=============
Different PMDs may require different kernel drivers in order to work properly.
-Depends on the PMD being used, a corresponding kernel driver should be load
-and bind to the network ports.
+Depending on the PMD being used, a corresponding kernel driver should be loaded,
+and network ports should be bound to that driver.
-UIO
----
+VFIO
+----
-A small kernel module to set up the device, map device memory to user-space and register interrupts.
-In many cases, the standard ``uio_pci_generic`` module included in the Linux kernel
-can provide the uio capability. This module can be loaded using the command:
+VFIO is a robust and secure driver that relies on IOMMU protection.
+To make use of VFIO, the ``vfio-pci`` module must be loaded:
.. code-block:: console
- sudo modprobe uio_pci_generic
+ sudo modprobe vfio-pci
-.. note::
+VFIO kernel is usually present by default in all distributions,
+however please consult your distributions documentation to make sure that is the case.
- ``uio_pci_generic`` module doesn't support the creation of virtual functions.
+For DMA mapping of either external memory or hugepages, VFIO interface is used.
+VFIO does not support partial unmap of once mapped memory. Hence DPDK's memory is
+mapped in hugepage granularity or system page granularity. Number of DMA
+mappings is limited by kernel with user locked memory limit of a process (rlimit)
+for system/hugepage memory. Another per-container overall limit applicable both
+for external memory and system memory was added in kernel 5.1 defined by
+VFIO module parameter ``dma_entry_limit`` with a default value of 64K.
+When application is out of DMA entries, these limits need to be adjusted to
+increase the allowed limit.
-As an alternative to the ``uio_pci_generic``, there is the ``igb_uio`` module
-which can be found in the repository `dpdk-kmods <http://git.dpdk.org/dpdk-kmods>`_.
-It can be loaded as shown below:
+Since Linux version 5.7,
+the ``vfio-pci`` module supports the creation of virtual functions.
+After the PF is bound to ``vfio-pci`` module,
+the user can create the VFs using the ``sysfs`` interface,
+and these VFs will be bound to ``vfio-pci`` module automatically.
-.. code-block:: console
+When the PF is bound to ``vfio-pci``,
+by default it will have a randomly generated VF token.
+For security reasons, this token is write only,
+so the user cannot read it from the kernel directly.
+To access the VFs, the user needs to create a new token,
+and use it to initialize both VF and PF devices.
+The tokens are in UUID format,
+so any UUID generation tool can be used to create a new token.
+
+This VF token can be passed to DPDK by using EAL parameter ``--vfio-vf-token``.
+The token will be used for all PF and VF ports within the application.
+
+#. Generate the VF token by uuid command
+
+ .. code-block:: console
+
+ 14d63f20-8445-11ea-8900-1f9ce7d5650d
+
+#. Load the ``vfio-pci`` module with ``enable_sriov`` parameter set
+
+ .. code-block:: console
+
+ sudo modprobe vfio-pci enable_sriov=1
+
+#. Bind the PCI devices to ``vfio-pci`` driver
- sudo modprobe uio
- sudo insmod igb_uio.ko
+ .. code-block:: console
+
+ ./usertools/dpdk-devbind.py -b vfio-pci 0000:86:00.0
+
+#. Create the desired number of VF devices
+
+ .. code-block:: console
+
+ echo 2 > /sys/bus/pci/devices/0000:86:00.0/sriov_numvfs
+
+#. Start the DPDK application that will manage the PF device
+
+ .. code-block:: console
+
+ <build_dir>/app/dpdk-testpmd -l 22-25 -n 4 -a 86:00.0 \
+ --vfio-vf-token=14d63f20-8445-11ea-8900-1f9ce7d5650d --file-prefix=pf -- -i
+
+#. Start the DPDK application that will manage the VF device
+
+ .. code-block:: console
+
+ <build_dir>/app/dpdk-testpmd -l 26-29 -n 4 -a 86:02.0 \
+ --vfio-vf-token=14d63f20-8445-11ea-8900-1f9ce7d5650d --file-prefix=vf0 -- -i
+
+To make use of full VFIO functionality,
+both kernel and BIOS must support and be configured
+to use IO virtualization (such as Intel® VT-d).
.. note::
- If UEFI secure boot is enabled, the Linux kernel may disallow the use of
- UIO on the system. Therefore, devices for use by DPDK should be bound to the
- ``vfio-pci`` kernel module rather than any UIO-based module.
- For more details see :ref:`linux_gsg_binding_kernel` below.
+ Linux versions earlier than version 3.6 do not support VFIO.
.. note::
- If the devices used for DPDK are bound to the ``uio_pci_generic`` kernel module,
- please make sure that the IOMMU is disabled or passthrough. One can add
- ``intel_iommu=off`` or ``amd_iommu=off`` or ``intel_iommu=on iommu=pt`` in GRUB
- command line on x86_64 systems, or add ``iommu.passthrough=1`` on aarch64 system.
+ Linux versions earlier than version 5.7 do not support the creation of
+ virtual functions within the VFIO framework.
-Since DPDK release 1.7 onward provides VFIO support, use of UIO is optional
-for platforms that support using VFIO.
