From 6f377873cb23905009759b7366b9fe85c2a6ff37 Mon Sep 17 00:00:00 2001 From: David Wei Date: Fri, 14 Feb 2025 16:09:36 -0800 Subject: io_uring/zcrx: add interface queue and refill queue Add a new object called an interface queue (ifq) that represents a net rx queue that has been configured for zero copy. Each ifq is registered using a new registration opcode IORING_REGISTER_ZCRX_IFQ. The refill queue is allocated by the kernel and mapped by userspace using a new offset IORING_OFF_RQ_RING, in a similar fashion to the main SQ/CQ. It is used by userspace to return buffers that it is done with, which will then be re-used by the netdev again. The main CQ ring is used to notify userspace of received data by using the upper 16 bytes of a big CQE as a new struct io_uring_zcrx_cqe. Each entry contains the offset + len to the data. For now, each io_uring instance only has a single ifq. Reviewed-by: Jens Axboe Signed-off-by: David Wei Acked-by: Jakub Kicinski Link: https://lore.kernel.org/r/20250215000947.789731-2-dw@davidwei.uk Signed-off-by: Jens Axboe --- include/uapi/linux/io_uring.h | 43 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 42 insertions(+), 1 deletion(-) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index e11c82638527..6a1632d0fba1 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -639,7 +639,8 @@ enum io_uring_register_op { /* send MSG_RING without having a ring */ IORING_REGISTER_SEND_MSG_RING = 31, - /* 32 reserved for zc rx */ + /* register a netdev hw rx queue for zerocopy */ + IORING_REGISTER_ZCRX_IFQ = 32, /* resize CQ ring */ IORING_REGISTER_RESIZE_RINGS = 33, @@ -956,6 +957,46 @@ enum io_uring_socket_op { SOCKET_URING_OP_SETSOCKOPT, }; +/* Zero copy receive refill queue entry */ +struct io_uring_zcrx_rqe { + __u64 off; + __u32 len; + __u32 __pad; +}; + +struct io_uring_zcrx_cqe { + __u64 off; + __u64 __pad; +}; + +/* The bit from which area id is encoded into offsets */ +#define IORING_ZCRX_AREA_SHIFT 48 +#define IORING_ZCRX_AREA_MASK (~(((__u64)1 << IORING_ZCRX_AREA_SHIFT) - 1)) + +struct io_uring_zcrx_offsets { + __u32 head; + __u32 tail; + __u32 rqes; + __u32 __resv2; + __u64 __resv[2]; +}; + +/* + * Argument for IORING_REGISTER_ZCRX_IFQ + */ +struct io_uring_zcrx_ifq_reg { + __u32 if_idx; + __u32 if_rxq; + __u32 rq_entries; + __u32 flags; + + __u64 area_ptr; /* pointer to struct io_uring_zcrx_area_reg */ + __u64 region_ptr; /* struct io_uring_region_desc * */ + + struct io_uring_zcrx_offsets offsets; + __u64 __resv[4]; +}; + #ifdef __cplusplus } #endif -- cgit v1.2.3