RDMA/mlx5: Create UCAP char devices for supported device capabilities

JIRA: https://issues.redhat.com/browse/RHEL-72227
JIRA: https://issues.redhat.com/browse/RHEL-73520
Upstream-status: v6.15-rc1

commit cf7174e
Author: Chiara Meiohas <cmeiohas@nvidia.com>
Date:   Thu Mar 6 13:51:27 2025 +0200

    RDMA/mlx5: Create UCAP char devices for supported device capabilities

    Create UCAP character devices when probing an IB device with supported
    firmware capabilities.

    If the RDMA_CTRL general object type is supported, check for specific
    UCTX capabilities:
    Create /dev/infiniband/mlx5_perm_ctrl_local for RDMA_UCAP_MLX5_CTRL_LOCAL
    Create /dev/infiniband/mlx5_perm_ctrl_other_vhca for RDMA_UCAP_MLX5_CTRL_OTHER_VHCA

    Signed-off-by: Chiara Meiohas <cmeiohas@nvidia.com>
    Link: https://patch.msgid.link/30ed40e7a12a694cf4ee257459ed61b145b7837d.1741261611.git.leon@kernel.org
    Reviewed-by: Yishai Hadas <yishaih@nvidia.com>
    Signed-off-by: Leon Romanovsky <leon@kernel.org>

Signed-off-by: Benjamin Poirier <bpoirier@redhat.com>

Author: Benjamin Poirier

drivers/infiniband/hw/mlx5/main.c

@@ -47,6 +47,7 @@
 #include <rdma/uverbs_ioctl.h>
 #include <rdma/mlx5_user_ioctl_verbs.h>
 #include <rdma/mlx5_user_ioctl_cmds.h>
+#include <rdma/ib_ucaps.h>
 #include "macsec.h"
 #include "data_direct.h"
 
@@ -4201,8 +4202,47 @@ static int mlx5_ib_init_var_table(struct mlx5_ib_dev *dev)
 	return (var_table->bitmap) ? 0 : -ENOMEM;
 }
 
+static void mlx5_ib_cleanup_ucaps(struct mlx5_ib_dev *dev)
+{
+	if (MLX5_CAP_GEN(dev->mdev, uctx_cap) & MLX5_UCTX_CAP_RDMA_CTRL)
+		ib_remove_ucap(RDMA_UCAP_MLX5_CTRL_LOCAL);
+
+	if (MLX5_CAP_GEN(dev->mdev, uctx_cap) &
+	    MLX5_UCTX_CAP_RDMA_CTRL_OTHER_VHCA)
+		ib_remove_ucap(RDMA_UCAP_MLX5_CTRL_OTHER_VHCA);
+}
+
+static int mlx5_ib_init_ucaps(struct mlx5_ib_dev *dev)
+{
+	int ret;
+
+	if (MLX5_CAP_GEN(dev->mdev, uctx_cap) & MLX5_UCTX_CAP_RDMA_CTRL) {
+		ret = ib_create_ucap(RDMA_UCAP_MLX5_CTRL_LOCAL);
+		if (ret)
+			return ret;
+	}
+
+	if (MLX5_CAP_GEN(dev->mdev, uctx_cap) &
+	    MLX5_UCTX_CAP_RDMA_CTRL_OTHER_VHCA) {
+		ret = ib_create_ucap(RDMA_UCAP_MLX5_CTRL_OTHER_VHCA);
+		if (ret)
+			goto remove_local;
+	}
+
+	return 0;
+
+remove_local:
+	if (MLX5_CAP_GEN(dev->mdev, uctx_cap) & MLX5_UCTX_CAP_RDMA_CTRL)
+		ib_remove_ucap(RDMA_UCAP_MLX5_CTRL_LOCAL);
+	return ret;
+}
+
 static void mlx5_ib_stage_caps_cleanup(struct mlx5_ib_dev *dev)
 {
+	if (MLX5_CAP_GEN_2_64(dev->mdev, general_obj_types_127_64) &
+	    MLX5_HCA_CAP_2_GENERAL_OBJECT_TYPES_RDMA_CTRL)
+		mlx5_ib_cleanup_ucaps(dev);
+
 	bitmap_free(dev->var_table.bitmap);
 }
 
@@ -4253,6 +4293,13 @@ static int mlx5_ib_stage_caps_init(struct mlx5_ib_dev *dev)
 			return err;
 	}
 
+	if (MLX5_CAP_GEN_2_64(dev->mdev, general_obj_types_127_64) &
+	    MLX5_HCA_CAP_2_GENERAL_OBJECT_TYPES_RDMA_CTRL) {
+		err = mlx5_ib_init_ucaps(dev);
+		if (err)
+			return err;
+	}
+
 	dev->ib_dev.use_cq_dim = true;
 
 	return 0;