+.. note::
-VFIO
-----
+ In most cases, specifying "iommu=on" as kernel parameter should be enough to
+ configure the Linux kernel to use IOMMU.
-A more robust and secure driver in compare to the ``UIO``, relying on IOMMU protection.
-To make use of VFIO, the ``vfio-pci`` module must be loaded:
+For proper operation of VFIO when running DPDK applications as a non-privileged user, correct permissions should also be set up.
+For more information, please refer to :ref:`Running_Without_Root_Privileges`.
+
+VFIO no-IOMMU mode
+------------------
+
+If there is no IOMMU available on the system, VFIO can still be used,
+but it has to be loaded with an additional module parameter:
.. code-block:: console
- sudo modprobe vfio-pci
+ modprobe vfio enable_unsafe_noiommu_mode=1
-Note that in order to use VFIO, your kernel must support it.
-VFIO kernel modules have been included in the Linux kernel since version 3.6.0 and are usually present by default,
-however please consult your distributions documentation to make sure that is the case.
+Alternatively, one can also enable this option in an already loaded kernel module:
-The ``vfio-pci`` module since Linux version 5.7 supports the creation of virtual
-functions. After the PF is bound to vfio-pci module, the user can create the VFs
-by sysfs interface, and these VFs are bound to vfio-pci module automatically.
+.. code-block:: console
-When the PF is bound to vfio-pci, it has initial VF token generated by random. For
-security reason, this token is write only, the user can't read it from the kernel
-directly. To access the VF, the user needs to start the PF with token parameter to
-setup a VF token in UUID format, then the VF can be accessed with this new token.
+ echo 1 > /sys/module/vfio/parameters/enable_unsafe_noiommu_mode
-Since the ``vfio-pci`` module uses the VF token as internal data to provide the
-collaboration between SR-IOV PF and VFs, so DPDK can use the same VF token for all
-PF devices which bound to one application. This VF token can be specified by the EAL
-parameter ``--vfio-vf-token``.
+After that, VFIO can be used with hardware devices as usual.
-.. code-block:: console
+.. note::
- 1. Generate the VF token by uuid command
- 14d63f20-8445-11ea-8900-1f9ce7d5650d
+ It may be required to unload all VFIO related-modules before probing
+ the module again with ``enable_unsafe_noiommu_mode=1`` parameter.
- 2. sudo modprobe vfio-pci enable_sriov=1
+.. warning::
- 2. ./usertools/dpdk-devbind.py -b vfio-pci 0000:86:00.0
+ Since no-IOMMU mode forgoes IOMMU protection, it is inherently unsafe.
+ That said, 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.
- 3. echo 2 > /sys/bus/pci/devices/0000:86:00.0/sriov_numvfs
+UIO
+---
- 4. Start the PF:
- <build_dir>/app/dpdk-testpmd -l 22-25 -n 4 -w 86:00.0 \
- --vfio-vf-token=14d63f20-8445-11ea-8900-1f9ce7d5650d --file-prefix=pf -- -i
+In situations where using VFIO is not an option, there are alternative drivers one can use.
+In many cases, the standard ``uio_pci_generic`` module included in the Linux kernel
+can be used as a substitute for VFIO. This module can be loaded using the command:
- 5. Start the VF:
- <build_dir>/app/dpdk-testpmd -l 26-29 -n 4 -w 86:02.0 \
- --vfio-vf-token=14d63f20-8445-11ea-8900-1f9ce7d5650d --file-prefix=vf0 -- -i
+.. code-block:: console
-Also, to use VFIO, both kernel and BIOS must support and be configured to use IO virtualization (such as Intel® VT-d).
+ sudo modprobe uio_pci_generic
.. note::
- ``vfio-pci`` module doesn't support the creation of virtual functions before Linux version 5.7.
+ ``uio_pci_generic`` module doesn't support the creation of virtual functions.
-For proper operation of VFIO when running DPDK applications as a non-privileged user, correct permissions should also be set up.
-This can be done by using the DPDK setup script (called dpdk-setup.sh and located in the usertools directory).
+As an alternative to the ``uio_pci_generic``, there is the ``igb_uio`` module
+which can be found in the repository `dpdk-kmods <http://git.dpdk.org/dpdk-kmods>`_.
+It can be loaded as shown below:
+
+.. code-block:: console
+
+ sudo modprobe uio
+ sudo insmod igb_uio.ko
.. note::
- 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.
+ If UEFI secure boot is enabled,
+ the Linux kernel may disallow the use of UIO on the system.
+ Therefore, devices for use by DPDK should be bound to the ``vfio-pci`` kernel module
+ rather than any UIO-based module.
+ For more details see :ref:`linux_gsg_binding_kernel` below.
+
+.. note::
+
+ If the devices used for DPDK are bound to the ``uio_pci_generic`` kernel module,
+ please make sure that the IOMMU is disabled or is in passthrough mode.
+ One can add ``intel_iommu=off`` or ``amd_iommu=off`` or ``intel_iommu=on iommu=pt``
+ in GRUB command line on x86_64 systems,
+ or add ``iommu.passthrough=1`` on aarch64 systems.
