[PATCH net-next 03/14] net/mlx5: Implement cqe_compress_type via devlink params

Saeed Mahameed
2025-02-28T02:13:27Z

From: Saeed Mahameed <saeedm@nvidia.com>

Selects which algorithm should be used by the NIC in order to decide rate of
CQE compression dependeng on PCIe bus conditions.

Supported values:

1) balanced, merges fewer CQEs, resulting in a moderate compression ratio
but maintaining a balance between bandwidth savings and performance
2) aggressive, merges more CQEs into a single entry, achieving a higher
compression rate and maximizing performance, particularly under high
traffic loads.

Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
---
Documentation/networking/devlink/mlx5.rst | 9 +
.../net/ethernet/mellanox/mlx5/core/Makefile | 2 +-
.../net/ethernet/mellanox/mlx5/core/devlink.c | 8 +
.../net/ethernet/mellanox/mlx5/core/devlink.h | 1 +
.../mellanox/mlx5/core/lib/nv_param.c | 234 ++++++++++++++++++
.../mellanox/mlx5/core/lib/nv_param.h | 14 ++
include/linux/mlx5/driver.h | 1 +
7 files changed, 268 insertions(+), 1 deletion(-)
create mode 100644 drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
create mode 100644 drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.h

diff --git a/Documentation/networking/devlink/mlx5.rst b/Documentation/networking/devlink/mlx5.rst
index 7febe0aecd53..417e5cdcd35d 100644
--- a/Documentation/networking/devlink/mlx5.rst
+++ b/Documentation/networking/devlink/mlx5.rst
@@ -117,6 +117,15 @@ parameters.
- driverinit
- Control the size (in packets) of the hairpin queues.

+ * - ``cqe_compress_type``
+ - string
+ - permanent
+ - Configure which algorithm should be used by the NIC in order to decide
+ rate of CQE compression dependeng on PCIe bus conditions.
+
+ * ``balanced`` : Merges fewer CQEs, resulting in a moderate compression ratio but maintaining a balance between bandwidth savings and performance
+ * ``aggressive`` : Merges more CQEs into a single entry, achieving a higher compression rate and maximizing performance, particularly under high traffic loads
+
The ``mlx5`` driver supports reloading via ``DEVLINK_CMD_RELOAD``

Info versions
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/Makefile b/drivers/net/ethernet/mellanox/mlx5/core/Makefile
index 568bbe5f83f5..31a6406a4814 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/Makefile
+++ b/drivers/net/ethernet/mellanox/mlx5/core/Makefile
@@ -17,7 +17,7 @@ mlx5_core-y := main.o cmd.o debugfs.o fw.o eq.o uar.o pagealloc.o \
fs_counters.o fs_ft_pool.o rl.o lag/debugfs.o lag/lag.o dev.o events.o wq.o lib/gid.o \
lib/devcom.o lib/pci_vsc.o lib/dm.o lib/fs_ttc.o diag/fs_tracepoint.o \
diag/fw_tracer.o diag/crdump.o devlink.o diag/rsc_dump.o diag/reporter_vnic.o \
- fw_reset.o qos.o lib/tout.o lib/aso.o wc.o fs_pool.o
+ fw_reset.o qos.o lib/tout.o lib/aso.o wc.o fs_pool.o lib/nv_param.o

#
# Netdev basic
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/devlink.c b/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
index 98d4306929f3..1f764ae4f4aa 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/devlink.c
@@ -10,6 +10,7 @@
#include "esw/qos.h"
#include "sf/dev/dev.h"
#include "sf/sf.h"
+#include "lib/nv_param.h"

static int mlx5_devlink_flash_update(struct devlink *devlink,
struct devlink_flash_update_params *params,
@@ -836,8 +837,14 @@ int mlx5_devlink_params_register(struct devlink *devlink)
if (err)
goto max_uc_list_err;

+ err = mlx5_nv_param_register_dl_params(devlink);
+ if (err)
+ goto nv_param_err;
+
return 0;

