ixgbevf Linux* Virtual Function (VF) Driver for Intel(R) Ethernet Network
Connection
================================================================================

July 29, 2021

================================================================================

Contents
--------

- Overview
- Identifying Your Adapter
- Building and Installation
- Additional Configurations
- Known Issues
- Support
- License


Overview
========
This virtual function driver supports kernel versions 2.6.x and newer.

The associated Physical Function (PF) driver for this driver is ixgbe.

The MTU size set on a VF should match the MTU size set on the PF. A mismatch in
MTU sizes may cause unexpected results.

SR-IOV requires the correct platform and OS support.

The guest OS loading this driver must support MSI-X interrupts.

This driver is only supported as a loadable module at this time. Intel is not
supplying patches against the kernel source to allow for static linking of the
drivers.


For questions related to hardware requirements, refer to the documentation
supplied with your Intel adapter. All hardware requirements listed apply to use
with Linux.

Driver information can be obtained using ethtool, lspci, and ip. Instructions
on updating ethtool can be found in the section Additional Configurations later
in this document.

VLANs: There is a limit of a total of 64 shared VLANs to 1 or more VFs.

A version of the driver may already be included by your distribution and/or the
kernel.org kernel.


Related Documentation
=====================

See the "Intel(R) Ethernet Adapters and Devices User Guide" for additional
information on features. It is available on the Intel website at either of the
following:

- https://cdrdv2.intel.com/v1/dl/getContent/705831
-
https://www.intel.com/content/www/us/en/download/19373/adapter-user-guide-for-in
tel-ethernet-adapters.html


Identifying Your Adapter
========================
For information on how to identify your adapter, and for the latest Intel
network drivers, refer to the Intel Support website:
http://www.intel.com/support


Building and Installation
=========================

To manually build the driver
----------------------------
1. Move the virtual function driver tar file to the directory of your choice.
   For example, use '/home/username/ixgbevf' or '/usr/local/src/ixgbevf'.

2. Untar/unzip the archive, where <x.x.x> is the version number for the
   driver tar file:

   # tar zxf ixgbevf-<x.x.x>.tar.gz

3. Change to the driver src directory, where <x.x.x> is the version number
   for the driver tar:

   # cd ixgbevf-<x.x.x>/src/

4. Compile the driver module:

   # make install

   The binary will be installed as:
   /lib/modules/<KERNEL
VER>/updates/drivers/net/ethernet/intel/ixgbevf/ixgbevf.ko

   The install location listed above is the default location. This may differ
   for various Linux distributions.

5. Load the module using the modprobe command.

   To check the version of the driver and then load it:

   # modinfo ixgbevf
   # modprobe ixgbevf

   Alternately, make sure that any older ixgbevf drivers are removed from the
   kernel before loading the new module:

   # rmmod ixgbevf; modprobe ixgbevf

6. Assign an IP address to the interface by entering the following,
   where <ethX> is the interface name that was shown in dmesg after modprobe:

   # ip address add <IP_address>/<netmask bits> dev <ethX>

7. Verify that the interface works. Enter the following, where IP_address
   is the IP address for another machine on the same subnet as the interface
   that is being tested:

   # ping <IP_address>

Note: For certain distributions like (but not limited to) Red Hat Enterprise
Linux 7 and Ubuntu, once the driver is installed, you may need to update the
initrd/initramfs file to prevent the OS loading old versions of the ixgbevf
driver.
   For Red Hat distributions:
	# dracut --force

   For Ubuntu:
	# update-initramfs -u

 
To build a binary RPM package of this driver
--------------------------------------------
Note: RPM functionality has only been tested in Red Hat distributions.

1. Run the following command, where <x.x.x> is the version number for the
   driver tar file.

   # rpmbuild -tb ixgbevf-<x.x.x>.tar.gz

   NOTE: For the build to work properly, the currently running kernel MUST
   match the version and configuration of the installed kernel sources. If
   you have just recompiled the kernel, reboot the system before building.

2. After building the RPM, the last few lines of the tool output contain the
   location of the RPM file that was built. Install the RPM with one of the
   following commands, where <RPM> is the location of the RPM file:

   # rpm -Uvh <RPM>
       or
   # dnf/yum localinstall <RPM>

NOTES:
- To compile the driver on some kernel/arch combinations, you may need to
install a package with the development version of libelf (e.g. libelf-dev,
libelf-devel, elfutils-libelf-devel).
- When compiling an out-of-tree driver, details will vary by distribution.
However, you will usually need a kernel-devel RPM or some RPM that provides the
kernel headers at a minimum. The RPM kernel-devel will usually fill in the link
at /lib/modules/'uname -r'/build.


