diff options
author | Stanislav Fomichev <sdf@google.com> | 2023-11-27 22:03:08 +0300 |
---|---|---|
committer | Alexei Starovoitov <ast@kernel.org> | 2023-11-30 01:59:40 +0300 |
commit | 48eb03dd26304c24f03bdbb9382e89c8564e71df (patch) | |
tree | ac572d4d71fa6012c7267efc03d17c18bcb11e5c /include | |
parent | 341ac980eab90ac1f6c22ee9f9da83ed9604d899 (diff) | |
download | linux-48eb03dd26304c24f03bdbb9382e89c8564e71df.tar.xz |
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 <yoong.siang.song@intel.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20231127190319.1190813-3-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/netdevice.h | 2 | ||||
-rw-r--r-- | include/linux/skbuff.h | 14 | ||||
-rw-r--r-- | include/net/xdp_sock.h | 110 | ||||
-rw-r--r-- | include/net/xdp_sock_drv.h | 13 | ||||
-rw-r--r-- | include/net/xsk_buff_pool.h | 6 | ||||
-rw-r--r-- | include/uapi/linux/if_xdp.h | 38 | ||||
-rw-r--r-- | include/uapi/linux/netdev.h | 16 |
7 files changed, 198 insertions, 1 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index e87caa81f70c..08da8b28c816 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1865,6 +1865,7 @@ enum netdev_stat_type { * @netdev_ops: Includes several pointers to callbacks, * if one wants to override the ndo_*() functions * @xdp_metadata_ops: Includes pointers to XDP metadata callbacks. + * @xsk_tx_metadata_ops: Includes pointers to AF_XDP TX metadata callbacks. * @ethtool_ops: Management operations * @l3mdev_ops: Layer 3 master device operations * @ndisc_ops: Includes callbacks for different IPv6 neighbour @@ -2128,6 +2129,7 @@ struct net_device { unsigned long long priv_flags; const struct net_device_ops *netdev_ops; const struct xdp_metadata_ops *xdp_metadata_ops; + const struct xsk_tx_metadata_ops *xsk_tx_metadata_ops; int ifindex; unsigned short gflags; unsigned short hard_header_len; diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 27998f73183e..b370eb8d70f7 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -566,6 +566,15 @@ struct ubuf_info_msgzc { int mm_account_pinned_pages(struct mmpin *mmp, size_t size); void mm_unaccount_pinned_pages(struct mmpin *mmp); +/* Preserve some data across TX submission and completion. + * + * Note, this state is stored in the driver. Extending the layout + * might need some special care. + */ +struct xsk_tx_metadata_compl { + __u64 *tx_timestamp; +}; + /* This data is invariant across clones and lives at * the end of the header data, ie. at skb->end. */ @@ -578,7 +587,10 @@ struct skb_shared_info { /* Warning: this field is not always filled in (UFO)! */ unsigned short gso_segs; struct sk_buff *frag_list; - struct skb_shared_hwtstamps hwtstamps; + union { + struct skb_shared_hwtstamps hwtstamps; + struct xsk_tx_metadata_compl xsk_meta; + }; unsigned int gso_type; u32 tskey; diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h index bcf765124f72..3cb4dc9bd70e 100644 --- a/include/net/xdp_sock.h +++ b/include/net/xdp_sock.h @@ -93,12 +93,105 @@ struct xdp_sock { struct xsk_queue *cq_tmp; /* Only as tmp storage before bind */ }; +/* + * AF_XDP TX metadata hooks for network devices. + * The following hooks can be defined; unless noted otherwise, they are + * optional and can be filled with a null pointer. + * + * void (*tmo_request_timestamp)(void *priv) + * Called when AF_XDP frame requested egress timestamp. + * + * u64 (*tmo_fill_timestamp)(void *priv) + * Called when AF_XDP frame, that had requested egress timestamp, + * received a completion. The hook needs to return the actual HW timestamp. + * + * void (*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void *priv) + * Called when AF_XDP frame requested HW checksum offload. csum_start + * indicates position where checksumming should start. + * csum_offset indicates position where checksum should be stored. + * + */ +struct xsk_tx_metadata_ops { + void (*tmo_request_timestamp)(void *priv); + u64 (*tmo_fill_timestamp)(void *priv); + void (*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void *priv); +}; + #ifdef CONFIG_XDP_SOCKETS int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp); int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp); void __xsk_map_flush(void); +/** + * xsk_tx_metadata_to_compl - Save enough relevant metadata information + * to perform tx completion in the future. + * @meta: pointer to AF_XDP metadata area + * @compl: pointer to output struct xsk_tx_metadata_to_compl + * + * This function should be called by the networking device when + * it prepares AF_XDP egress packet. The value of @compl should be stored + * and passed to xsk_tx_metadata_complete upon TX completion. + */ +static inline void xsk_tx_metadata_to_compl(struct xsk_tx_metadata *meta, + struct xsk_tx_metadata_compl *compl) +{ + if (!meta) + return; + + if (meta->flags & XDP_TXMD_FLAGS_TIMESTAMP) + compl->tx_timestamp = &meta->completion.tx_timestamp; + else + compl->tx_timestamp = NULL; +} + +/** + * xsk_tx_metadata_request - Evaluate AF_XDP TX metadata at submission + * and call appropriate xsk_tx_metadata_ops operation. + * @meta: pointer to AF_XDP metadata area + * @ops: pointer to struct xsk_tx_metadata_ops + * @priv: pointer to