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mlx5 devlink support

Documentation/networking/devlink/mlx5.rst

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.. SPDX-License-Identifier: GPL-2.0

==================== mlx5 devlink support

This document describes the devlink features implemented by the mlx5 device driver.

Parameters

.. list-table:: Generic parameters implemented

    • Name
    • Mode
    • Validation

    • enable_roce

    • driverinit

    • Type: Boolean

      If the device supports RoCE disablement, RoCE enablement state controls device support for RoCE capability. Otherwise, the control occurs in the driver stack. When RoCE is disabled at the driver level, only raw ethernet QPs are supported.

    • io_eq_size
    • driverinit
    • The range is between 64 and 4096.
    • event_eq_size
    • driverinit
    • The range is between 64 and 4096.
    • max_macs
    • driverinit
    • The range is between 1 and 2^31. Only power of 2 values are supported.

The mlx5 driver also implements the following driver-specific parameters.

.. list-table:: Driver-specific parameters implemented :widths: 5 5 5 85

    • Name
    • Type
    • Mode
    • Description

    • flow_steering_mode

    • string

    • runtime

    • Controls the flow steering mode of the driver

      • dmfs Device managed flow steering. In DMFS mode, the HW steering entities are created and managed through firmware.
      • smfs Software managed flow steering. In SMFS mode, the HW steering entities are created and manage through the driver without firmware intervention.

      SMFS mode is faster and provides better rule insertion rate compared to default DMFS mode.

    • fdb_large_groups

    • u32

    • driverinit

    • Control the number of large groups (size > 1) in the FDB table.

      • The default value is 15, and the range is between 1 and 1024.

    • esw_multiport

    • Boolean

    • runtime

    • Control MultiPort E-Switch shared fdb mode.

      An experimental mode where a single E-Switch is used and all the vports and physical ports on the NIC are connected to it.

      An example is to send traffic from a VF that is created on PF0 to an uplink that is natively associated with the uplink of PF1

      Note: Future devices, ConnectX-8 and onward, will eventually have this as the default to allow forwarding between all NIC ports in a single E-switch environment and the dual E-switch mode will likely get deprecated.

      Default: disabled

    • esw_port_metadata

    • Boolean

    • runtime

    • When applicable, disabling eswitch metadata can increase packet rate up to 20% depending on the use case and packet sizes.

      Eswitch port metadata state controls whether to internally tag packets with metadata. Metadata tagging must be enabled for multi-port RoCE, failover between representors and stacked devices. By default metadata is enabled on the supported devices in E-switch. Metadata is applicable only for E-switch in switchdev mode and users may disable it when NONE of the below use cases will be in use:

      1. HCA is in Dual/multi-port RoCE mode.
      2. VF/SF representor bonding (Usually used for Live migration)
      3. Stacked devices

      When metadata is disabled, the above use cases will fail to initialize if users try to enable them.

      Note: Setting this parameter does not take effect immediately. Setting must happen in legacy mode and eswitch port metadata takes effect after enabling switchdev mode.

    • hairpin_num_queues

    • u32

    • driverinit

    • We refer to a TC NIC rule that involves forwarding as "hairpin". Hairpin queues are mlx5 hardware specific implementation for hardware forwarding of such packets.

      Control the number of hairpin queues.

    • hairpin_queue_size
    • u32
    • driverinit
    • Control the size (in packets) of the hairpin queues.

The mlx5 driver supports reloading via DEVLINK_CMD_RELOAD

Info versions

The mlx5 driver reports the following versions

.. list-table:: devlink info versions implemented :widths: 5 5 90

    • Name
    • Type
    • Description
    • fw.psid
    • fixed
    • Used to represent the board id of the device.
    • fw.version
    • stored, running
    • Three digit major.minor.subminor firmware version number.

Health reporters

tx reporter

The tx reporter is responsible for reporting and recovering of the following three error scenarios:

  • tx timeout Report on kernel tx timeout detection. Recover by searching lost interrupts.
  • tx error completion Report on error tx completion. Recover by flushing the tx queue and reset it.
  • tx PTP port timestamping CQ unhealthy Report too many CQEs never delivered on port ts CQ. Recover by flushing and re-creating all PTP channels.

tx reporter also support on demand diagnose callback, on which it provides real time information of its send queues status.