+
+.. note::
+
+ Using UIO drivers is inherently unsafe due to this method lacking IOMMU protection,
+ and can only be done by root user.
.. _bifurcated_driver:
.. note::
- 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.
+ PMDs which use the bifurcated driver should not be unbound from their kernel drivers.
+ This section is for PMDs which use the UIO or VFIO drivers.
As of release 1.4, DPDK applications no longer automatically unbind all supported network ports from the kernel driver in use.
-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
-``uio_pci_generic``, ``igb_uio`` or ``vfio-pci`` module before the application is run.
+Instead, in case the PMD being used use the VFIO or UIO drivers,
+all ports that are to be used by a DPDK application must be bound to
+the ``vfio-pci``, ``uio_pci_generic``, or ``igb_uio`` module
+before the application is run.
For such PMDs, any network ports under Linux* control will be ignored and cannot be used by the application.
-To bind ports to the ``uio_pci_generic``, ``igb_uio`` or ``vfio-pci`` module for DPDK use,
-and then subsequently return ports to Linux* control,
-a utility script called dpdk-devbind.py is provided in the usertools subdirectory.
+To bind ports to the ``vfio-pci``, ``uio_pci_generic`` or ``igb_uio`` module
+for DPDK use, or to return ports to Linux control,
+a utility script called ``dpdk-devbind.py`` is provided in the ``usertools`` subdirectory.
This utility can be used to provide a view of the current state of the network ports on the system,
-and to bind and unbind those ports from the different kernel modules, including the uio and vfio modules.
+and to bind and unbind those ports from the different kernel modules,
+including the VFIO and UIO modules.
The following are some examples of how the script can be used.
-A full description of the script and its parameters can be obtained by calling the script with the ``--help`` or ``--usage`` options.
-Note that the uio or vfio kernel modules to be used, should be loaded into the kernel before
-running the ``dpdk-devbind.py`` script.
+A full description of the script and its parameters can be obtained
+by calling the script with the ``--help`` or ``--usage`` options.
+Note that the UIO or VFIO kernel modules to be used,
+should be loaded into the kernel before running the ``dpdk-devbind.py`` script.
.. warning::
- Due to the way VFIO works, there are certain limitations to which devices can be used with VFIO.
- Mainly it comes down to how IOMMU groups work.
- Any Virtual Function device can be used with VFIO on its own, but physical devices will require either all ports bound to VFIO,
- or some of them bound to VFIO while others not being bound to anything at all.
+ Due to the way VFIO works, there are certain limitations
+ to which devices can be used with VFIO.
+ Mainly it comes down to how IOMMU groups work.
+ Any Virtual Function device can usually be used with VFIO on its own,
+ but physical devices may require either all ports bound to VFIO,
+ or some of them bound to VFIO while others not being bound to anything at all.
- 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.
- Therefore, the bridge driver should also be unbound from the bridge PCI device for VFIO to work with devices behind the bridge.
+ 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.
+ Therefore, the bridge driver should also be unbound from the bridge PCI device
+ for VFIO to work with devices behind the bridge.
.. warning::
- While any user can run the dpdk-devbind.py script to view the status of the network ports,
- binding or unbinding network ports requires root privileges.
+ While any user can run the ``dpdk-devbind.py`` script
+ to view the status of the network ports,
+ binding or unbinding network ports requires root privileges.
To see the status of all network ports on the system:
.. code-block:: console
./usertools/dpdk-devbind.py --bind=ixgbe 82:00.0
+
+Troubleshooting VFIO
+--------------------
+
+In certain situations, using ``dpdk-devbind.py`` script
+to bind a device to VFIO driver may fail.
+The first place to check is the kernel messages:
+
+.. code-block:: console
+
+ dmesg | tail
+ ...
+ [ 1297.875090] vfio-pci: probe of 0000:31:00.0 failed with error -22
+ ...
+
+In most cases, the ``error -22`` indicates that the VFIO subsystem
+could not be enabled because there is no IOMMU support.
+
+To check whether the kernel has been booted with correct parameters,
+one can check the kernel command-line:
+
+.. code-block:: console
+
+ cat /proc/cmdline
+
+Please refer to earlier sections on how to configure kernel parameters
+correctly for your system.
+
+If the kernel is configured correctly, one also has to make sure that
+the BIOS configuration has virtualization features (such as Intel® VT-d).
+There is no standard way to check if the platform is configured correctly,
+so please check with your platform documentation to see if it has such features,
+and how to enable them.
+
+In certain distributions, default kernel configuration is such that
+the no-IOMMU mode is disabled altogether at compile time.
+This can be checked in the boot configuration of your system:
+
+.. code-block:: console
+
+ cat /boot/config-$(uname -r) | grep NOIOMMU
+ # CONFIG_VFIO_NOIOMMU is not set
+
+If ``CONFIG_VFIO_NOIOMMU`` is not enabled in the kernel configuration,
+VFIO driver will not support the no-IOMMU mode,
+and other alternatives (such as UIO drivers) will have to be used.
git.droids-corp.org / dpdk.git / blobdiff