driver-private aread + * + * This function should be called by the networking device when + * it prepares AF_XDP egress packet. + */ +static inline void xsk_tx_metadata_request(const struct xsk_tx_metadata *meta, + const struct xsk_tx_metadata_ops *ops, + void *priv) +{ + if (!meta) + return; + + if (ops->tmo_request_timestamp) + if (meta->flags & XDP_TXMD_FLAGS_TIMESTAMP) + ops->tmo_request_timestamp(priv); + + if (ops->tmo_request_checksum) + if (meta->flags & XDP_TXMD_FLAGS_CHECKSUM) + ops->tmo_request_checksum(meta->request.csum_start, + meta->request.csum_offset, priv); +} + +/** + * xsk_tx_metadata_complete - Evaluate AF_XDP TX metadata at completion + * and call appropriate xsk_tx_metadata_ops operation. + * @compl: pointer to completion metadata produced from xsk_tx_metadata_to_compl + * @ops: pointer to struct xsk_tx_metadata_ops + * @priv: pointer to driver-private aread + * + * This function should be called by the networking device upon + * AF_XDP egress completion. + */ +static inline void xsk_tx_metadata_complete(struct xsk_tx_metadata_compl *compl, + const struct xsk_tx_metadata_ops *ops, + void *priv) +{ + if (!compl) + return; + + *compl->tx_timestamp = ops->tmo_fill_timestamp(priv); +} + #else static inline int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp) @@ -115,6 +208,23 @@ static inline void __xsk_map_flush(void) { } +static inline void xsk_tx_metadata_to_compl(struct xsk_tx_metadata *meta, + struct xsk_tx_metadata_compl *compl) +{ +} + +static inline void xsk_tx_metadata_request(struct xsk_tx_metadata *meta, + const struct xsk_tx_metadata_ops *ops, + void *priv) +{ +} + +static inline void xsk_tx_metadata_complete(struct xsk_tx_metadata_compl *compl, + const struct xsk_tx_metadata_ops *ops, + void *priv) +{ +} + #endif /* CONFIG_XDP_SOCKETS */ #if defined(CONFIG_XDP_SOCKETS) && defined(CONFIG_DEBUG_NET) diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h index 1f6fc8c7a84c..e2558ac3e195 100644 --- a/include/net/xdp_sock_drv.h +++ b/include/net/xdp_sock_drv.h @@ -165,6 +165,14 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr) return xp_raw_get_data(pool, addr); } +static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool *pool, u64 addr) +{ + if (!pool->tx_metadata_len) + return NULL; + + return xp_raw_get_data(pool, addr) - pool->tx_metadata_len; +} + static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct xsk_buff_pool *pool) { struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp); @@ -324,6 +332,11 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr) return NULL; } +static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool *pool, u64 addr) +{ + return NULL; +} + static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct xsk_buff_pool *pool) { } 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_ */ diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h index 2ecf79282c26..95de66d5a26c 100644 --- a/include/uapi/linux/if_xdp.h +++ b/include/uapi/linux/if_xdp.h @@ -106,6 +106,41 @@ struct xdp_options { #define XSK_UNALIGNED_BUF_ADDR_MASK \ ((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1) +/* Request transmit timestamp. Upon completion, put it into tx_timestamp + * field of struct xsk_tx_metadata. + */ +#define XDP_TXMD_FLAGS_TIMESTAMP (1 << 0) + +/* Request transmit checksum offload. Checksum start position and offset + * are communicated via csum_start and csum_offset fields of struct + * xsk_tx_metadata. + */ +#define XDP_TXMD_FLAGS_CHECKSUM (1 << 1) + +/* AF_XDP offloads request. 'request' union member is consumed by the driver + * when the packet is being transmitted. 'completion' union member is + * filled by the driver when the transmit completion arrives. + */ +struct xsk_tx_metadata { + __u64 flags; + + union { + struct { + /* XDP_TXMD_FLAGS_CHECKSUM */ + + /* Offset from desc->addr where checksumming should start. */ + __u16 csum_start; + /* Offset from csum_start where checksum should be stored. */ + __u16 csum_offset; + } request; + + struct { + /* XDP_TXMD_FLAGS_TIMESTAMP */ + __u64 tx_timestamp; + } completion; + }; +}; + /* Rx/Tx descriptor */ struct xdp_desc { __u64 addr; @@ -122,4 +157,7 @@ struct xdp_desc { */ #define XDP_PKT_CONTD (1 << 0) +/* TX packet carries valid metadata. */ +#define XDP_TX_METADATA (1 << 1) + #endif /* _LINUX_IF_XDP_H */ diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h index 2943a151d4f1..48d5477a668c 100644 --- a/include/uapi/linux/netdev.h +++ b/include/uapi/linux/netdev.h @@ -53,12 +53,28 @@ enum netdev_xdp_rx_metadata { NETDEV_XDP_RX_METADATA_MASK = 3, }; +/** + * enum netdev_xsk_flags + * @NETDEV_XSK_FLAGS_TX_TIMESTAMP: HW timestamping egress packets is supported + * by the driver. + * @NETDEV_XSK_FLAGS_TX_CHECKSUM: L3 checksum HW offload is supported by the + * driver. + */ +enum netdev_xsk_flags { + NETDEV_XSK_FLAGS_TX_TIMESTAMP = 1, + NETDEV_XSK_FLAGS_TX_CHECKSUM = 2, + + /* private: */ + NETDEV_XSK_FLAGS_MASK = 3, +}; + enum { NETDEV_A_DEV_IFINDEX = 1, NETDEV_A_DEV_PAD, NETDEV_A_DEV_XDP_FEATURES, NETDEV_A_DEV_XDP_ZC_MAX_SEGS, NETDEV_A_DEV_XDP_RX_METADATA_FEATURES, + NETDEV_A_DEV_XSK_FEATURES, __NETDEV_A_DEV_MAX, NETDEV_A_DEV_MAX = (__NETDEV_A_DEV_MAX - 1) |