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 --- Documentation/netlink/specs/netdev.yaml | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'Documentation/netlink') diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml index 14511b13f305..00439bcbd2e3 100644 --- a/Documentation/netlink/specs/netdev.yaml +++ b/Documentation/netlink/specs/netdev.yaml @@ -45,7 +45,6 @@ definitions: - type: flags name: xdp-rx-metadata - render-max: true entries: - name: timestamp @@ -55,6 +54,18 @@ definitions: name: hash doc: Device is capable of exposing receive packet hash via bpf_xdp_metadata_rx_hash(). + - + type: flags + name: xsk-flags + entries: + - + name: tx-timestamp + doc: + HW timestamping egress packets is supported by the driver. + - + name: tx-checksum + doc: + L3 checksum HW offload is supported by the driver. attribute-sets: - @@ -86,6 +97,11 @@ attribute-sets: See Documentation/networking/xdp-rx-metadata.rst for more details. type: u64 enum: xdp-rx-metadata + - + name: xsk-features + doc: Bitmask of enabled AF_XDP features. + type: u64 + enum: xsk-flags operations: list: @@ -103,6 +119,7 @@ operations: - xdp-features - xdp-zc-max-segs - xdp-rx-metadata-features + - xsk-features dump: reply: *dev-all - -- cgit