[PATCH 3/4] vdpa/mlx5: Add debugfs subtree

[Eli Cohen <elic@nvidia.com>]

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

Signed-off-by: Eli Cohen <elic@nvidia.com>
---
 drivers/vdpa/mlx5/Makefile        |  2 +-
 drivers/vdpa/mlx5/net/debug.c     | 66 +++++++++++++++++++++++++++++++
 drivers/vdpa/mlx5/net/mlx5_vnet.c | 11 ++++++
 drivers/vdpa/mlx5/net/mlx5_vnet.h |  9 +++++
 4 files changed, 87 insertions(+), 1 deletion(-)
 create mode 100644 drivers/vdpa/mlx5/net/debug.c

diff --git a/drivers/vdpa/mlx5/Makefile b/drivers/vdpa/mlx5/Makefile
index f717978c83bf..e791394c33e3 100644
--- a/drivers/vdpa/mlx5/Makefile
+++ b/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
diff --git a/drivers/vdpa/mlx5/net/debug.c b/drivers/vdpa/mlx5/net/debug.c
new file mode 100644
index 000000000000..95e4801df211
--- /dev/null
+++ b/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);
+}
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 64fdb940380f..ee50da33e25b 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/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);
 }
 
@@ -1576,6 +1581,7 @@ 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)
@@ -1584,6 +1590,7 @@ 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;
 }
@@ -1591,6 +1598,7 @@ static int setup_steering(struct mlx5_vdpa_net *ndev)
 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);
 }
 
@@ -3167,6 +3175,7 @@ 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;
 
@@ -3193,6 +3202,8 @@ 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) {
 		mlx5_notifier_unregister(mvdev->mdev, &ndev->nb);
 		ndev->nb_registered = false;
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.h b/drivers/vdpa/mlx5/net/mlx5_vnet.h
index 6691c879a6ca..f2cef3925e5b 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.h
+++ b/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__ */
-- 
2.35.1