ice Linux* Base Driver for the Intel(R) Ethernet 800 Series
===============================================================================

June 23, 2023

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

Contents
--------

- Overview
- Identifying Your Adapter
- Important Notes
- Building and Installation
- Command Line Parameters
- Additional Features & Configurations
- Performance Optimization
- Known Issues/Troubleshooting


Overview
========
This driver supports kernel versions 3.10.0 and newer. However, some features
may require a newer kernel version. The associated Virtual Function (VF) driver
for this driver is iavf. The associated RDMA driver for this driver is irdma.

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

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.

This driver supports XDP (Express Data Path) on kernel 4.14 and later and
AF_XDP zero-copy on kernel 4.18 and later. Note that XDP is blocked for frame
sizes larger than 3KB.


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
========================
The driver is compatible with devices based on the following:
  * Intel(R) Ethernet Controller E810-C
  * Intel(R) Ethernet Controller E810-XXV
  * Intel(R) Ethernet Connection E822-C
  * Intel(R) Ethernet Connection E822-L
  * Intel(R) Ethernet Connection E823-C
  * Intel(R) Ethernet Connection E823-L

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


Important Notes
===============

Configuring SR-IOV for improved network security
------------------------------------------------
In a virtualized environment, on Intel(R) Ethernet Network Adapters that
support SR-IOV or Intel(R) Scalable I/O Virtualization (Intel(R) Scalable IOV),
the virtual function (VF) may be subject to malicious behavior.
Software-generated layer two frames, like IEEE 802.3x (link flow control), IEEE
802.1Qbb (priority based flow-control), and others of this type, are not
expected and can throttle traffic between the host and the virtual switch,
reducing performance. To resolve this issue, and to ensure isolation from
unintended traffic streams, configure all SR-IOV or Intel Scalable IOV enabled
ports for VLAN tagging from the administrative interface on the PF. This
configuration allows unexpected, and potentially malicious, frames to be
dropped.

See "Configuring VLAN Tagging on SR-IOV Enabled Adapter Ports" or "Intel(R)
Scalable I/O Virtualization Support" later in this README for configuration
instructions.


Do not unload port driver if VF with active VM is bound to it
-------------------------------------------------------------
Do not unload a port's driver if a Virtual Function (VF) with an active Virtual
Machine (VM) is bound to it. Doing so will cause the port to appear to hang.
Once the VM shuts down, or otherwise releases the VF, the command will complete.


Firmware Recovery Mode
----------------------
A device will enter Firmware Recovery mode if it detects a problem that
requires the firmware to be reprogrammed. When a device is in Firmware Recovery
mode it will not pass traffic or allow any configuration; you can only attempt
to recover the device's firmware. Refer to the Intel(R) Ethernet Adapters and
Devices User Guide for details on Firmware Recovery Mode and how to recover
from it.


Important notes for SR-IOV, RDMA, and Link Aggregation
------------------------------------------------------
The VF driver will not block teaming/bonding/link aggregation, but this is not
a supported feature. Do not expect failover or load balancing on the VF
interface.

LAG and RDMA are compatible only in certain conditions. See the "RDMA (Remote
Direct Memory Access)" section later in this README for more information.

Bridging and MACVLAN are also affected by this. If you wish to use bridging or
MACVLAN with RDMA/SR-IOV, you must set up bridging or MACVLAN before enabling
RDMA or SR-IOV. If you are using bridging or MACVLAN in conjunction with SR-IOV
and/or RDMA, and you want to remove the interface from the bridge or MACVLAN,
you must follow these steps:
1. Remove RDMA if it is active
2. Destroy SR-IOV VFs if they exist
3. Remove the interface from the bridge or MACVLAN
4. Reactivate RDMA and recreate SR-IOV VFs as needed


Building and Installation
=========================
The ice driver requires the Dynamic Device Personalization (DDP) package file
to enable advanced features (such as dynamic tunneling, Intel(R) Ethernet Flow
Director, RSS, and ADQ, or others). The driver installation process installs
the default DDP package file and creates a soft link ice.pkg to the physical
package ice-x.x.x.x.pkg in the firmware root directory (typically
/lib/firmware/ or /lib/firmware/updates/). The driver install process also puts
both the driver module and the DDP file in the initramfs/initrd image.

NOTE: When the driver loads, it looks for intel/ice/ddp/ice.pkg in the firmware
root. If this file exists, the driver will download it into the device. If not,
the driver will go into Safe Mode where it will use the configuration contained
in the device's NVM. This is NOT a supported configuration and many advanced
features will not be functional. See "Dynamic Device Personalization" later for
more information.