+nv_param_err:
+ mlx5_devlink_max_uc_list_params_unregister(devlink);
max_uc_list_err:
mlx5_devlink_auxdev_params_unregister(devlink);
auxdev_reg_err:
@@ -848,6 +855,7 @@ int mlx5_devlink_params_register(struct devlink *devlink)

void mlx5_devlink_params_unregister(struct devlink *devlink)
{
+ mlx5_nv_param_unregister_dl_params(devlink);
mlx5_devlink_max_uc_list_params_unregister(devlink);
mlx5_devlink_auxdev_params_unregister(devlink);
devl_params_unregister(devlink, mlx5_devlink_params,
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/devlink.h b/drivers/net/ethernet/mellanox/mlx5/core/devlink.h
index 961f75da6227..74bcdfa70361 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/devlink.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/devlink.h
@@ -22,6 +22,7 @@ enum mlx5_devlink_param_id {
MLX5_DEVLINK_PARAM_ID_ESW_MULTIPORT,
MLX5_DEVLINK_PARAM_ID_HAIRPIN_NUM_QUEUES,
MLX5_DEVLINK_PARAM_ID_HAIRPIN_QUEUE_SIZE,
+ MLX5_DEVLINK_PARAM_ID_CQE_COMPRESSION_TYPE
};

