Mellanox ConnectX(R) mlx5 core VPI Network Driver

Copyright (c) 2019, Mellanox Technologies LTD.

Enabling the driver and kconfig options

mlx5 core is modular and most of the major mlx5 core driver features can be selected (compiled in/out)
at build time via kernel Kconfig flags.
Basic features, ethernet net device rx/tx offloads and XDP, are available with the most basic flags
CONFIG_MLX5_CORE=y/m and CONFIG_MLX5_CORE_EN=y.
For the list of advanced features please see below.

CONFIG_MLX5_CORE=(y/m/n) (module mlx5_core.ko)

The driver can be enabled by choosing CONFIG_MLX5_CORE=y/m in kernel config.
This will provide mlx5 core driver for mlx5 ulps to interface with (mlx5e, mlx5_ib).

CONFIG_MLX5_CORE_EN=(y/n)

Choosing this option will allow basic ethernet netdevice support with all of the standard rx/tx offloads.
mlx5e is the mlx5 ulp driver which provides netdevice kernel interface, when chosen, mlx5e will be
built-in into mlx5_core.ko.

CONFIG_MLX5_EN_ARFS=(y/n)

Enables Hardware-accelerated receive flow steering (arfs) support, and ntuple filtering.

CONFIG_MLX5_EN_RXNFC=(y/n)

Enables ethtool receive network flow classification, which allows user defined
flow rules to direct traffic into arbitrary rx queue via ethtool set/get_rxnfc API.

CONFIG_MLX5_CORE_EN_DCB=(y/n):

CONFIG_MLX5_MPFS=(y/n)

Ethernet Multi-Physical Function Switch (MPFS) support in ConnectX NIC.
MPFs is required for when Multi-Host configuration is enabled to allow passing
user configured unicast MAC addresses to the requesting PF.

CONFIG_MLX5_ESWITCH=(y/n)

Ethernet SRIOV E-Switch support in ConnectX NIC. E-Switch provides internal SRIOV packet steering
and switching for the enabled VFs and PF in two available modes:

CONFIG_MLX5_CORE_IPOIB=(y/n)

IPoIB offloads & acceleration support.
Requires CONFIG_MLX5_CORE_EN to provide an accelerated interface for the rdma
IPoIB ulp netdevice.

CONFIG_MLX5_FPGA=(y/n)

Build support for the Innova family of network cards by Mellanox Technologies.
Innova network cards are comprised of a ConnectX chip and an FPGA chip on one board.
If you select this option, the mlx5_core driver will include the Innova FPGA core and allow
building sandbox-specific client drivers.

CONFIG_MLX5_EN_IPSEC=(y/n)

CONFIG_MLX5_EN_TLS=(y/n)

TLS cryptography-offload accelaration.

CONFIG_MLX5_INFINIBAND=(y/n/m) (module mlx5_ib.ko)

Provides low-level InfiniBand/RDMA and RoCE support.

CONFIG_MLX5_SF=(y/n)

Build support for subfunction.
Subfunctons are more light weight than PCI SRIOV VFs. Choosing this option
will enable support for creating subfunction devices.

External options ( Choose if the corresponding mlx5 feature is required )

  • CONFIG_PTP_1588_CLOCK: When chosen, mlx5 ptp support will be enabled
  • CONFIG_VXLAN: When chosen, mlx5 vxlan support will be enabled.
  • CONFIG_MLXFW: When chosen, mlx5 firmware flashing support will be enabled (via devlink and ethtool).

Bridge offload

The mlx5 driver implements support for offloading bridge rules when in switchdev mode. Linux bridge FDBs are automatically offloaded when mlx5 switchdev representor is attached to bridge.

