[PATCH liburing 1/3] Update uapi headers to add ZCRX notification

["Clément Léger" <cleger@meta.com>]

Extend the ZCRX uapi with notification infrastructure: notification
types (no-buffers, copy-fallback), stats structure, notification
descriptor for registration and arm control operation.

A new IORING_REGISTER_QUERY op allows userspace to discover the
notification stats memory layout. Additionnal flags are as well required
to register the statistics structure and enable notification upon
registration.

Signed-off-by: Clément Léger <cleger@meta.com>
---
 src/include/liburing/io_uring.h       | 34 ++++++++++++++++++++++++++-
 src/include/liburing/io_uring/query.h | 12 ++++++++++
 2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
index 983aa265..a479d0b5 100644
--- a/src/include/liburing/io_uring.h
+++ b/src/include/liburing/io_uring.h
@@ -1068,6 +1068,30 @@ enum zcrx_features {
 	 * value in struct io_uring_zcrx_ifq_reg::rx_buf_len.
 	 */
 	ZCRX_FEATURE_RX_PAGE_SIZE	= 1 << 0,
+	ZCRX_FEATURE_NOTIFICATION	= 1 << 1,
+};
+
+enum zcrx_notification_type {
+	ZCRX_NOTIF_NO_BUFFERS = 1 << 0,
+	ZCRX_NOTIF_COPY = 1 << 1
+};
+
+enum zcrx_notification_desc_flags {
+	/* If set, assume that stats_offset hold a correct offset to  */
+	ZCRX_NOTIF_DESC_FLAG_STATS = 1 << 0,
+};
+
+struct io_uring_zcrx_notif_stats {
+	__u64	copy_count;	/* cumulative copy-fallback CQEs */
+	__u64	copy_bytes;	/* cumulative bytes copied */
+};
+
+struct zcrx_notification_desc {
+	__u64	user_data;
+	__u32	type_mask;
+	__u32	flags; /* see enum zcrx_notification_desc_flags */
+	__u64	stats_offset; /* offset from the beginning of refill ring region for stats */
+	__u64	__resv2[9];
 };
 
 /*
@@ -1085,12 +1109,14 @@ struct io_uring_zcrx_ifq_reg {
 	struct io_uring_zcrx_offsets offsets;
 	__u32	zcrx_id;
 	__u32	rx_buf_len;
-	__u64	__resv[3];
+	__u64	notif_desc; /* see struct zcrx_notification_desc */
+	__u64	__resv[2];
 };
 
 enum zcrx_ctrl_op {
 	ZCRX_CTRL_FLUSH_RQ,
 	ZCRX_CTRL_EXPORT,
+	ZCRX_CTRL_ARM_NOTIFICATION,
 
 	__ZCRX_CTRL_LAST,
 };
@@ -1104,6 +1130,11 @@ struct zcrx_ctrl_export {
 	__u32 		__resv1[11];
 };
 
+struct zcrx_ctrl_arm_notif {
+	__u32		type_mask;
+	__u32		__resv[11];
+};
+
 struct zcrx_ctrl {
 	__u32	zcrx_id;
 	__u32	op; /* see enum zcrx_ctrl_op */
@@ -1112,6 +1143,7 @@ struct zcrx_ctrl {
 	union {
 		struct zcrx_ctrl_export		zc_export;
 		struct zcrx_ctrl_flush_rq	zc_flush;
+		struct zcrx_ctrl_arm_notif	zc_arm_notif;
 	};
 };
 
diff --git a/src/include/liburing/io_uring/query.h b/src/include/liburing/io_uring/query.h
index 0b624817..ad5efd99 100644
--- a/src/include/liburing/io_uring/query.h
+++ b/src/include/liburing/io_uring/query.h
@@ -20,6 +20,7 @@ enum {
 	IO_URING_QUERY_OPCODES			= 0,
 	IO_URING_QUERY_ZCRX			= 1,
 	IO_URING_QUERY_SCQ			= 2,
+	IO_URING_QUERY_ZCRX_NOTIF		= 3,
 
 	__IO_URING_QUERY_MAX,
 };
@@ -59,6 +60,17 @@ struct io_uring_query_zcrx {
 	__u64 __resv2;
 };
 
+struct io_uring_query_zcrx_notif {
+	/* Bitmask of supported ZCRX_NOTIF_* flags*/
+	__u32 notif_flags;
+	/* Size of io_uring_zcrx_notif_stats */
+	__u32 notif_stats_size;
+	/* Required alignment for the stats buffer within the region (ie stats_offset) */
+	__u32 notif_stats_off_alignment;
+	__u32 resv1;
+	__u64 __resv2[10];
+};
+
 struct io_uring_query_scq {
 	/* The SQ/CQ rings header size */
 	__u64 hdr_size;
-- 
2.52.0