struct mlx5_trap_ctx {
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
new file mode 100644
index 000000000000..5ab37a88c260
--- /dev/null
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.c
@@ -0,0 +1,234 @@
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/* Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES. All rights reserved. */
+
+#include "nv_param.h"
+#include "mlx5_core.h"
+
+enum {
+ MLX5_CLASS_0_CTRL_ID_NV_SW_OFFLOAD_CONFIG = 0x10a,
+};
+
+struct mlx5_ifc_configuration_item_type_class_global_bits {
+ u8 type_class[0x8];
+ u8 parameter_index[0x18];
+};
+
+union mlx5_ifc_config_item_type_auto_bits {
+ struct mlx5_ifc_configuration_item_type_class_global_bits
+ configuration_item_type_class_global;
+ u8 reserved_at_0[0x20];
+};
+
+struct mlx5_ifc_config_item_bits {
+ u8 valid[0x2];
+ u8 priority[0x2];
+ u8 header_type[0x2];
+ u8 ovr_en[0x1];
+ u8 rd_en[0x1];
+ u8 access_mode[0x2];
+ u8 reserved_at_a[0x1];
+ u8 writer_id[0x5];
+ u8 version[0x4];
+ u8 reserved_at_14[0x2];
+ u8 host_id_valid[0x1];
+ u8 length[0x9];
+
+ union mlx5_ifc_config_item_type_auto_bits type;
+
+ u8 reserved_at_40[0x10];
+ u8 crc16[0x10];
+};
+
+struct mlx5_ifc_mnvda_reg_bits {
+ struct mlx5_ifc_config_item_bits configuration_item_header;
+
+ u8 configuration_item_data[64][0x20];
+};
+
+struct mlx5_ifc_nv_sw_offload_conf_bits {
+ u8 ip_over_vxlan_port[0x10];
+ u8 tunnel_ecn_copy_offload_disable[0x1];
+ u8 pci_atomic_mode[0x3];
+ u8 sr_enable[0x1];
+ u8 ptp_cyc2realtime[0x1];
+ u8 vector_calc_disable[0x1];
+ u8 uctx_en[0x1];
+ u8 prio_tag_required_en[0x1];
+ u8 esw_fdb_ipv4_ttl_modify_enable[0x1];
+ u8 mkey_by_name[0x1];
+ u8 ip_over_vxlan_en[0x1];
+ u8 one_qp_per_recovery[0x1];
+ u8 cqe_compression[0x3];
+ u8 tunnel_udp_entropy_proto_disable[0x1];
+ u8 reserved_at_21[0x1];
+ u8 ar_enable[0x1];
+ u8 log_max_outstanding_wqe[0x5];
+ u8 vf_migration[0x2];
+ u8 log_tx_psn_win[0x6];
+ u8 lro_log_timeout3[0x4];
+ u8 lro_log_timeout2[0x4];
+ u8 lro_log_timeout1[0x4];
+ u8 lro_log_timeout0[0x4];
+};
+
+#define MNVDA_HDR_SZ \
+ (MLX5_ST_SZ_BYTES(mnvda_reg) - MLX5_BYTE_OFF(mnvda_reg, configuration_item_data))
+
+#define MLX5_SET_CONFIG_ITEM_TYPE(_cls_name, _mnvda_ptr, _field, _val) \
+ MLX5_SET(mnvda_reg, _mnvda_ptr, \
+ configuration_item_header.type.configuration_item_type_class_##_cls_name._field, \
+ _val)
+
+#define MLX5_SET_CONFIG_HDR_LEN(_mnvda_ptr, _cls_name) \
+ MLX5_SET(mnvda_reg, _mnvda_ptr, configuration_item_header.length, \
+ MLX5_ST_SZ_BYTES(_cls_name))
+
+#define MLX5_GET_CONFIG_HDR_LEN(_mnvda_ptr) \
+ MLX5_GET(mnvda_reg, _mnvda_ptr, configuration_item_header.length)
+
+static int mlx5_nv_param_read(struct mlx5_core_dev *dev, void *mnvda, size_t len)
+{
+ u32 param_idx, type_class;
+ u32 header_len;
+ void *cls_ptr;
+ int err;
+
+ if (WARN_ON(len > MLX5_ST_SZ_BYTES(mnvda_reg)) || len < MNVDA_HDR_SZ)
+ return -EINVAL; /* A caller bug */
+
+ err = mlx5_core_access_reg(dev, mnvda, len, mnvda, len, MLX5_REG_MNVDA, 0, 0);
+ if (!err)
+ return 0;
+
+ cls_ptr = MLX5_ADDR_OF(mnvda_reg, mnvda,
+ configuration_item_header.type.configuration_item_type_class_global);
+
+ type_class = MLX5_GET(configuration_item_type_class_global, cls_ptr, type_class);
+ param_idx = MLX5_GET(configuration_item_type_class_global, cls_ptr, parameter_index);
+ header_len = MLX5_GET_CONFIG_HDR_LEN(mnvda);
+
+ mlx5_core_warn(dev, "Failed to read mnvda reg: type_class 0x%x, param_idx 0x%x, header_len %u, err %d\n",
+ type_class, param_idx, header_len, err);
+
+ /* Let devlink skip this one if it fails, kernel log will have the failure */
+ return -EOPNOTSUPP;
+}
+
+static int mlx5_nv_param_write(struct mlx5_core_dev *dev, void *mnvda, size_t len)
+{
+ if (WARN_ON(len > MLX5_ST_SZ_BYTES(mnvda_reg)) || len < MNVDA_HDR_SZ)
+ return -EINVAL;
+
+ if (WARN_ON(MLX5_GET_CONFIG_HDR_LEN(mnvda) == 0))
+ return -EINVAL;
+
+ return mlx5_core_access_reg(dev, mnvda, len, mnvda, len, MLX5_REG_MNVDA, 0, 1);
+}
+
+static int
