git: 112ca55eefe8 - main - libmlx5: Extend mlx5dv_get_qp() to return UAR mapping info

The branch main has been updated by kib:

URL: https://cgit.FreeBSD.org/src/commit/?id=112ca55eefe8462c86f7507bff52ae4eb6488c71

commit 112ca55eefe8462c86f7507bff52ae4eb6488c71
Author:     Vag Singh <vag.singh@oneconvergence.com>
AuthorDate: 2025-08-12 01:30:33 +0000
Commit:     Konstantin Belousov <kib@FreeBSD.org>
CommitDate: 2026-09-16 14:12:06 +0000

    libmlx5: Extend mlx5dv_get_qp() to return UAR mapping info
    
    [PATCH 02/31] FreeBSD OFED support for DPDK MLX5 PMD
    
    Extend mlx5dv_get_qp() to return UAR mapping info. This can allow a
    process to share its doorbell access with secondary process by re-mmap
    the UAR address on the device and make it accessible as a user space
    address.
    
    Differential revision:  https://reviews.freebsd.org/D32176
    MFC after:      1 month
---
 contrib/ofed/libmlx5/mlx5.c   | 27 +++++++++++++++++++++------
 contrib/ofed/libmlx5/mlx5.h   |  1 +
 contrib/ofed/libmlx5/mlx5dv.h |  5 +++++
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/contrib/ofed/libmlx5/mlx5.c b/contrib/ofed/libmlx5/mlx5.c
index 6fe6cf594c3b..56abaa965a6c 100644
--- a/contrib/ofed/libmlx5/mlx5.c
+++ b/contrib/ofed/libmlx5/mlx5.c
@@ -667,8 +667,8 @@ static int mlx5dv_get_qp(struct ibv_qp *qp_in,
 			 struct mlx5dv_qp *qp_out)
 {
 	struct mlx5_qp *mqp = to_mqp(qp_in);
+	uint64_t mask_out = 0;
 
-	qp_out->comp_mask = 0;
 	qp_out->dbrec     = mqp->db;
 
 	if (mqp->sq_buf_size)
@@ -683,13 +683,20 @@ static int mlx5dv_get_qp(struct ibv_qp *qp_in,
 	qp_out->rq.wqe_cnt = mqp->rq.wqe_cnt;
 	qp_out->rq.stride  = 1 << mqp->rq.wqe_shift;
 
-	qp_out->bf.reg    = mqp->bf->reg;
+	qp_out->bf.reg     = mqp->bf->reg;
+
+	if (qp_out->comp_mask & MLX5DV_QP_MASK_UAR_MMAP_OFFSET) {
+		qp_out->uar_mmap_offset = mqp->bf->uar_mmap_offset;
+		mask_out |= MLX5DV_QP_MASK_UAR_MMAP_OFFSET;
+	}
 
 	if (mqp->bf->uuarn > 0)
 		qp_out->bf.size = mqp->bf->buf_size;
 	else
 		qp_out->bf.size = 0;
 
+	qp_out->comp_mask = mask_out;
+
 	return 0;
 }
 
@@ -774,6 +781,15 @@ static void adjust_uar_info(struct mlx5_device *mdev,
 	context->num_uars_per_page = resp.num_uars_per_page;
 }
 
+static off_t get_uar_mmap_offset(int idx, int page_size)
+{
+	off_t offset = 0;
+
+	set_command(MLX5_MMAP_GET_REGULAR_PAGES_CMD, &offset);
+	set_index(idx, &offset);
+	return offset * page_size;
+}
+
 static int mlx5_init_context(struct verbs_device *vdev,
 			     struct ibv_context *ctx, int cmd_fd)
 {
@@ -889,11 +905,9 @@ static int mlx5_init_context(struct verbs_device *vdev,
 
 	num_sys_page_map = context->tot_uuars / (context->num_uars_per_page * MLX5_NUM_NON_FP_BFREGS_PER_UAR);
 	for (i = 0; i < num_sys_page_map; ++i) {
-		offset = 0;
-		set_command(MLX5_MMAP_GET_REGULAR_PAGES_CMD, &offset);
-		set_index(i, &offset);
+		offset = get_uar_mmap_offset(i, page_size);
 		context->uar[i] = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED,
-				       cmd_fd, page_size * offset);
+				       cmd_fd, offset);
 		if (context->uar[i] == MAP_FAILED) {
 			context->uar[i] = NULL;
 			goto err_db_list_mutex;
@@ -913,6 +927,7 @@ static int mlx5_init_context(struct verbs_device *vdev,
 				if (bfi)
 					context->bfs[bfi].buf_size = context->bf_reg_size / 2;
 				context->bfs[bfi].uuarn = bfi;
+				context->bfs[bfi].uar_mmap_offset = get_uar_mmap_offset(i, page_size);
 			}
 		}
 	}
diff --git a/contrib/ofed/libmlx5/mlx5.h b/contrib/ofed/libmlx5/mlx5.h
index 456b9ba6db21..74c6685a1e73 100644
--- a/contrib/ofed/libmlx5/mlx5.h
+++ b/contrib/ofed/libmlx5/mlx5.h
@@ -386,6 +386,7 @@ struct mlx5_bf {
 	unsigned			offset;
 	unsigned			buf_size;
 	unsigned			uuarn;
+	off_t				uar_mmap_offset;
 };
 
 struct mlx5_mr {
diff --git a/contrib/ofed/libmlx5/mlx5dv.h b/contrib/ofed/libmlx5/mlx5dv.h
index 5cd0b0d95161..52d8803fb3ab 100644
--- a/contrib/ofed/libmlx5/mlx5dv.h
+++ b/contrib/ofed/libmlx5/mlx5dv.h
@@ -106,6 +106,10 @@ struct ibv_cq_ex *mlx5dv_create_cq(struct ibv_context *context,
 int mlx5dv_query_device(struct ibv_context *ctx_in,
 			struct mlx5dv_context *attrs_out);
 
+enum mlx5dv_qp_comp_mask {
+	MLX5DV_QP_MASK_UAR_MMAP_OFFSET		= 1 << 0,
+};
+
 struct mlx5dv_qp {
 	uint32_t		*dbrec;
 	struct {
@@ -123,6 +127,7 @@ struct mlx5dv_qp {
 		uint32_t	size;
 	} bf;
 	uint64_t		comp_mask;
+	off_t			uar_mmap_offset;
 };
 
 struct mlx5dv_cq {