Command Line Parameters
=======================
If the driver is built as a module, enter optional parameters on the command
line with the following syntax:

# modprobe ixgbevf [<option>=<VAL1>,<VAL2>,...]

There needs to be a <VAL#> for each network port in the system supported by
this driver. The values will be applied to each instance, in function order.
For example:


- The default value for each parameter is generally the recommended setting,
unless otherwise noted.


InterruptThrottleRate
---------------------
Valid Range:
0=off
1=dynamic
<min_ITR>-<max_ITR>
Use ethtool to control InterruptThrottleRate, as shown below:

# ethtool -C <ethX> rx-usecs N
  where N is the time in microseconds between each interrupt.

Interrupt Throttle Rate controls the number of interrupts each interrupt
vector can generate per second. Increasing ITR lowers latency at the cost of
increased CPU utilization, though it may help throughput in some circumstances.
0 = Setting InterruptThrottleRate to 0 turns off any interrupt moderation
  and may improve small packet latency. However, this is generally not
  suitable for bulk throughput traffic due to the increased CPU utilization
  of the higher interrupt rate.
  NOTES:
  - On 82599, and X540, and X550-based adapters, disabling InterruptThrottleRate
    will also result in the driver disabling HW RSC.
  - On 82598-based adapters, disabling InterruptThrottleRate will also
    result in disabling LRO (Large Receive Offloads).
1 = Setting InterruptThrottleRate to Dynamic mode attempts to moderate
  interrupts per vector while maintaining very low latency. This can
  sometimes cause extra CPU utilization. If planning on deploying ixgbevf
  in a latency sensitive environment, this parameter should be considered.
<min_ITR>-<max_ITR> = 956-488281
  Setting InterruptThrottleRate to a value greater or equal to <min_ITR>
  will program the adapter to send at most that many interrupts
  per second, even if more packets have come in. This reduces interrupt load
  on the system and can lower CPU utilization under heavy load, but will
  increase latency as packets are not processed as quickly.



Additional Features and Configurations
======================================

Configuring the Driver on Different Distributions
-------------------------------------------------
Configuring a network driver to load properly when the system is started is
distribution dependent. Typically, the configuration process involves adding an
alias line to /etc/modules.conf or /etc/modprobe.conf as well as editing other
system startup scripts and/or configuration files. Many popular Linux
distributions ship with tools to make these changes for you. To learn the
proper way to configure a network device for your system, refer to your
distribution documentation. If during this process you are asked for the driver
or module name, the name for the Base Driver is ixgbevf.

For example, if you install the ixgbevf driver for two adapters (eth0 and eth1)
and want to set the interrupt mode to MSI-X and MSI, respectively, add the
following to modules.conf or /etc/modprobe.conf:
  alias eth0 ixgbevf
  alias eth1 ixgbevf
  options ixgbevf IntMode=2,1


Viewing Link Messages
---------------------
Link messages will not be displayed to the console if the distribution is
restricting system messages. In order to see network driver link messages on
your console, set dmesg to eight by entering the following:

# dmesg -n 8

NOTE: This setting is not saved across reboots.


ethtool
-------
The driver utilizes the ethtool interface for driver configuration and
diagnostics, as well as displaying statistical information. The latest ethtool
version is required for this functionality. Download it at:
https://kernel.org/pub/software/network/ethtool/


MACVLAN
-------
This driver supports MACVLAN. Kernel support for MACVLAN can be tested by
checking if the MACVLAN driver is loaded. You can run 'lsmod | grep macvlan' to
see if the MACVLAN driver is loaded or run 'modprobe macvlan' to try to load
the MACVLAN driver.

NOTE:
- In passthru mode, you can only set up one MACVLAN device. It will inherit the
MAC address of the underlying PF (Physical Function) device.


NAPI
----
This driver supports NAPI (Rx polling mode). For more information on NAPI, see
https://docs.kernel.org/networking/napi.html.


Known Issues/Troubleshooting
============================

Hardware Issues
---------------
For known hardware and troubleshooting issues, either refer to the "Release
Notes" in your User Guide, or for more detailed information, go to
http://www.intel.com.