  • Change device to switchdev mode:

    $ devlink dev eswitch set pci/0000:06:00.0 mode switchdev
    
  • Attach mlx5 switchdev representor ‘enp8s0f0’ to bridge netdev ‘bridge1’:

    $ ip link set enp8s0f0 master bridge1
    

VLANs

Following bridge VLAN functions are supported by mlx5:

  • VLAN filtering (including multiple VLANs per port):

    $ ip link set bridge1 type bridge vlan_filtering 1
    $ bridge vlan add dev enp8s0f0 vid 2-3
    
  • VLAN push on bridge ingress:

    $ bridge vlan add dev enp8s0f0 vid 3 pvid
    
  • VLAN pop on bridge egress:

    $ bridge vlan add dev enp8s0f0 vid 3 untagged
    

mlx5 subfunction

mlx5 supports subfunction management using devlink port (see Devlink Port) interface.

A Subfunction has its own function capabilities and its own resources. This means a subfunction has its own dedicated queues (txq, rxq, cq, eq). These queues are neither shared nor stolen from the parent PCI function.

When a subfunction is RDMA capable, it has its own QP1, GID table and rdma resources neither shared nor stolen from the parent PCI function.

A subfunction has a dedicated window in PCI BAR space that is not shared with ther other subfunctions or the parent PCI function. This ensures that all devices (netdev, rdma, vdpa etc.) of the subfunction accesses only assigned PCI BAR space.

A Subfunction supports eswitch representation through which it supports tc offloads. The user configures eswitch to send/receive packets from/to the subfunction port.

Subfunctions share PCI level resources such as PCI MSI-X IRQs with other subfunctions and/or with its parent PCI function.

Example mlx5 software, system and device view:

      _______
     | admin |
     | user  |----------
     |_______|         |
         |             |
     ____|____       __|______            _________________
    |         |     |         |          |                 |
    | devlink |     | tc tool |          |    user         |
    | tool    |     |_________|          | applications    |
    |_________|         |                |_________________|
          |             |                   |          |
          |             |                   |          |         Userspace
+---------|-------------|-------------------|----------|--------------------+
          |             |           +----------+   +----------+   Kernel
          |             |           |  netdev  |   | rdma dev |
          |             |           +----------+   +----------+
  (devlink port add/del |              ^               ^
   port function set)   |              |               |
          |             |              +---------------|
     _____|___          |              |        _______|_______
    |         |         |              |       | mlx5 class    |
    | devlink |   +------------+       |       |   drivers     |
    | kernel  |   | rep netdev |       |       |(mlx5_core,ib) |
    |_________|   +------------+       |       |_______________|
          |             |              |               ^
  (devlink ops)         |              |          (probe/remove)
 _________|________     |              |           ____|________
| subfunction      |    |     +---------------+   | subfunction |
| management driver|-----     | subfunction   |---|  driver     |
| (mlx5_core)      |          | auxiliary dev |   | (mlx5_core) |
|__________________|          +---------------+   |_____________|
          |                                            ^
 (sf add/del, vhca events)                             |
          |                                      (device add/del)
     _____|____                                    ____|________
    |          |                                  | subfunction |
    |  PCI NIC |---- activate/deactive events---->| host driver |
    |__________|                                  | (mlx5_core) |
                                                  |_____________|

Subfunction is created using devlink port interface.

  • Change device to switchdev mode:

    $ devlink dev eswitch set pci/0000:06:00.0 mode switchdev
    
  • Add a devlink port of subfunction flaovur:

    $ devlink port add pci/0000:06:00.0 flavour pcisf pfnum 0 sfnum 88
    pci/0000:06:00.0/32768: type eth netdev eth6 flavour pcisf controller 0 pfnum 0 sfnum 88 external false splittable false
      function:
        hw_addr 00:00:00:00:00:00 state inactive opstate detached
    
  • Show a devlink port of the subfunction:

    $ devlink port show pci/0000:06:00.0/32768
    pci/0000:06:00.0/32768: type eth netdev enp6s0pf0sf88 flavour pcisf pfnum 0 sfnum 88
      function:
        hw_addr 00:00:00:00:00:00 state inactive opstate detached
    
  • Delete a devlink port of subfunction after use:

    $ devlink port del pci/0000:06:00.0/32768
    

mlx5 function attributes

The mlx5 driver provides a mechanism to setup PCI VF/SF function attributes in a unified way for SmartNIC and non-SmartNIC.

