1 .. SPDX-License-Identifier: BSD-3-Clause
2 Copyright(c) 2010-2015 Intel Corporation.
3 Copyright 2017 Mellanox Technologies, Ltd
6 .. _linux_gsg_linux_drivers:
11 Different PMDs may require different kernel drivers in order to work properly.
12 Depends on the PMD being used, a corresponding kernel driver should be load
13 and bind to the network ports.
18 A small kernel module to set up the device, map device memory to user-space and register interrupts.
19 In many cases, the standard ``uio_pci_generic`` module included in the Linux kernel
20 can provide the uio capability. This module can be loaded using the command:
22 .. code-block:: console
24 sudo modprobe uio_pci_generic
28 ``uio_pci_generic`` module doesn't support the creation of virtual functions.
30 As an alternative to the ``uio_pci_generic``, there is the ``igb_uio`` module
31 which can be found in the repository `dpdk-kmods <http://git.dpdk.org/dpdk-kmods>`_.
32 It can be loaded as shown below:
34 .. code-block:: console
37 sudo insmod igb_uio.ko
41 If UEFI secure boot is enabled, the Linux kernel may disallow the use of
42 UIO on the system. Therefore, devices for use by DPDK should be bound to the
43 ``vfio-pci`` kernel module rather than any UIO-based module.
44 For more details see :ref:`linux_gsg_binding_kernel` below.
48 If the devices used for DPDK are bound to the ``uio_pci_generic`` kernel module,
49 please make sure that the IOMMU is disabled or passthrough. One can add
50 ``intel_iommu=off`` or ``amd_iommu=off`` or ``intel_iommu=on iommu=pt`` in GRUB
51 command line on x86_64 systems, or add ``iommu.passthrough=1`` on aarch64 system.
53 Since DPDK release 1.7 onward provides VFIO support, use of UIO is optional
54 for platforms that support using VFIO.
59 A more robust and secure driver in compare to the ``UIO``, relying on IOMMU protection.
60 To make use of VFIO, the ``vfio-pci`` module must be loaded:
62 .. code-block:: console
64 sudo modprobe vfio-pci
66 Note that in order to use VFIO, your kernel must support it.
67 VFIO kernel modules have been included in the Linux kernel since version 3.6.0 and are usually present by default,
68 however please consult your distributions documentation to make sure that is the case.
70 The ``vfio-pci`` module since Linux version 5.7 supports the creation of virtual
71 functions. After the PF is bound to vfio-pci module, the user can create the VFs
72 by sysfs interface, and these VFs are bound to vfio-pci module automatically.
74 When the PF is bound to vfio-pci, it has initial VF token generated by random. For
75 security reason, this token is write only, the user can't read it from the kernel
76 directly. To access the VF, the user needs to start the PF with token parameter to
77 setup a VF token in UUID format, then the VF can be accessed with this new token.
79 Since the ``vfio-pci`` module uses the VF token as internal data to provide the
80 collaboration between SR-IOV PF and VFs, so DPDK can use the same VF token for all
81 PF devices which bound to one application. This VF token can be specified by the EAL
82 parameter ``--vfio-vf-token``.
84 .. code-block:: console
86 1. Generate the VF token by uuid command
87 14d63f20-8445-11ea-8900-1f9ce7d5650d
89 2. sudo modprobe vfio-pci enable_sriov=1
91 2. ./usertools/dpdk-devbind.py -b vfio-pci 0000:86:00.0
93 3. echo 2 > /sys/bus/pci/devices/0000:86:00.0/sriov_numvfs
96 <build_dir>/app/dpdk-testpmd -l 22-25 -n 4 -w 86:00.0 \
97 --vfio-vf-token=14d63f20-8445-11ea-8900-1f9ce7d5650d --file-prefix=pf -- -i
100 <build_dir>/app/dpdk-testpmd -l 26-29 -n 4 -w 86:02.0 \
101 --vfio-vf-token=14d63f20-8445-11ea-8900-1f9ce7d5650d --file-prefix=vf0 -- -i
103 Also, to use VFIO, both kernel and BIOS must support and be configured to use IO virtualization (such as IntelĀ® VT-d).
107 ``vfio-pci`` module doesn't support the creation of virtual functions before Linux version 5.7.
109 For proper operation of VFIO when running DPDK applications as a non-privileged user, correct permissions should also be set up.
110 This can be done by using the DPDK setup script (called dpdk-setup.sh and located in the usertools directory).
114 VFIO can be used without IOMMU. While this is just as unsafe as using UIO, it does make it possible for the user to keep the degree of device access and programming that VFIO has, in situations where IOMMU is not available.
