[[RFC xdp-hints] 09/16] net/xdp: Support for generic XDP hints
From: Ederson de Souza <hidden>
Date: 2021-08-03 01:03:54
Subsystem:
networking drivers, networking [general], the rest, xdp (express data path), xdp sockets (af_xdp) · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Alexei Starovoitov, Daniel Borkmann, David S. Miller, Jesper Dangaard Brouer, John Fastabend, Magnus Karlsson, Maciej Fijalkowski
XDP hints are meta information about an XDP packet. This patch provides macros that define a base set of hints, that drivers can use to implement XDP hints support - as well as expand on that. A future patch will show these macros being used by the igc driver. Signed-off-by: Ederson de Souza <redacted> --- include/net/xdp.h | 62 +++++++++++++++++++++++++++++++++++++ include/uapi/linux/if_xdp.h | 3 ++ 2 files changed, 65 insertions(+)
diff --git a/include/net/xdp.h b/include/net/xdp.h
index ad5b02dcb6f4..59a0b91e1975 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h@@ -76,6 +76,68 @@ struct xdp_buff { u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/ }; +/* + * This is what the generic xdp hints struct looks like: + * + * struct xdp_hints { + * u64 rx_timestamp; + * u64 tx_timestamp; + * u64 valid_map; + * u32 btf_id; + * }; + */ + +/* New fields need to be added at the beginning, not at the end, + * as the known position on the metadata is the end (just before + * the data starts) */ + +#define XDP_GENERIC_HINTS_STRUCT_MEMBERS \ + u64 rx_timestamp; \ + u64 tx_timestamp; \ + u64 valid_map; \ + u32 btf_id; + +#define BTF_INFO_ENC(kind, kind_flag, vlen) \ + ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN)) + +#define BTF_TYPE_ENC(name, info, size_or_type) \ + (name), (info), (size_or_type) + +#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \ + ((encoding) << 24 | (bits_offset) << 16 | (nr_bits)) + +#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \ + BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \ + BTF_INT_ENC(encoding, bits_offset, bits) + +#define BTF_STRUCT_ENC(name, nr_elems, sz) \ + BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_STRUCT, 1, nr_elems), sz) + +#define BTF_MEMBER_ENC(name, type, bits_offset) \ + (name), (type), (bits_offset) + +#define XDP_GENERIC_MD_SUPPORTED_HINTS_NUM_MMBRS 4 +#define XDP_GENERIC_HINTS_NAME_OFFSET 62 + +#define XDP_GENERIC_HINTS_NAMES "\0xdp_hints\0u32\0u64\0rx_timestamp\0" \ + "tx_timestamp\0valid_map\0btf_id\0" + +#define XDP_GENERIC_HINTS_TYPES \ + BTF_TYPE_INT_ENC(15, 0, 0, 64, 8), \ + BTF_TYPE_INT_ENC(11, 0, 0, 32, 4) + +#define XDP_GENERIC_HINTS_STRUCT(nr_elems, sz) \ + BTF_STRUCT_ENC(1, XDP_GENERIC_MD_SUPPORTED_HINTS_NUM_MMBRS + nr_elems, \ + 8 + 8 + 8 + 4 + sz) + +#define XDP_GENERIC_HINTS_MEMBERS(offset) \ + BTF_MEMBER_ENC(19, 1, offset + 0), \ + BTF_MEMBER_ENC(32, 1, offset + 64), \ + BTF_MEMBER_ENC(45, 1, offset + 128), \ + BTF_MEMBER_ENC(55, 2, offset + 192) + +#define XDP_GENERIC_HINTS_BIT_MAX XDP_GENERIC_HINTS_TX_TIMESTAMP + static __always_inline void xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq) {
diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
index a78a8096f4ce..345c757b8c3e 100644
--- a/include/uapi/linux/if_xdp.h
+++ b/include/uapi/linux/if_xdp.h@@ -12,6 +12,9 @@ #include <linux/types.h> +#define XDP_GENERIC_HINTS_RX_TIMESTAMP (1 << 0) +#define XDP_GENERIC_HINTS_TX_TIMESTAMP (1 << 1) + /* Options for the sxdp_flags field */ #define XDP_SHARED_UMEM (1 << 0) #define XDP_COPY (1 << 1) /* Force copy-mode */
--
2.32.0