38. NFP poll mode driver library

Netronome’s sixth generation of flow processors pack 216 programmable cores and over 100 hardware accelerators that uniquely combine packet, flow, security and content processing in a single device that scales up to 400-Gb/s.

This document explains how to use DPDK with the Netronome Poll Mode Driver (PMD) supporting Netronome’s Network Flow Processor 6xxx (NFP-6xxx) and Netronome’s Flow Processor 4xxx (NFP-4xxx).

NFP is a SRIOV capable device and the PMD driver supports the physical function (PF) and the virtual functions (VFs).

38.1. Dependencies

Before using the Netronome’s DPDK PMD some NFP configuration, which is not related to DPDK, is required. The system requires installation of Netronome’s BSP (Board Support Package) along with a specific NFP firmware application. Netronome’s NSP ABI version should be 0.20 or higher.

If you have a NFP device you should already have the code and documentation for this configuration. Contact support@netronome.com to obtain the latest available firmware.

The NFP Linux netdev kernel driver for VFs has been a part of the vanilla kernel since kernel version 4.5, and support for the PF since kernel version 4.11. Support for older kernels can be obtained on Github at https://github.com/Netronome/nfp-drv-kmods along with the build instructions.

NFP PMD needs to be used along with UIO igb_uio or VFIO (vfio-pci) Linux kernel driver.

38.2. Building the software

Netronome’s PMD code is provided in the drivers/net/nfp directory. Although NFP PMD has Netronome´s BSP dependencies, it is possible to compile it along with other DPDK PMDs even if no BSP was installed previously. Of course, a DPDK app will require such a BSP installed for using the NFP PMD, along with a specific NFP firmware application.

Default PMD configuration is at the common_linux configuration file:

  • CONFIG_RTE_LIBRTE_NFP_PMD=y

Once the DPDK is built all the DPDK apps and examples include support for the NFP PMD.

38.3. Driver compilation and testing

Refer to the document compiling and testing a PMD for a NIC for details.

38.4. Using the PF

NFP PMD supports using the NFP PF as another DPDK port, but it does not have any functionality for controlling VFs. In fact, it is not possible to use the PMD with the VFs if the PF is being used by DPDK, that is, with the NFP PF bound to igb_uio or vfio-pci kernel drivers. Future DPDK versions will have a PMD able to work with the PF and VFs at the same time and with the PF implementing VF management along with other PF-only functionalities/offloads.

The PMD PF has extra work to do which will delay the DPDK app initialization like uploading the firmware and configure the Link state properly when starting or stopping a PF port. Since DPDK 18.05 the firmware upload happens when a PF is initialized, which was not always true with older DPDK versions.

Depending on the Netronome product installed in the system, firmware files should be available under /lib/firmware/netronome. DPDK PMD supporting the PF looks for a firmware file in this order:

  1. First try to find a firmware image specific for this device using the NFP serial number:

    serial-00-15-4d-12-20-65-10-ff.nffw

  2. Then try the PCI name:

    pci-0000:04:00.0.nffw

  3. Finally try the card type and media:

    nic_AMDA0099-0001_2x25.nffw

Netronome’s software packages install firmware files under /lib/firmware/netronome to support all the Netronome’s SmartNICs and different firmware applications. This is usually done using file names based on SmartNIC type and media and with a directory per firmware application. Options 1 and 2 for firmware filenames allow more than one SmartNIC, same type of SmartNIC or different ones, and to upload a different firmware to each SmartNIC.

38.5. PF multiport support

Some NFP cards support several physical ports with just one single PCI device. The DPDK core is designed with a 1:1 relationship between PCI devices and DPDK ports, so NFP PMD PF support requires handling the multiport case specifically. During NFP PF initialization, the PMD will extract the information about the number of PF ports from the firmware and will create as many DPDK ports as needed.

Because the unusual relationship between a single PCI device and several DPDK ports, there are some limitations when using more than one PF DPDK port: there is no support for RX interrupts and it is not possible either to use those PF ports with the device hotplug functionality.

38.6. PF multiprocess support

Due to how the driver needs to access the NFP through a CPP interface, which implies to use specific registers inside the chip, the number of secondary processes with PF ports is limited to only one.

This limitation will be solved in future versions but having basic multiprocess support is important for allowing development and debugging through the PF using a secondary process which will create a CPP bridge for user space tools accessing the NFP.

38.7. System configuration

  1. Enable SR-IOV on the NFP device: The current NFP PMD supports the PF and the VFs on a NFP device. However, it is not possible to work with both at the same time because the VFs require the PF being bound to the NFP PF Linux netdev driver. Make sure you are working with a kernel with NFP PF support or get the drivers from the above Github repository and follow the instructions for building and installing it.

    VFs need to be enabled before they can be used with the PMD. Before enabling the VFs it is useful to obtain information about the current NFP PCI device detected by the system:

    lspci -d19ee:

    Now, for example, configure two virtual functions on a NFP-6xxx device whose PCI system identity is “0000:03:00.0”:

    echo 2 > /sys/bus/pci/devices/0000:03:00.0/sriov_numvfs

    The result of this command may be shown using lspci again:

    lspci -d19ee: -k

    Two new PCI devices should appear in the output of the above command. The -k option shows the device driver, if any, that devices are bound to. Depending on the modules loaded at this point the new PCI devices may be bound to nfp_netvf driver.