116 .. _bifurcated_driver:
121 PMDs which use the bifurcated driver co-exists with the device kernel driver.
122 On such model the NIC is controlled by the kernel, while the data
123 path is performed by the PMD directly on top of the device.
125 Such model has the following benefits:
127 - It is secure and robust, as the memory management and isolation
128 is done by the kernel.
129 - It enables the user to use legacy linux tools such as ``ethtool`` or
130 ``ifconfig`` while running DPDK application on the same network ports.
131 - It enables the DPDK application to filter only part of the traffic,
132 while the rest will be directed and handled by the kernel driver.
133 The flow bifurcation is performed by the NIC hardware.
134 As an example, using :ref:`flow_isolated_mode` allows to choose
135 strictly what is received in DPDK.
137 More about the bifurcated driver can be found in
138 `Mellanox Bifurcated DPDK PMD
139 <https://www.dpdk.org/wp-content/uploads/sites/35/2016/10/Day02-Session04-RonyEfraim-Userspace2016.pdf>`__.
141 .. _linux_gsg_binding_kernel:
143 Binding and Unbinding Network Ports to/from the Kernel Modules
144 --------------------------------------------------------------
148 PMDs Which use the bifurcated driver should not be unbind from their kernel drivers. this section is for PMDs which use the UIO or VFIO drivers.
150 As of release 1.4, DPDK applications no longer automatically unbind all supported network ports from the kernel driver in use.
151 Instead, in case the PMD being used use the UIO or VFIO drivers, all ports that are to be used by an DPDK application must be bound to the
152 ``uio_pci_generic``, ``igb_uio`` or ``vfio-pci`` module before the application is run.
153 For such PMDs, any network ports under Linux* control will be ignored and cannot be used by the application.
155 To bind ports to the ``uio_pci_generic``, ``igb_uio`` or ``vfio-pci`` module for DPDK use,
156 and then subsequently return ports to Linux* control,
157 a utility script called dpdk-devbind.py is provided in the usertools subdirectory.
158 This utility can be used to provide a view of the current state of the network ports on the system,
159 and to bind and unbind those ports from the different kernel modules, including the uio and vfio modules.
160 The following are some examples of how the script can be used.
161 A full description of the script and its parameters can be obtained by calling the script with the ``--help`` or ``--usage`` options.
162 Note that the uio or vfio kernel modules to be used, should be loaded into the kernel before
163 running the ``dpdk-devbind.py`` script.
167 Due to the way VFIO works, there are certain limitations to which devices can be used with VFIO.
168 Mainly it comes down to how IOMMU groups work.
169 Any Virtual Function device can be used with VFIO on its own, but physical devices will require either all ports bound to VFIO,
170 or some of them bound to VFIO while others not being bound to anything at all.
172 If your device is behind a PCI-to-PCI bridge, the bridge will then be part of the IOMMU group in which your device is in.
173 Therefore, the bridge driver should also be unbound from the bridge PCI device for VFIO to work with devices behind the bridge.
177 While any user can run the dpdk-devbind.py script to view the status of the network ports,
178 binding or unbinding network ports requires root privileges.
180 To see the status of all network ports on the system:
182 .. code-block:: console
184 ./usertools/dpdk-devbind.py --status
186 Network devices using DPDK-compatible driver
187 ============================================
188 0000:82:00.0 '82599EB 10-GbE NIC' drv=uio_pci_generic unused=ixgbe
189 0000:82:00.1 '82599EB 10-GbE NIC' drv=uio_pci_generic unused=ixgbe
191 Network devices using kernel driver
192 ===================================
193 0000:04:00.0 'I350 1-GbE NIC' if=em0 drv=igb unused=uio_pci_generic *Active*
194 0000:04:00.1 'I350 1-GbE NIC' if=eth1 drv=igb unused=uio_pci_generic
195 0000:04:00.2 'I350 1-GbE NIC' if=eth2 drv=igb unused=uio_pci_generic
196 0000:04:00.3 'I350 1-GbE NIC' if=eth3 drv=igb unused=uio_pci_generic
198 Other network devices
199 =====================
202 To bind device ``eth1``,``04:00.1``, to the ``uio_pci_generic`` driver:
204 .. code-block:: console
206 ./usertools/dpdk-devbind.py --bind=uio_pci_generic 04:00.1
210 .. code-block:: console
212 ./usertools/dpdk-devbind.py --bind=uio_pci_generic eth1
214 To restore device ``82:00.0`` to its original kernel binding:
216 .. code-block:: console
218 ./usertools/dpdk-devbind.py --bind=ixgbe 82:00.0