This is supported only when the eswitch mode is set to switchdev. Port function configuration of the PCI VF/SF is supported through devlink eswitch port.

Port function attributes should be set before PCI VF/SF is enumerated by the driver.

MAC address setup

mlx5 driver provides mechanism to setup the MAC address of the PCI VF/SF.

The configured MAC address of the PCI VF/SF will be used by netdevice and rdma device created for the PCI VF/SF.

  • Get the MAC address of the VF identified by its unique devlink port index:

    $ devlink port show pci/0000:06:00.0/2
    pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1
      function:
        hw_addr 00:00:00:00:00:00
    
  • Set the MAC address of the VF identified by its unique devlink port index:

    $ devlink port function set pci/0000:06:00.0/2 hw_addr 00:11:22:33:44:55
    
    $ devlink port show pci/0000:06:00.0/2
    pci/0000:06:00.0/2: type eth netdev enp6s0pf0vf1 flavour pcivf pfnum 0 vfnum 1
      function:
        hw_addr 00:11:22:33:44:55
    
  • Get the MAC address of the SF identified by its unique devlink port index:

    $ devlink port show pci/0000:06:00.0/32768
    pci/0000:06:00.0/32768: type eth netdev enp6s0pf0sf88 flavour pcisf pfnum 0 sfnum 88
      function:
        hw_addr 00:00:00:00:00:00
    
  • Set the MAC address of the VF identified by its unique devlink port index:

    $ devlink port function set pci/0000:06:00.0/32768 hw_addr 00:00:00:00:88:88
    
    $ devlink port show pci/0000:06:00.0/32768
    pci/0000:06:00.0/32768: type eth netdev enp6s0pf0sf88 flavour pcivf pfnum 0 sfnum 88
      function:
        hw_addr 00:00:00:00:88:88
    

SF state setup

To use the SF, the user must active the SF using the SF function state attribute.

  • Get the state of the SF identified by its unique devlink port index:

    $ devlink port show ens2f0npf0sf88
    pci/0000:06:00.0/32768: type eth netdev ens2f0npf0sf88 flavour pcisf controller 0 pfnum 0 sfnum 88 external false splittable false
      function:
        hw_addr 00:00:00:00:88:88 state inactive opstate detached
    
  • Activate the function and verify its state is active:

    $ devlink port function set ens2f0npf0sf88 state active
    
    $ devlink port show ens2f0npf0sf88
    pci/0000:06:00.0/32768: type eth netdev ens2f0npf0sf88 flavour pcisf controller 0 pfnum 0 sfnum 88 external false splittable false
      function:
        hw_addr 00:00:00:00:88:88 state active opstate detached
    

Upon function activation, the PF driver instance gets the event from the device that a particular SF was activated. It’s the cue to put the device on bus, probe it and instantiate the devlink instance and class specific auxiliary devices for it.

  • Show the auxiliary device and port of the subfunction:

    $ devlink dev show
    devlink dev show auxiliary/mlx5_core.sf.4
    
    $ devlink port show auxiliary/mlx5_core.sf.4/1
    auxiliary/mlx5_core.sf.4/1: type eth netdev p0sf88 flavour virtual port 0 splittable false
    
    $ rdma link show mlx5_0/1
    link mlx5_0/1 state ACTIVE physical_state LINK_UP netdev p0sf88
    
    $ rdma dev show
    8: rocep6s0f1: node_type ca fw 16.29.0550 node_guid 248a:0703:00b3:d113 sys_image_guid 248a:0703:00b3:d112
    13: mlx5_0: node_type ca fw 16.29.0550 node_guid 0000:00ff:fe00:8888 sys_image_guid 248a:0703:00b3:d112
    
  • Subfunction auxiliary device and class device hierarchy:

                mlx5_core.sf.4
         (subfunction auxiliary device)
                      /\
                     /  \
                    /    \
                   /      \
                  /        \
     mlx5_core.eth.4     mlx5_core.rdma.4
    (sf eth aux dev)     (sf rdma aux dev)
        |                      |
        |                      |
     p0sf88                  mlx5_0
    (sf netdev)          (sf rdma device)
    

Additionally, the SF port also gets the event when the driver attaches to the auxiliary device of the subfunction. This results in changing the operational state of the function. This provides visiblity to the user to decide when is it safe to delete the SF port for graceful termination of the subfunction.

