From 48eb03dd26304c24f03bdbb9382e89c8564e71df Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Mon, 27 Nov 2023 11:03:08 -0800 Subject: xsk: Add TX timestamp and TX checksum offload support This change actually defines the (initial) metadata layout that should be used by AF_XDP userspace (xsk_tx_metadata). The first field is flags which requests appropriate offloads, followed by the offload-specific fields. The supported per-device offloads are exported via netlink (new xsk-flags). The offloads themselves are still implemented in a bit of a framework-y fashion that's left from my initial kfunc attempt. I'm introducing new xsk_tx_metadata_ops which drivers are supposed to implement. The drivers are also supposed to call xsk_tx_metadata_request/xsk_tx_metadata_complete in the right places. Since xsk_tx_metadata_{request,_complete} are static inline, we don't incur any extra overhead doing indirect calls. The benefit of this scheme is as follows: - keeps all metadata layout parsing away from driver code - makes it easy to grep and see which drivers implement what - don't need any extra flags to maintain to keep track of what offloads are implemented; if the callback is implemented - the offload is supported (used by netlink reporting code) Two offloads are defined right now: 1. XDP_TXMD_FLAGS_CHECKSUM: skb-style csum_start+csum_offset 2. XDP_TXMD_FLAGS_TIMESTAMP: writes TX timestamp back into metadata area upon completion (tx_timestamp field) XDP_TXMD_FLAGS_TIMESTAMP is also implemented for XDP_COPY mode: it writes SW timestamp from the skb destructor (note I'm reusing hwtstamps to pass metadata pointer). The struct is forward-compatible and can be extended in the future by appending more fields. Reviewed-by: Song Yoong Siang Signed-off-by: Stanislav Fomichev Acked-by: Jakub Kicinski Link: https://lore.kernel.org/r/20231127190319.1190813-3-sdf@google.com Signed-off-by: Alexei Starovoitov --- include/net/xsk_buff_pool.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/net/xsk_buff_pool.h') diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h index 1985ffaf9b0c..97f5cc10d79e 100644 --- a/include/net/xsk_buff_pool.h +++ b/include/net/xsk_buff_pool.h @@ -33,6 +33,7 @@ struct xdp_buff_xsk { }; #define XSK_CHECK_PRIV_TYPE(t) BUILD_BUG_ON(sizeof(t) > offsetofend(struct xdp_buff_xsk, cb)) +#define XSK_TX_COMPL_FITS(t) BUILD_BUG_ON(sizeof(struct xsk_tx_metadata_compl) > sizeof(t)) struct xsk_dma_map { dma_addr_t *dma_pages; @@ -234,4 +235,9 @@ static inline u64 xp_get_handle(struct xdp_buff_xsk *xskb) return xskb->orig_addr + (offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT); } +static inline bool xp_tx_metadata_enabled(const struct xsk_buff_pool *pool) +{ + return pool->tx_metadata_len > 0; +} + #endif /* XSK_BUFF_POOL_H_ */ -- cgit v1.2.3