45. 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), Netronome’s Network Flow Processor 4xxx (NFP-4xxx) and Netronome’s Network Flow Processor 38xx (NFP-38xx).

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

45.1. 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.

45.2. 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.

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

45.3. Driver compilation and testing

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

45.4. 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.

Note

Currently the NFP PMD supports using the PF with Agilio Firmware with NFD3 and Agilio Firmware with NFDk. See https://help.netronome.com/support/solutions for more information on the various firmwares supported by the Netronome Agilio CX smartNIC.

45.5. PF multiport support

The NFP PMD can work with up to 8 ports on the same PF device. The number of available ports is firmware and hardware dependent, and the driver looks for a firmware symbol during initialization to know how many can be used.

DPDK apps work with ports, and a port is usually a PF or a VF PCI device. However, with the NFP PF multiport there is just one PF PCI device. Supporting this particular configuration requires the PMD to create ports in a special way, although once they are created, DPDK apps should be able to use them as normal PCI ports.

NFP ports belonging to same PF can be seen inside PMD initialization with a suffix added to the PCI ID: wwww:xx:yy.z_portn. For example, a PF with PCI ID 0000:03:00.0 and four ports is seen by the PMD code as:

0000:03:00.0_port0
0000:03:00.0_port1
0000:03:00.0_port2
0000:03:00.0_port3

Note

There are some limitations with multiport support: RX interrupts and device hot-plugging are not supported.

45.6. 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.

45.7. 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.

45.8. Flow offload

Use the flower firmware application, some type of Netronome’s SmartNICs can offload the flow into cards.

The flower firmware application requires the PMD running two services:

  • PF vNIC service: handling the feedback traffic.

  • ctrl vNIC service: communicate between PMD and firmware through control message.

To achieve the offload of flow, the representor ports are exposed to OVS. The flower firmware application support representor port for VF and physical port. There will always exist a representor port for each physical port, and the number of the representor port for VF is specified by the user through parameter.

In the Rx direction, the flower firmware application will prepend the input port information into metadata for each packet which can’t offloaded. The PF vNIC service will keep polling packets from the firmware, and multiplex them to the corresponding representor port.

In the Tx direction, the representor port will prepend the output port information into metadata for each packet, and then send it to firmware through PF vNIC.

The ctrl vNIC service handling various control message, like the creation and configuration of representor port, the pattern and action of flow rules, the statistics of flow rules, and so on.