  • Show the SF port operational state:

    $ devlink port show ens2f0npf0sf88
    pci/0000:06:00.0/32768: type eth netdev ens2f0npf0sf88 flavour pcisf controller 0 pfnum 0 sfnum 88 external false splittable false
      function:
        hw_addr 00:00:00:00:88:88 state active opstate attached
    

mlx5 tracepoints

mlx5 driver provides internal trace points for tracking and debugging using kernel tracepoints interfaces (refer to ftrace - Function Tracer).

For the list of support mlx5 events check /sys/kernel/debug/tracing/events/mlx5/

tc and eswitch offloads tracepoints:

  • mlx5e_configure_flower: trace flower filter actions and cookies offloaded to mlx5:

    $ echo mlx5:mlx5e_configure_flower >> /sys/kernel/debug/tracing/set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    tc-6535  [019] ...1  2672.404466: mlx5e_configure_flower: cookie=0000000067874a55 actions= REDIRECT
    
  • mlx5e_delete_flower: trace flower filter actions and cookies deleted from mlx5:

    $ echo mlx5:mlx5e_delete_flower >> /sys/kernel/debug/tracing/set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    tc-6569  [010] .N.1  2686.379075: mlx5e_delete_flower: cookie=0000000067874a55 actions= NULL
    
  • mlx5e_stats_flower: trace flower stats request:

    $ echo mlx5:mlx5e_stats_flower >> /sys/kernel/debug/tracing/set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    tc-6546  [010] ...1  2679.704889: mlx5e_stats_flower: cookie=0000000060eb3d6a bytes=0 packets=0 lastused=4295560217
    
  • mlx5e_tc_update_neigh_used_value: trace tunnel rule neigh update value offloaded to mlx5:

    $ echo mlx5:mlx5e_tc_update_neigh_used_value >> /sys/kernel/debug/tracing/set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    kworker/u48:4-8806  [009] ...1 55117.882428: mlx5e_tc_update_neigh_used_value: netdev: ens1f0 IPv4: 1.1.1.10 IPv6: ::ffff:1.1.1.10 neigh_used=1
    
  • mlx5e_rep_neigh_update: trace neigh update tasks scheduled due to neigh state change events:

    $ echo mlx5:mlx5e_rep_neigh_update >> /sys/kernel/debug/tracing/set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    kworker/u48:7-2221  [009] ...1  1475.387435: mlx5e_rep_neigh_update: netdev: ens1f0 MAC: 24:8a:07:9a:17:9a IPv4: 1.1.1.10 IPv6: ::ffff:1.1.1.10 neigh_connected=1
    

Bridge offloads tracepoints:

  • mlx5_esw_bridge_fdb_entry_init: trace bridge FDB entry offloaded to mlx5:

    $ echo mlx5:mlx5_esw_bridge_fdb_entry_init >> set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    kworker/u20:9-2217    [003] ...1   318.582243: mlx5_esw_bridge_fdb_entry_init: net_device=enp8s0f0_0 addr=e4:fd:05:08:00:02 vid=0 flags=0 used=0
    
  • mlx5_esw_bridge_fdb_entry_cleanup: trace bridge FDB entry deleted from mlx5:

    $ echo mlx5:mlx5_esw_bridge_fdb_entry_cleanup >> set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    ip-2581    [005] ...1   318.629871: mlx5_esw_bridge_fdb_entry_cleanup: net_device=enp8s0f0_1 addr=e4:fd:05:08:00:03 vid=0 flags=0 used=16
    
  • mlx5_esw_bridge_fdb_entry_refresh: trace bridge FDB entry offload refreshed in mlx5:

