net/mlx5: Support enable_vnet devlink dev param

Enable user to disable VDPA net auxiliary device so that when it is not
required, user can disable it.

For example,

$ devlink dev param set pci/0000:06:00.0 \
              name enable_vnet value false cmode driverinit
$ devlink dev reload pci/0000:06:00.0

At this point devlink instance do not create auxiliary device
mlx5_core.vnet.2 for the VDPA net functionality.
Signed-off-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx5/core/dev.c

@@ -116,7 +116,7 @@ static bool is_eth_enabled(struct mlx5_core_dev *dev)
 	return err ? false : val.vbool;
 }
 
-static bool is_vnet_supported(struct mlx5_core_dev *dev)
+bool mlx5_vnet_supported(struct mlx5_core_dev *dev)
 {
 	if (!IS_ENABLED(CONFIG_MLX5_VDPA_NET))
 		return false;
@@ -138,6 +138,17 @@ static bool is_vnet_supported(struct mlx5_core_dev *dev)
 	return true;
 }
 
+static bool is_vnet_enabled(struct mlx5_core_dev *dev)
+{
+	union devlink_param_value val;
+	int err;
+
+	err = devlink_param_driverinit_value_get(priv_to_devlink(dev),
+						 DEVLINK_PARAM_GENERIC_ID_ENABLE_VNET,
+						 &val);
+	return err ? false : val.vbool;
+}
+
 static bool is_ib_rep_supported(struct mlx5_core_dev *dev)
 {
 	if (!IS_ENABLED(CONFIG_MLX5_INFINIBAND))
@@ -226,7 +237,8 @@ static const struct mlx5_adev_device {
 	bool (*is_enabled)(struct mlx5_core_dev *dev);
 } mlx5_adev_devices[] = {
 	[MLX5_INTERFACE_PROTOCOL_VNET] = { .suffix = "vnet",
-					   .is_supported = &is_vnet_supported },
+					   .is_supported = &mlx5_vnet_supported,
+					   .is_enabled = &is_vnet_enabled },
 	[MLX5_INTERFACE_PROTOCOL_IB] = { .suffix = "rdma",
 					 .is_supported = &mlx5_rdma_supported,
 					 .is_enabled = &is_ib_enabled },

drivers/net/ethernet/mellanox/mlx5/core/devlink.c

@@ -680,6 +680,42 @@ static void mlx5_devlink_rdma_param_unregister(struct devlink *devlink)
 	devlink_param_unregister(devlink, &enable_rdma_param);
 }
 
+static const struct devlink_param enable_vnet_param =
+	DEVLINK_PARAM_GENERIC(ENABLE_VNET, BIT(DEVLINK_PARAM_CMODE_DRIVERINIT),
+			      NULL, NULL, NULL);
+
+static int mlx5_devlink_vnet_param_register(struct devlink *devlink)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+	union devlink_param_value value;
+	int err;
+
+	if (!mlx5_vnet_supported(dev))
+		return 0;
+
+	err = devlink_param_register(devlink, &enable_vnet_param);
+	if (err)
+		return err;
+
+	value.vbool = true;
+	devlink_param_driverinit_value_set(devlink,
+					   DEVLINK_PARAM_GENERIC_ID_ENABLE_VNET,
+					   value);
+	devlink_param_publish(devlink, &enable_rdma_param);
+	return 0;
+}
+
+static void mlx5_devlink_vnet_param_unregister(struct devlink *devlink)
+{
+	struct mlx5_core_dev *dev = devlink_priv(devlink);
+
+	if (!mlx5_vnet_supported(dev))
+		return;
+
+	devlink_param_unpublish(devlink, &enable_vnet_param);
+	devlink_param_unregister(devlink, &enable_vnet_param);
+}
+
 static int mlx5_devlink_auxdev_params_register(struct devlink *devlink)
 {
 	int err;
@@ -692,8 +728,13 @@ static int mlx5_devlink_auxdev_params_register(struct devlink *devlink)
 	if (err)
 		goto rdma_err;
 
+	err = mlx5_devlink_vnet_param_register(devlink);
+	if (err)
+		goto vnet_err;
 	return 0;
 
+vnet_err:
+	mlx5_devlink_rdma_param_unregister(devlink);
 rdma_err:
 	mlx5_devlink_eth_param_unregister(devlink);
 	return err;
@@ -701,6 +742,7 @@ static int mlx5_devlink_auxdev_params_register(struct devlink *devlink)
 
 static void mlx5_devlink_auxdev_params_unregister(struct devlink *devlink)
 {
+	mlx5_devlink_vnet_param_unregister(devlink);
 	mlx5_devlink_rdma_param_unregister(devlink);
 	mlx5_devlink_eth_param_unregister(devlink);
 }

drivers/net/ethernet/mellanox/mlx5/core/mlx5_core.h

@@ -275,5 +275,6 @@ static inline u32 mlx5_sriov_get_vf_total_msix(struct pci_dev *pdev)
 
 bool mlx5_eth_supported(struct mlx5_core_dev *dev);
 bool mlx5_rdma_supported(struct mlx5_core_dev *dev);
+bool mlx5_vnet_supported(struct mlx5_core_dev *dev);
 
 #endif /* __MLX5_CORE_H__ */