* [PATCH net-next V2 1/2] devlink: add generic device max_sfs parameter
2026-05-19 20:04 [PATCH net-next V2 0/2] devlink: add generic max_sfs parameter and mlx5 support Tariq Toukan
@ 2026-05-19 20:04 ` Tariq Toukan
2026-05-19 20:04 ` [PATCH net-next V2 2/2] net/mlx5: implement " Tariq Toukan
1 sibling, 0 replies; 3+ messages in thread
From: Tariq Toukan @ 2026-05-19 20:04 UTC (permalink / raw)
To: Eric Dumazet, Jakub Kicinski, Paolo Abeni, Andrew Lunn,
David S. Miller
Cc: Jiri Pirko, Simon Horman, Jonathan Corbet, Shuah Khan,
Saeed Mahameed, Leon Romanovsky, Tariq Toukan, Mark Bloch,
Vlad Dumitrescu, Aleksandr Loktionov, Daniel Zahka, David Ahern,
Nikolay Aleksandrov, netdev, linux-doc, linux-kernel, linux-rdma,
Gal Pressman, Dragos Tatulea, Jiri Pirko, Nikolay Aleksandrov
From: Nikolay Aleksandrov <nikolay@nvidia.com>
Add a new generic devlink device parameter (max_sfs) to control if and
how many light-weight NIC subfunctions can be created. Subfunctions are
a light-weight network functions backed by an underlying PCI function.
Their lifecycle can already be managed by devlink, but currently users
cannot enable them in the device. They can be enabled/disabled only via
external vendor tools. This parameter allows subfunctions to be enabled
(>0) or disabled (0) via devlink. A subsequent patch will add support
for max_sfs to the mlx5 driver.
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
Documentation/networking/devlink/devlink-params.rst | 6 ++++++
include/net/devlink.h | 4 ++++
net/devlink/param.c | 5 +++++
3 files changed, 15 insertions(+)
diff --git a/Documentation/networking/devlink/devlink-params.rst b/Documentation/networking/devlink/devlink-params.rst
index ea17756dcda6..29b8a9246fb6 100644
--- a/Documentation/networking/devlink/devlink-params.rst
+++ b/Documentation/networking/devlink/devlink-params.rst
@@ -165,3 +165,9 @@ own name.
- u32
- Controls the maximum number of MAC address filters that can be assigned
to a Virtual Function (VF).
+ * - ``max_sfs``
+ - u32
+ - The maximum number of subfunctions which can be created on the device.
+ Modifying this parameter may require a device restart and PCI bus
+ rescanning because the BAR layout may change. A value of 0 disables
+ subfunction creation.
diff --git a/include/net/devlink.h b/include/net/devlink.h
index bcd31de1f890..4ec455cfe7a4 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -546,6 +546,7 @@ enum devlink_param_generic_id {
DEVLINK_PARAM_GENERIC_ID_TOTAL_VFS,
DEVLINK_PARAM_GENERIC_ID_NUM_DOORBELLS,
DEVLINK_PARAM_GENERIC_ID_MAX_MAC_PER_VF,
+ DEVLINK_PARAM_GENERIC_ID_MAX_SFS,
/* add new param generic ids above here*/
__DEVLINK_PARAM_GENERIC_ID_MAX,
@@ -619,6 +620,9 @@ enum devlink_param_generic_id {
#define DEVLINK_PARAM_GENERIC_MAX_MAC_PER_VF_NAME "max_mac_per_vf"
#define DEVLINK_PARAM_GENERIC_MAX_MAC_PER_VF_TYPE DEVLINK_PARAM_TYPE_U32
+#define DEVLINK_PARAM_GENERIC_MAX_SFS_NAME "max_sfs"
+#define DEVLINK_PARAM_GENERIC_MAX_SFS_TYPE DEVLINK_PARAM_TYPE_U32
+
#define DEVLINK_PARAM_GENERIC(_id, _cmodes, _get, _set, _validate) \
{ \
.id = DEVLINK_PARAM_GENERIC_ID_##_id, \
diff --git a/net/devlink/param.c b/net/devlink/param.c
index cf95268da5b0..523243e49d88 100644
--- a/net/devlink/param.c