    $ echo mlx5:mlx5_esw_bridge_fdb_entry_refresh >> set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    kworker/u20:8-3849    [003] ...1       466716: mlx5_esw_bridge_fdb_entry_refresh: net_device=enp8s0f0_0 addr=e4:fd:05:08:00:02 vid=3 flags=0 used=0
    
  • mlx5_esw_bridge_vlan_create: trace bridge VLAN object add on mlx5 representor:

    $ echo mlx5:mlx5_esw_bridge_vlan_create >> set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    ip-2560    [007] ...1   318.460258: mlx5_esw_bridge_vlan_create: vid=1 flags=6
    
  • mlx5_esw_bridge_vlan_cleanup: trace bridge VLAN object delete from mlx5 representor:

    $ echo mlx5:mlx5_esw_bridge_vlan_cleanup >> set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    bridge-2582    [007] ...1   318.653496: mlx5_esw_bridge_vlan_cleanup: vid=2 flags=8
    
  • mlx5_esw_bridge_vport_init: trace mlx5 vport assigned with bridge upper device:

    $ echo mlx5:mlx5_esw_bridge_vport_init >> set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    ip-2560    [007] ...1   318.458915: mlx5_esw_bridge_vport_init: vport_num=1
    
  • mlx5_esw_bridge_vport_cleanup: trace mlx5 vport removed from bridge upper device:

    $ echo mlx5:mlx5_esw_bridge_vport_cleanup >> set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    ip-5387    [000] ...1       573713: mlx5_esw_bridge_vport_cleanup: vport_num=1
    

Eswitch QoS tracepoints:

  • mlx5_esw_vport_qos_create: trace creation of transmit scheduler arbiter for vport:

    $ echo mlx5:mlx5_esw_vport_qos_create >> /sys/kernel/debug/tracing/set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    <...>-23496   [018] .... 73136.838831: mlx5_esw_vport_qos_create: (0000:82:00.0) vport=2 tsar_ix=4 bw_share=0, max_rate=0 group=000000007b576bb3
    
  • mlx5_esw_vport_qos_config: trace configuration of transmit scheduler arbiter for vport:

    $ echo mlx5:mlx5_esw_vport_qos_config >> /sys/kernel/debug/tracing/set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    <...>-26548   [023] .... 75754.223823: mlx5_esw_vport_qos_config: (0000:82:00.0) vport=1 tsar_ix=3 bw_share=34, max_rate=10000 group=000000007b576bb3
    
  • mlx5_esw_vport_qos_destroy: trace deletion of transmit scheduler arbiter for vport:

    $ echo mlx5:mlx5_esw_vport_qos_destroy >> /sys/kernel/debug/tracing/set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    <...>-27418   [004] .... 76546.680901: mlx5_esw_vport_qos_destroy: (0000:82:00.0) vport=1 tsar_ix=3
    
  • mlx5_esw_group_qos_create: trace creation of transmit scheduler arbiter for rate group:

    $ echo mlx5:mlx5_esw_group_qos_create >> /sys/kernel/debug/tracing/set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    <...>-26578   [008] .... 75776.022112: mlx5_esw_group_qos_create: (0000:82:00.0) group=000000008dac63ea tsar_ix=5
    
  • mlx5_esw_group_qos_config: trace configuration of transmit scheduler arbiter for rate group:

    $ echo mlx5:mlx5_esw_group_qos_config >> /sys/kernel/debug/tracing/set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    <...>-27303   [020] .... 76461.455356: mlx5_esw_group_qos_config: (0000:82:00.0) group=000000008dac63ea tsar_ix=5 bw_share=100 max_rate=20000
    
  • mlx5_esw_group_qos_destroy: trace deletion of transmit scheduler arbiter for group:

    $ echo mlx5:mlx5_esw_group_qos_destroy >> /sys/kernel/debug/tracing/set_event
    $ cat /sys/kernel/debug/tracing/trace
    ...
    <...>-27418   [006] .... 76547.187258: mlx5_esw_group_qos_destroy: (0000:82:00.0) group=000000007b576bb3 tsar_ix=1