igbvf Linux* Base Driver for Intel(R) Ethernet Network Connection

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October 7, 2016

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

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Overview
--------

This virtual function driver supports kernel versions 2.6.30 or newer.

This driver supports 82576-based virtual function devices
that can only be activated on kernels that support SR-IOV.

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 ifconfig.
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 32 shared VLANs to 1 or more VFs.



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Identifying Your Adapter
------------------------
For information on how to identify your adapter, go to the Adapter &
Driver ID Guide at:
http://support.intel.com/support/go/network/adapter/proidguide.htm

For the latest Intel network drivers, refer to the
following website and select your adapter.
http://www.intel.com/support


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Building and Installation
-------------------------

To build a binary RPM* package of this driver, run 'rpmbuild -tb
igbvf-<x.x.x>.tar.gz', where <x.x.x> is the version number for the driver tar file.

NOTES:

- 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.
- RPM functionality has only been tested in Red Hat distributions.

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

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

4. Compile the driver module:
   # make install
   The binary will be installed as:
   /lib/modules/<KERNEL VERSION>/updates/drivers/net/ethernet/intel/igbvf/igbvf.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:
   modprobe <igbvf>

   Make sure that any older igbvf drivers are removed from the kernel before
   loading the new module:
   rmmod igbvf; modprobe igbvf

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) RedHat Enterprise
   Linux 7 and Ubuntu, once the driver is installed the initrd/initramfs
   file may need to be updated to prevent the OS loading old versions
   of the igbvf driver. The dracut utility may be used on RedHat
   distributions:
	# dracut --force
   For Ubuntu:
	# update-initramfs -u


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Command Line Parameters
-----------------------
If the driver is built as a module, the following optional parameters are used
by entering them on the command line with the modprobe command using this
syntax:
modprobe igbvf [<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:
modprobe igbvf InterruptThrottleRate=16000,16000

In this case, there are two network ports supported by igbvf in the system.
The default value for each parameter is generally the recommended setting,
unless otherwise noted.

NOTES:
- For more information about the command line parameters, see the application
  note at: http://www.intel.com/design/network/applnots/ap450.htm.
- A descriptor describes a data buffer and attributes related to the data
  buffer. This information is accessed by the hardware.


InterruptThrottleRate
---------------------
Valid Range:
0=off
1=dynamic
3=dynamic conservative
<min_ITR>-<max_ITR>
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 igbvf
  in a latency sensitive environment, this parameter should be considered.
<min_ITR>-<max_ITR> = 100-100000
  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.

 



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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 igbvf.

For example, if you install the igbvf 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 igbvf
alias eth1 igbvf
options igbvf InterruptThrottleRate=3,1


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.


Jumbo Frames
------------
Jumbo Frames support is enabled by changing the Maximum Transmission Unit
(MTU) to a value larger than the default value of 1500.

Use the ifconfig command to increase the MTU size. For example, enter the
following where <x> is the interface number:

   ifconfig eth<x> mtu 9000 up

This setting is not saved across reboots. The setting change can be made
permanent by adding 'MTU=9000' to the file:
/etc/sysconfig/network-scripts/ifcfg-eth<x> for RHEL or to the file
/etc/sysconfig/network/<config_file> for SLES.



NOTES:
- The maximum MTU setting for Jumbo Frames is 9216. This value coincides
  with the maximum Jumbo Frames size of 9234 bytes.
- Using Jumbo frames at 10 or 100 Mbps is not supported and may result in
  poor performance or loss of link.



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
http://ftp.kernel.org/pub/software/network/ethtool/


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Known Issues/Troubleshooting
----------------------------


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.


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


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:
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).


Do Not Use LRO When Routing Packets
-----------------------------------

Due to a known general compatibility issue with LRO and routing, do not use LRO
when routing packets.


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


MSI-X Issues with Kernels Between 2.6.19 - 2.6.21 (inclusive)
-------------------------------------------------------------

Kernel panics and instability may be observed on any MSI-X hardware if you use
irqbalance with kernels between 2.6.19 and 2.6.21. If such problems are
encountered, you may disable the irqbalance daemon or upgrade to a newer
kernel.


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.

Under Redhat 5.4-GA, System May Crash when Closing Guest OS Window after
Loading/Unloading Physical Function (PF) Driver

Do not remove the igb driver from Dom0 while Virtual Functions (VFs) are
assigned to guests. VFs must first use the xm "pci-detach" command to hot-plug
the VF device out of the VM it is assigned to or else shut down the VM.

Unloading Physical Function (PF) Driver Causes System Reboots When VM is
Running and VF is Loaded on the VM.

Do not unload the PF driver (igb) while VFs are assigned to guests.


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.


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Support
-------
For general information, go to the Intel support website at:
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.



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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 - 2016 Intel Corporation.
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Trademarks
----------

Intel, Itanium, and Pentium are trademarks or registered trademarks of Intel
Corporation or its subsidiaries in the United States and other countries.

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