mlx5: Implement the import/unimport PD verbs

Implement the import/unimport PD verbs based on their definition as
described in the man page.

It uses the query PD ioctl command to retrieve the original PD
properties based on its given handle.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>

providers/mlx5/mlx5.c

@@ -144,6 +144,7 @@ static const struct verbs_context_ops mlx5_ctx_common_ops = {
 	.destroy_wq = mlx5_destroy_wq,
 	.free_dm = mlx5_free_dm,
 	.get_srq_num = mlx5_get_srq_num,
+	.import_pd = mlx5_import_pd,
 	.modify_cq = mlx5_modify_cq,
 	.modify_flow_action_esp = mlx5_modify_flow_action_esp,
 	.modify_qp_rate_limit = mlx5_modify_qp_rate_limit,
@@ -159,6 +160,7 @@ static const struct verbs_context_ops mlx5_ctx_common_ops = {
 	.alloc_null_mr = mlx5_alloc_null_mr,
 	.free_context = mlx5_free_context,
 	.set_ece = mlx5_set_ece,
+	.unimport_pd = mlx5_unimport_pd,
 };
 
 static const struct verbs_context_ops mlx5_ctx_cqev1_ops = {

providers/mlx5/mlx5.h

@@ -1040,6 +1040,9 @@ int mlx5_advise_mr(struct ibv_pd *pd,
 		   uint32_t flags,
 		   struct ibv_sge *sg_list,
 		   uint32_t num_sges);
+struct ibv_pd *mlx5_import_pd(struct ibv_context *context,
+			      uint32_t pd_handle);
+void mlx5_unimport_pd(struct ibv_pd *pd);
 int mlx5_qp_fill_wr_pfns(struct mlx5_qp *mqp,
 			 const struct ibv_qp_init_attr_ex *attr,
 			 const struct mlx5dv_qp_init_attr *mlx5_attr);

providers/mlx5/verbs.c

@@ -556,26 +556,39 @@ static int mlx5_dealloc_parent_domain(struct mlx5_parent_domain *mparent_domain)
 	return 0;
 }
 
-int mlx5_free_pd(struct ibv_pd *pd)
+static int _mlx5_free_pd(struct ibv_pd *pd, bool unimport)
 {
 	int ret;
 	struct mlx5_parent_domain *mparent_domain = to_mparent_domain(pd);
 	struct mlx5_pd *mpd = to_mpd(pd);
 
-	if (mparent_domain)
+	if (mparent_domain) {
+		if (unimport)
+			return EINVAL;
+
 		return mlx5_dealloc_parent_domain(mparent_domain);
+	}
 
 	if (atomic_load(&mpd->refcount) > 1)
 		return EBUSY;
 
+	if (unimport)
+		goto end;
+
 	ret = ibv_cmd_dealloc_pd(pd);
 	if (ret)
 		return ret;
 
+end:
 	free(mpd);
 	return 0;
 }
 
+int mlx5_free_pd(struct ibv_pd *pd)
+{
+	return _mlx5_free_pd(pd, false);
+}
+
 struct ibv_mr *mlx5_reg_mr(struct ibv_pd *pd, void *addr, size_t length,
 			   uint64_t hca_va, int acc)
 {
@@ -706,6 +719,43 @@ int mlx5_advise_mr(struct ibv_pd *pd,
 	return ibv_cmd_advise_mr(pd, advice, flags, sg_list, num_sge);
 }
 
+struct ibv_pd *mlx5_import_pd(struct ibv_context *context,
+			      uint32_t pd_handle)
+{
+	DECLARE_COMMAND_BUFFER(cmd,
+			       UVERBS_OBJECT_PD,
+			       MLX5_IB_METHOD_PD_QUERY,
+			       2);
+
+	struct mlx5_pd *pd;
+	int ret;
+
+	pd = calloc(1, sizeof *pd);
+	if (!pd)
+		return NULL;
+
+	fill_attr_in_obj(cmd, MLX5_IB_ATTR_QUERY_PD_HANDLE, pd_handle);
+	fill_attr_out_ptr(cmd, MLX5_IB_ATTR_QUERY_PD_RESP_PDN, &pd->pdn);
+
+	ret = execute_ioctl(context, cmd);
+	if (ret) {
+		free(pd);
+		return NULL;
+	}
+
+	pd->ibv_pd.context = context;
+	pd->ibv_pd.handle = pd_handle;
+	atomic_init(&pd->refcount, 1);
+
+	return &pd->ibv_pd;
+}
+
+void mlx5_unimport_pd(struct ibv_pd *pd)
+{
+	if (_mlx5_free_pd(pd, true))
+		assert(false);
+}
+
 struct ibv_mw *mlx5_alloc_mw(struct ibv_pd *pd, enum ibv_mw_type type)
 {
 	struct ibv_mw *mw;