User commands examples:

  • Diagnose send queues status::

    $ devlink health diagnose pci/0000:82:00.0 reporter tx

.. note:: This command has valid output only when interface is up, otherwise the command has empty output.

  • Show number of tx errors indicated, number of recover flows ended successfully, is autorecover enabled and graceful period from last recover::

    $ devlink health show pci/0000:82:00.0 reporter tx

rx reporter

The rx reporter is responsible for reporting and recovering of the following two error scenarios:

  • rx queues' initialization (population) timeout Population of rx queues' descriptors on ring initialization is done in napi context via triggering an irq. In case of a failure to get the minimum amount of descriptors, a timeout would occur, and descriptors could be recovered by polling the EQ (Event Queue).
  • rx completions with errors (reported by HW on interrupt context) Report on rx completion error. Recover (if needed) by flushing the related queue and reset it.

rx reporter also supports on demand diagnose callback, on which it provides real time information of its receive queues' status.

  • Diagnose rx queues' status and corresponding completion queue::

    $ devlink health diagnose pci/0000:82:00.0 reporter rx

.. note:: This command has valid output only when interface is up. Otherwise, the command has empty output.

  • Show number of rx errors indicated, number of recover flows ended successfully, is autorecover enabled, and graceful period from last recover::

    $ devlink health show pci/0000:82:00.0 reporter rx

fw reporter

The fw reporter implements diagnose and dump callbacks. It follows symptoms of fw error such as fw syndrome by triggering fw core dump and storing it into the dump buffer. The fw reporter diagnose command can be triggered any time by the user to check current fw status.

User commands examples:

  • Check fw heath status::

    $ devlink health diagnose pci/0000:82:00.0 reporter fw

  • Read FW core dump if already stored or trigger new one::

    $ devlink health dump show pci/0000:82:00.0 reporter fw

.. note:: This command can run only on the PF which has fw tracer ownership, running it on other PF or any VF will return "Operation not permitted".

fw fatal reporter

The fw fatal reporter implements dump and recover callbacks. It follows fatal errors indications by CR-space dump and recover flow. The CR-space dump uses vsc interface which is valid even if the FW command interface is not functional, which is the case in most FW fatal errors. The recover function runs recover flow which reloads the driver and triggers fw reset if needed. On firmware error, the health buffer is dumped into the dmesg. The log level is derived from the error's severity (given in health buffer).

User commands examples:

  • Run fw recover flow manually::

    $ devlink health recover pci/0000:82:00.0 reporter fw_fatal

  • Read FW CR-space dump if already stored or trigger new one::

    $ devlink health dump show pci/0000:82:00.1 reporter fw_fatal

.. note:: This command can run only on PF.

vnic reporter

The vnic reporter implements only the diagnose callback. It is responsible for querying the vnic diagnostic counters from fw and displaying them in realtime.

Description of the vnic counters:

  • total_error_queues number of queues in an error state due to an async error or errored command.
  • send_queue_priority_update_flow number of QP/SQ priority/SL update events.
  • cq_overrun number of times CQ entered an error state due to an overflow.
  • async_eq_overrun number of times an EQ mapped to async events was overrun.
  • comp_eq_overrun number of times an EQ mapped to completion events was overrun.
  • quota_exceeded_command number of commands issued and failed due to quota exceeded.
  • invalid_command number of commands issued and failed dues to any reason other than quota exceeded.
  • nic_receive_steering_discard number of packets that completed RX flow steering but were discarded due to a mismatch in flow table.
  • generated_pkt_steering_fail number of packets generated by the VNIC experiencing unexpected steering failure (at any point in steering flow).
  • handled_pkt_steering_fail number of packets handled by the VNIC experiencing unexpected steering failure (at any point in steering flow owned by the VNIC, including the FDB for the eswitch owner).

User commands examples:

  • Diagnose PF/VF vnic counters::

      $ devlink health diagnose pci/0000:82:00.1 reporter vnic

  • Diagnose representor vnic counters (performed by supplying devlink port of the representor, which can be obtained via devlink port command)::

      $ devlink health diagnose pci/0000:82:00.1/65537 reporter vnic

.. note:: This command can run over all interfaces such as PF/VF and representor ports.