+++ b/net/devlink/param.c
@@ -117,6 +117,11 @@ static const struct devlink_param devlink_param_generic[] = {
.name = DEVLINK_PARAM_GENERIC_MAX_MAC_PER_VF_NAME,
.type = DEVLINK_PARAM_GENERIC_MAX_MAC_PER_VF_TYPE,
},
+ {
+ .id = DEVLINK_PARAM_GENERIC_ID_MAX_SFS,
+ .name = DEVLINK_PARAM_GENERIC_MAX_SFS_NAME,
+ .type = DEVLINK_PARAM_GENERIC_MAX_SFS_TYPE,
+ },
};
static int devlink_param_generic_verify(const struct devlink_param *param)
--
2.44.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH net-next V2 2/2] net/mlx5: implement max_sfs parameter
2026-05-19 20:04 [PATCH net-next V2 0/2] devlink: add generic max_sfs parameter and mlx5 support Tariq Toukan
2026-05-19 20:04 ` [PATCH net-next V2 1/2] devlink: add generic device max_sfs parameter Tariq Toukan
@ 2026-05-19 20:04 ` Tariq Toukan
1 sibling, 0 replies; 3+ messages in thread
From: Tariq Toukan @ 2026-05-19 20:04 UTC (permalink / raw)
To: Eric Dumazet, Jakub Kicinski, Paolo Abeni, Andrew Lunn,
David S. Miller
Cc: Jiri Pirko, Simon Horman, Jonathan Corbet, Shuah Khan,
Saeed Mahameed, Leon Romanovsky, Tariq Toukan, Mark Bloch,
Vlad Dumitrescu, Aleksandr Loktionov, Daniel Zahka, David Ahern,
Nikolay Aleksandrov, netdev, linux-doc, linux-kernel, linux-rdma,
Gal Pressman, Dragos Tatulea, Jiri Pirko, Nikolay Aleksandrov
From: Nikolay Aleksandrov <nikolay@nvidia.com>
Implement max_sfs generic parameter to allow users to control the total
light-weight NIC subfunctions that can be created using devlink instead
of external vendor tools. A value of 0 will effectively disable creation
of new subfunction devices. A warning is sent to user-space via extack
(returning extack without error code is interpreted as a warning by
user-space tools).
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
Documentation/networking/devlink/mlx5.rst | 7 +-
.../mellanox/mlx5/core/lib/nv_param.c | 83 ++++++++++++++++++-
2 files changed, 86 insertions(+), 4 deletions(-)
diff --git a/Documentation/networking/devlink/mlx5.rst b/Documentation/networking/devlink/mlx5.rst
index 4bba4d780a4a..f5e2dccafa5a 100644
--- a/Documentation/networking/devlink/mlx5.rst
+++ b/Documentation/networking/devlink/mlx5.rst
@@ -45,8 +45,13 @@ Parameters
- The range is between 1 and a device-specific max.
- Applies to each physical function (PF) independently, if the device
supports it. Otherwise, it applies symmetrically to all PFs.
+ * - ``max_sfs``
+ - permanent
+ - The range is between 0 and a device-specific max.
+ - Applies to each physical function (PF) independently.
-Note: permanent parameters such as ``enable_sriov`` and ``total_vfs`` require FW reset to take effect
+Note: permanent parameters such as ``enable_sriov``, ``total_vfs`` and ``max_sfs``
+ require FW reset to take effect
.. code-block:: bash
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
index 19bb620b7436..eff3a67e4ca0 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
@@ -68,7 +68,9 @@ struct mlx5_ifc_mnvda_reg_bits {
struct mlx5_ifc_nv_global_pci_conf_bits {
u8 sriov_valid[0x1];
- u8 reserved_at_1[0x10];
+ u8 reserved_at_1[0xa];
+ u8 per_pf_num_sf[0x1];
+ u8 reserved_at_c[0x5];
u8 per_pf_total_vf[0x1];
u8 reserved_at_12[0xe];
@@ -93,9 +95,11 @@ struct mlx5_ifc_nv_global_pci_cap_bits {