+mlx5_nv_param_read_sw_offload_conf(struct mlx5_core_dev *dev, void *mnvda, size_t len)
+{
+ MLX5_SET_CONFIG_ITEM_TYPE(global, mnvda, type_class, 0);
+ MLX5_SET_CONFIG_ITEM_TYPE(global, mnvda, parameter_index,
+ MLX5_CLASS_0_CTRL_ID_NV_SW_OFFLOAD_CONFIG);
+ MLX5_SET_CONFIG_HDR_LEN(mnvda, nv_sw_offload_conf);
+
+ return mlx5_nv_param_read(dev, mnvda, len);
+}
+
+static const char *const
+ cqe_compress_str[] = { "balanced", "aggressive" };
+
+static int mlx5_nv_param_devlink_cqe_compress_get(struct devlink *devlink, u32 id,
+ struct devlink_param_gset_ctx *ctx)
+{
+ struct mlx5_core_dev *dev = devlink_priv(devlink);
+ u32 mnvda[MLX5_ST_SZ_DW(mnvda_reg)] = {};
+ u8 value = U8_MAX;
+ void *data;
+ int err;
+
+ err = mlx5_nv_param_read_sw_offload_conf(dev, mnvda, sizeof(mnvda));
+ if (err)
+ return err;
+
+ data = MLX5_ADDR_OF(mnvda_reg, mnvda, configuration_item_data);
+ value = MLX5_GET(nv_sw_offload_conf, data, cqe_compression);
+
+ if (value >= ARRAY_SIZE(cqe_compress_str))
+ return -EOPNOTSUPP;
+
+ strscpy(ctx->val.vstr, cqe_compress_str[value], sizeof(ctx->val.vstr));
+ return 0;
+}
+
+static int
+mlx5_nv_param_devlink_cqe_compress_validate(struct devlink *devlink, u32 id,
+ union devlink_param_value val,
+ struct netlink_ext_ack *extack)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(cqe_compress_str); i++) {
+ if (!strcmp(val.vstr, cqe_compress_str[i]))
+ return 0;
+ }
+
+ NL_SET_ERR_MSG_MOD(extack,
+ "Invalid value, supported values are balanced/aggressive");
+ return -EOPNOTSUPP;
+}
+
+static int mlx5_nv_param_devlink_cqe_compress_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)] = {};
+ int err = 0;
+ void *data;
+ u8 value;
+
+ if (!strcmp(ctx->val.vstr, "aggressive"))
+ value = 1;
+ else /* balanced: can't be anything else already validated above */
+ value = 0;
+
+ err = mlx5_nv_param_read_sw_offload_conf(dev, mnvda, sizeof(mnvda));
+ if (err) {
+ NL_SET_ERR_MSG_MOD(extack, "Failed to read sw_offload_conf mnvda reg");
+ return err;
+ }
+
+ data = MLX5_ADDR_OF(mnvda_reg, mnvda, configuration_item_data);
+ MLX5_SET(nv_sw_offload_conf, data, cqe_compression, value);
+
+ return mlx5_nv_param_write(dev, mnvda, sizeof(mnvda));
+}
+
+static const struct devlink_param mlx5_nv_param_devlink_params[] = {
+ DEVLINK_PARAM_DRIVER(MLX5_DEVLINK_PARAM_ID_CQE_COMPRESSION_TYPE,
+ "cqe_compress_type", DEVLINK_PARAM_TYPE_STRING,
+ BIT(DEVLINK_PARAM_CMODE_PERMANENT),
+ mlx5_nv_param_devlink_cqe_compress_get,
+ mlx5_nv_param_devlink_cqe_compress_set,
+ mlx5_nv_param_devlink_cqe_compress_validate),
+};
+
+int mlx5_nv_param_register_dl_params(struct devlink *devlink)
+{
+ if (!mlx5_core_is_pf(devlink_priv(devlink)))
+ return 0;
+
+ return devl_params_register(devlink, mlx5_nv_param_devlink_params,
+ ARRAY_SIZE(mlx5_nv_param_devlink_params));
+}
+
+void mlx5_nv_param_unregister_dl_params(struct devlink *devlink)
+{
+ if (!mlx5_core_is_pf(devlink_priv(devlink)))
+ return;
+
+ devl_params_unregister(devlink, mlx5_nv_param_devlink_params,
+ ARRAY_SIZE(mlx5_nv_param_devlink_params));
+}
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.h b/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.h
new file mode 100644
index 000000000000..9f4922ff7745
--- /dev/null
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/nv_param.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
+/* Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES. All rights reserved. */
+
+#ifndef __MLX5_NV_PARAM_H
+#define __MLX5_NV_PARAM_H
+
+#include <linux/mlx5/driver.h>
+#include "devlink.h"
+
+int mlx5_nv_param_register_dl_params(struct devlink *devlink);
+void mlx5_nv_param_unregister_dl_params(struct devlink *devlink);
+
+#endif
+
diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h
index 46bd7550adf8..2ce3c04fe237 100644
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -135,6 +135,7 @@ enum {
MLX5_REG_MTCAP = 0x9009,
MLX5_REG_MTMP = 0x900A,
MLX5_REG_MCIA = 0x9014,
+ MLX5_REG_MNVDA = 0x9024,
MLX5_REG_MFRL = 0x9028,
MLX5_REG_MLCR = 0x902b,
MLX5_REG_MRTC = 0x902d,
--
2.48.1