vdpa/mlx5: Add debugfs subtree

Add debugfs subtree and expose flow table ID and TIR number. This
information can be used by external tools to do extended
troubleshooting.

The information can be retrieved like so:
$ cat /sys/kernel/debug/mlx5/mlx5_core.sf.1/vdpa-0/rx/table_id
$ cat /sys/kernel/debug/mlx5/mlx5_core.sf.1/vdpa-0/rx/tirn

Reviewed-by: Si-Wei Liu <si-wei.liu@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eli Cohen <elic@nvidia.com>
Message-Id: <20221114131759.57883-8-elic@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/mlx5/Makefile

@@ -1,4 +1,4 @@
 subdir-ccflags-y += -I$(srctree)/drivers/vdpa/mlx5/core
 
 obj-$(CONFIG_MLX5_VDPA_NET) += mlx5_vdpa.o
-mlx5_vdpa-$(CONFIG_MLX5_VDPA_NET) += net/mlx5_vnet.o core/resources.o core/mr.o
+mlx5_vdpa-$(CONFIG_MLX5_VDPA_NET) += net/mlx5_vnet.o core/resources.o core/mr.o net/debug.o

drivers/vdpa/mlx5/net/debug.c

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/* Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved. */
+
+#include <linux/debugfs.h>
+#include <linux/mlx5/fs.h>
+#include "mlx5_vnet.h"
+
+static int tirn_show(struct seq_file *file, void *priv)
+{
+	struct mlx5_vdpa_net *ndev = file->private;
+
+	seq_printf(file, "0x%x\n", ndev->res.tirn);
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(tirn);
+
+void mlx5_vdpa_remove_tirn(struct mlx5_vdpa_net *ndev)
+{
+	if (ndev->debugfs)
+		debugfs_remove(ndev->res.tirn_dent);
+}
+
+void mlx5_vdpa_add_tirn(struct mlx5_vdpa_net *ndev)
+{
+	ndev->res.tirn_dent = debugfs_create_file("tirn", 0444, ndev->rx_dent,
+						  ndev, &tirn_fops);
+}
+
+static int rx_flow_table_show(struct seq_file *file, void *priv)
+{
+	struct mlx5_vdpa_net *ndev = file->private;
+
+	seq_printf(file, "0x%x\n", mlx5_flow_table_id(ndev->rxft));
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(rx_flow_table);
+
+void mlx5_vdpa_remove_rx_flow_table(struct mlx5_vdpa_net *ndev)
+{
+	if (ndev->debugfs)
+		debugfs_remove(ndev->rx_table_dent);
+}
+
+void mlx5_vdpa_add_rx_flow_table(struct mlx5_vdpa_net *ndev)
+{
+	ndev->rx_table_dent = debugfs_create_file("table_id", 0444, ndev->rx_dent,
+						  ndev, &rx_flow_table_fops);
+}
+
+void mlx5_vdpa_add_debugfs(struct mlx5_vdpa_net *ndev)
+{
+	struct mlx5_core_dev *mdev;
+
+	mdev = ndev->mvdev.mdev;
+	ndev->debugfs = debugfs_create_dir(dev_name(&ndev->mvdev.vdev.dev),
+					   mlx5_debugfs_get_dev_root(mdev));
+	if (!IS_ERR(ndev->debugfs))
+		ndev->rx_dent = debugfs_create_dir("rx", ndev->debugfs);
+}
+
+void mlx5_vdpa_remove_debugfs(struct dentry *dbg)
+{
+	debugfs_remove_recursive(dbg);
+}

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -1388,11 +1388,16 @@ static int create_tir(struct mlx5_vdpa_net *ndev)
 
 	err = mlx5_vdpa_create_tir(&ndev->mvdev, in, &ndev->res.tirn);
 	kfree(in);
+	if (err)
+		return err;
+
+	mlx5_vdpa_add_tirn(ndev);
 	return err;
 }
 
 static void destroy_tir(struct mlx5_vdpa_net *ndev)
 {
+	mlx5_vdpa_remove_tirn(ndev);
 	mlx5_vdpa_destroy_tir(&ndev->mvdev, ndev->res.tirn);
 }
 
@@ -1578,6 +1583,7 @@ static int setup_steering(struct mlx5_vdpa_net *ndev)
 		mlx5_vdpa_warn(&ndev->mvdev, "failed to create flow table\n");
 		return PTR_ERR(ndev->rxft);
 	}
+	mlx5_vdpa_add_rx_flow_table(ndev);
 
 	err = mac_vlan_add(ndev, ndev->config.mac, 0, false);
 	if (err)
@@ -1586,6 +1592,7 @@ static int setup_steering(struct mlx5_vdpa_net *ndev)
 	return 0;
 
 err_add:
+	mlx5_vdpa_remove_rx_flow_table(ndev);
 	mlx5_destroy_flow_table(ndev->rxft);
 	return err;
 }
@@ -1593,6 +1600,7 @@ err_add:
 static void teardown_steering(struct mlx5_vdpa_net *ndev)
 {
 	clear_mac_vlan_table(ndev);
+	mlx5_vdpa_remove_rx_flow_table(ndev);
 	mlx5_destroy_flow_table(ndev->rxft);
 }
 
@@ -3135,6 +3143,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
 	if (err)
 		goto err_reg;
 
+	mlx5_vdpa_add_debugfs(ndev);
 	mgtdev->ndev = ndev;
 	return 0;
 
@@ -3161,6 +3170,8 @@ static void mlx5_vdpa_dev_del(struct vdpa_mgmt_dev *v_mdev, struct vdpa_device *
 	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
 	struct workqueue_struct *wq;
 
+	mlx5_vdpa_remove_debugfs(ndev->debugfs);
+	ndev->debugfs = NULL;
 	if (ndev->nb_registered) {
 		ndev->nb_registered = false;
 		mlx5_notifier_unregister(mvdev->mdev, &ndev->nb);

drivers/vdpa/mlx5/net/mlx5_vnet.h

@@ -16,6 +16,7 @@ struct mlx5_vdpa_net_resources {
 	u32 tirn;
 	u32 rqtn;
 	bool valid;
+	struct dentry *tirn_dent;
 };
 
 #define MLX5V_MACVLAN_SIZE 256
@@ -43,6 +44,7 @@ struct mlx5_vdpa_net {
 	struct vdpa_callback config_cb;
 	struct mlx5_vdpa_wq_ent cvq_ent;
 	struct hlist_head macvlan_hash[MLX5V_MACVLAN_SIZE];
+	struct dentry *debugfs;
 };
 
 struct macvlan_node {
@@ -52,4 +54,11 @@ struct macvlan_node {
 	u64 macvlan;
 };
 
+void mlx5_vdpa_add_debugfs(struct mlx5_vdpa_net *ndev);
+void mlx5_vdpa_remove_debugfs(struct dentry *dbg);
+void mlx5_vdpa_add_rx_flow_table(struct mlx5_vdpa_net *ndev);
+void mlx5_vdpa_remove_rx_flow_table(struct mlx5_vdpa_net *ndev);
+void mlx5_vdpa_add_tirn(struct mlx5_vdpa_net *ndev);
+void mlx5_vdpa_remove_tirn(struct mlx5_vdpa_net *ndev);
+
 #endif /* __MLX5_VNET_H__ */