In the search box enter your devices controller ID followed by "spec update"
(i.e., 82599 spec update). The specification update file has complete
information on known hardware issues.


Software Issues
---------------
NOTE: After installing the driver, if your Intel Ethernet Network Connection
is not working, verify that you have installed the correct driver.


Compiling the Driver
--------------------
When trying to compile the driver by running make install, the following error
may occur: "Linux kernel source not configured - missing version.h"

To solve this issue, create the version.h file by going to the Linux source
tree and entering:

# make include/linux/version.h


MAC address of Virtual Function changes unexpectedly
----------------------------------------------------
If a Virtual Function's MAC address is not assigned in the host, then the VF
(virtual function) driver will use a random MAC address. This random MAC
address may change each time the VF driver is reloaded. You can assign a static
MAC address in the host machine. This static MAC address will survive a VF
driver reload.


dmesg: Unable to start - perhaps the PF Driver isn't up yet
-----------------------------------------------------------
This message is posted when the PF interface is down when you try to change the
number of Tx or Rx queues on the VF interface. To resolve the issue, bring the
PF interface up and reload the VF driver.


SR-IOV virtual functions have identical MAC addresses
-----------------------------------------------------
When you create multiple SR-IOV virtual functions, the VFs may have identical
MAC addresses. Only one VF will pass traffic, and all traffic on other VFs with
identical MAC addresses will fail. This is related to the
"MACAddressPolicy=persistent" setting in
/usr/lib/systemd/network/99-default.link.

To resolve this issue, edit the /usr/lib/systemd/network/99-default.link file
and change the MACAddressPolicy line to "MACAddressPolicy=none". For more
information, see the systemd.link man page.


Multiple Interfaces on Same Ethernet Broadcast Network
------------------------------------------------------
Due to the default ARP behavior on Linux, it is not possible to have one system
on two IP networks in the same Ethernet broadcast domain (non-partitioned
switch) behave as expected. All Ethernet interfaces will respond to IP traffic
for any IP address assigned to the system. This results in unbalanced receive
traffic.

If you have multiple interfaces in a server, either turn on ARP filtering by
entering the following:

# echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter

This only works if your kernel's version is higher than 2.4.5.

NOTE: This setting is not saved across reboots. The configuration change can be
made permanent by adding the following line to the file /etc/sysctl.conf:

  net.ipv4.conf.all.arp_filter = 1

Another alternative is to install the interfaces in separate broadcast domains
(either in different switches or in a switch partitioned to VLANs).


Build Error with Asianux 3.0 - Redefinition of typedef 'irq_handler_t'
----------------------------------------------------------------------
Some systems may experience build issues due to the redefinition of
irq_handler_t. To resolve this issue, build the driver (step 4 above) using the
command:

# make CFLAGS_EXTRA=-DAX_RELEASE_CODE=1 install


Rx Page Allocation Errors
-------------------------
'Page allocation failure. order:0' errors may occur under stress with kernels
2.6.25 and newer. This is caused by the way the Linux kernel reports this
stressed condition.


Host May Reboot after Removing PF when VF is Active in Guest
------------------------------------------------------------
Using kernel versions earlier than 3.2, do not unload the PF driver with
active VFs. Doing this will cause your VFs to stop working until you reload
the PF driver and may cause a spontaneous reboot of your system.

Prior to unloading the PF driver, you must first ensure that all VFs are
no longer active. Do this by shutting down all VMs and unloading the VF driver.


Support
=======
For general information, go to the Intel support website at:
http://www.intel.com/support/

or the Intel Wired Networking project hosted by Sourceforge at:
http://sourceforge.net/projects/e1000

If an issue is identified with the released source code on a supported kernel
with a supported adapter, email the specific information related to the issue
to e1000-devel@lists.sf.net.


License
=======
This program is free software; you can redistribute it and/or modify it under
the terms and conditions of the GNU General Public License, version 2, as
published by the Free Software Foundation.

This program is distributed in the hope it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 51 Franklin
St - Fifth Floor, Boston, MA 02110-1301 USA.

The full GNU General Public License is included in this distribution in the
file called "COPYING".

Copyright(c) 1999 - 2021 Intel Corporation.


Trademarks
==========
Intel is a trademark or registered trademark of Intel Corporation or its
subsidiaries in the United States and/or other countries.

* Other names and brands may be claimed as the property of others.