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2025-07-16doc: xdp: Clarify driver implementation for XDP Rx metadataSong Yoong Siang
Clarify that drivers must remove device-reserved metadata from the data_meta area before passing frames to XDP programs. Additionally, expand the explanation of how userspace and BPF programs should coordinate the use of METADATA_SIZE, and add a detailed diagram to illustrate pointer adjustments and metadata layout. Also describe the requirements and constraints enforced by bpf_xdp_adjust_meta(). Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://lore.kernel.org/r/20250716154846.3513575-1-yoong.siang.song@intel.com
2023-12-13xdp: Add VLAN tag hintLarysa Zaremba
Implement functionality that enables drivers to expose VLAN tag to XDP code. VLAN tag is represented by 2 variables: - protocol ID, which is passed to bpf code in BE - VLAN TCI, in host byte order Acked-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Larysa Zaremba <larysa.zaremba@intel.com> Acked-by: Jesper Dangaard Brouer <hawk@kernel.org> Link: https://lore.kernel.org/r/20231205210847.28460-10-larysa.zaremba@intel.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-11-29xsk: Document tx_metadata_len layoutStanislav Fomichev
- how to use - how to query features - pointers to the examples Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20231127190319.1190813-7-sdf@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-09-15bpf: expose information about supported xdp metadata kfuncStanislav Fomichev
Add new xdp-rx-metadata-features member to netdev netlink which exports a bitmask of supported kfuncs. Most of the patch is autogenerated (headers), the only relevant part is netdev.yaml and the changes in netdev-genl.c to marshal into netlink. Example output on veth: $ ip link add veth0 type veth peer name veth1 # ifndex == 12 $ ./tools/net/ynl/samples/netdev 12 Select ifc ($ifindex; or 0 = dump; or -2 ntf check): 12 veth1[12] xdp-features (23): basic redirect rx-sg xdp-rx-metadata-features (3): timestamp hash xdp-zc-max-segs=0 Cc: netdev@vger.kernel.org Cc: Willem de Bruijn <willemb@google.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20230913171350.369987-3-sdf@google.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-03-22xdp: bpf_xdp_metadata use EOPNOTSUPP for no driver supportJesper Dangaard Brouer
When driver doesn't implement a bpf_xdp_metadata kfunc the fallback implementation returns EOPNOTSUPP, which indicate device driver doesn't implement this kfunc. Currently many drivers also return EOPNOTSUPP when the hint isn't available, which is ambiguous from an API point of view. Instead change drivers to return ENODATA in these cases. There can be natural cases why a driver doesn't provide any hardware info for a specific hint, even on a frame to frame basis (e.g. PTP). Lets keep these cases as separate return codes. When describing the return values, adjust the function kernel-doc layout to get proper rendering for the return values. Fixes: ab46182d0dcb ("net/mlx4_en: Support RX XDP metadata") Fixes: bc8d405b1ba9 ("net/mlx5e: Support RX XDP metadata") Fixes: 306531f0249f ("veth: Support RX XDP metadata") Fixes: 3d76a4d3d4e5 ("bpf: XDP metadata RX kfuncs") Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Stanislav Fomichev <sdf@google.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Acked-by: Tariq Toukan <tariqt@nvidia.com> Link: https://lore.kernel.org/r/167940675120.2718408.8176058626864184420.stgit@firesoul Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-01-23bpf: Document XDP RX metadataStanislav Fomichev
Document all current use-cases and assumptions. Cc: John Fastabend <john.fastabend@gmail.com> Cc: David Ahern <dsahern@gmail.com> Cc: Martin KaFai Lau <martin.lau@linux.dev> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Willem de Bruijn <willemb@google.com> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Anatoly Burakov <anatoly.burakov@intel.com> Cc: Alexander Lobakin <alexandr.lobakin@intel.com> Cc: Magnus Karlsson <magnus.karlsson@gmail.com> Cc: Maryam Tahhan <mtahhan@redhat.com> Cc: xdp-hints@xdp-project.net Cc: netdev@vger.kernel.org Acked-by: David Vernet <void@manifault.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20230119221536.3349901-2-sdf@google.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>