};
struct mlx5_ifc_nv_pf_pci_conf_bits {
- u8 reserved_at_0[0x9];
+ u8 log_sf_bar_size[0x8];
+ u8 pf_total_sf_en[0x1];
u8 pf_total_vf_en[0x1];
- u8 reserved_at_a[0x16];
+ u8 reserved_at_a[0x6];
+ u8 total_sf[0x10];
u8 reserved_at_20[0x20];
@@ -755,6 +759,76 @@ static int mlx5_devlink_total_vfs_validate(struct devlink *devlink, u32 id,
return 0;
}
+static int mlx5_devlink_max_sfs_get(struct devlink *devlink, u32 id,
+ struct devlink_param_gset_ctx *ctx,
+ struct netlink_ext_ack *extack)
+{
+ struct mlx5_core_dev *dev = devlink_priv(devlink);
+ u32 mnvda[MLX5_ST_SZ_DW(mnvda_reg)] = {};
+ void *data;
+ int err;
+
+ err = mlx5_nv_param_read_per_host_pf_conf(dev, mnvda, sizeof(mnvda));
+ if (err) {
+ NL_SET_ERR_MSG_MOD(extack, "Failed to read PF configuration");
+ return err;
+ }
+
+ data = MLX5_ADDR_OF(mnvda_reg, mnvda, configuration_item_data);
+ ctx->val.vu32 = MLX5_GET(nv_pf_pci_conf, data, total_sf);
+
+ return 0;
+}
+
+static int mlx5_devlink_max_sfs_set(struct devlink *devlink, u32 id,
+ struct devlink_param_gset_ctx *ctx,
+ struct netlink_ext_ack *extack)
+{
+ struct mlx5_core_dev *dev = devlink_priv(devlink);
+ u32 mnvda[MLX5_ST_SZ_DW(mnvda_reg)] = {};
+ void *data;
+ int err;
+
+ err = mlx5_nv_param_read_global_pci_conf(dev, mnvda, sizeof(mnvda));
+ if (err) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "Failed to read global PCI configuration");
+ return err;
+ }
+
+ data = MLX5_ADDR_OF(mnvda_reg, mnvda, configuration_item_data);
+ MLX5_SET(nv_global_pci_conf, data, per_pf_num_sf, !!ctx->val.vu32);
+
+ err = mlx5_nv_param_write(dev, mnvda, sizeof(mnvda));
+ if (err) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "Failed to change per_pf_num_sf global PCI configuration");
+ return err;
+ }
+
+ memset(mnvda, 0, sizeof(mnvda));
+ err = mlx5_nv_param_read_per_host_pf_conf(dev, mnvda, sizeof(mnvda));
+ if (err) {
+ NL_SET_ERR_MSG_MOD(extack, "Failed to read PF configuration");
+ return err;
+ }
+
+ data = MLX5_ADDR_OF(mnvda_reg, mnvda, configuration_item_data);
+ MLX5_SET(nv_pf_pci_conf, data, log_sf_bar_size, ctx->val.vu32 ? 12 : 0);
+ MLX5_SET(nv_pf_pci_conf, data, pf_total_sf_en, !!ctx->val.vu32);
+ MLX5_SET(nv_pf_pci_conf, data, total_sf, ctx->val.vu32);
+
+ err = mlx5_nv_param_write(dev, mnvda, sizeof(mnvda));
+ if (err) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "Failed to change PF PCI configuration");
+ return err;
+ }
+ NL_SET_ERR_MSG(extack, "Modifying max_sfs requires a reboot");
+
+ return 0;
+}
+
static const struct devlink_param mlx5_nv_param_devlink_params[] = {
DEVLINK_PARAM_GENERIC(ENABLE_SRIOV, BIT(DEVLINK_PARAM_CMODE_PERMANENT),
mlx5_devlink_enable_sriov_get,
@@ -763,6 +837,9 @@ static const struct devlink_param mlx5_nv_param_devlink_params[] = {
mlx5_devlink_total_vfs_get,
mlx5_devlink_total_vfs_set,
mlx5_devlink_total_vfs_validate),
+ DEVLINK_PARAM_GENERIC(MAX_SFS, BIT(DEVLINK_PARAM_CMODE_PERMANENT),
+ mlx5_devlink_max_sfs_get,
+ mlx5_devlink_max_sfs_set, NULL),
DEVLINK_PARAM_DRIVER(MLX5_DEVLINK_PARAM_ID_CQE_COMPRESSION_TYPE,
"cqe_compress_type", DEVLINK_PARAM_TYPE_STRING,
BIT(DEVLINK_PARAM_CMODE_PERMANENT),
--
2.44.0
^ permalink raw reply related [flat|nested] 3+ messages in thread