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

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

   # tar zxf ice-<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 ice-<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/ice/ice.ko

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

   NOTE: To build the driver using the schema for unified ethtool statistics
   defined in https://sourceforge.net/p/e1000/wiki/Home/, use the following
   command:

   # make CFLAGS_EXTRA='-DUNIFIED_STATS' install

   NOTE: To compile the driver with ADQ (Application Device Queues) flags set,
   use the following command, where <nproc> is the number of logical cores:

   # make -j<nproc> CFLAGS_EXTRA='-DADQ_PERF_COUNTERS' install

   (This will also apply the above 'make install' command.)

   NOTE: You may see warnings from depmod related to unknown RDMA symbols
   during the make of the OOT base driver. These warnings are normal and
   appear because the in-tree RDMA driver will not work with the OOT base
   driver. To address the issue, you need to install the latest OOT versions
   of the base and RDMA drivers.


5. Load the module using the modprobe command.

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

   # modinfo ice
   # modprobe ice

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

   # rmmod ice; modprobe ice

NOTE: To enable verbose debug messages in the kernel log, use the dynamic debug
feature (dyndbg). See "Dynamic Debug" later in this README for more information.

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>

 
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 ice-<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>

3. If your distribution or kernel does not contain inbox support for auxiliary
   bus, you must also install the auxiliary RPM:

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

NOTE: On some distributions, the auxiliary RPM may fail to install due to
missing kernel-devel headers. To workaround this issue, specify '--excludepath'
during installation. For example:

# rpm -Uvh auxiliary-1.0.0-1.x86_64.rpm
--excludepath=/lib/modules/3.10.0-957.el7.x86_64/source/include/linux/auxiliary_
bus.h

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
=======================
The only command line parameter the ice driver supports is the debug parameter
that can control the default logging verbosity of the driver. (Note: dyndbg
also provides dynamic debug information.)

In general, use ethtool and other OS-specific commands to configure
user-changeable parameters after the driver is loaded.


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

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/


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.


Dynamic Device Personalization
------------------------------
Dynamic Device Personalization (DDP) allows you to change the packet processing
pipeline of a device by applying a profile package to the device at runtime.
Profiles can be used to, for example, add support for new protocols, change
existing protocols, or change default settings. DDP profiles can also be rolled
back without rebooting the system.

The ice driver automatically installs the default DDP package file during
driver installation. NOTE: It's important to do 'make install' during initial
ice driver installation so that the driver loads the DDP package automatically.

The DDP package loads during device initialization. The driver looks for
intel/ice/ddp/ice.pkg in your firmware root (typically /lib/firmware/ or
/lib/firmware/updates/) and checks that it contains a valid DDP package file.

If the driver is unable to load the DDP package, the device will enter Safe
Mode. Safe Mode disables advanced and performance features and supports only
basic traffic and minimal functionality, such as updating the NVM or
downloading a new driver or DDP package. Safe Mode only applies to the affected
physical function and does not impact any other PFs. See the "Intel(R) Ethernet
Adapters and Devices User Guide" for more details on DDP and Safe Mode.

NOTES:
- If you encounter issues with the DDP package file, you may need to download
an updated driver or DDP package file. See the log messages for more
information.

- The ice.pkg file is a symbolic link to the default DDP package file installed
by the Linux-firmware software package or the ice out-of-tree driver
installation.

- You cannot update the DDP package if any PF drivers are already loaded. To
overwrite a package, unload all PFs and then reload the driver with the new
package.

- Only the first loaded PF per device can download a package for that device.

You can install specific DDP package files for different physical devices in
the same system. To install a specific DDP package file:

1. Download the DDP package file you want for your device.

2. Rename the file ice-xxxxxxxxxxxxxxxx.pkg, where 'xxxxxxxxxxxxxxxx' is the
unique 64-bit PCI Express device serial number (in hex) of the device you want
the package downloaded on. The filename must include the complete serial number
(including leading zeros) and be all lowercase. For example, if the 64-bit
serial number is b887a3ffffca0568, then the file name would be
ice-b887a3ffffca0568.pkg.

To find the serial number from the PCI bus address, you can use the following
command:

# lspci -vv -s af:00.0 | grep -i Serial
Capabilities: [150 v1] Device Serial Number b8-87-a3-ff-ff-ca-05-68

You can use the following command to format the serial number without the
dashes:

# lspci -vv -s af:00.0 | grep -i Serial | awk '{print $7}' | sed s/-//g
b887a3ffffca0568

3. Copy the renamed DDP package file to /lib/firmware/updates/intel/ice/ddp/.
If the directory does not yet exist, create it before copying the file.

4. Unload all of the PFs on the device.

5. Reload the driver with the new package.

NOTE: The presence of a device-specific DDP package file overrides the loading
of the default DDP package file (ice.pkg).


RDMA (Remote Direct Memory Access)
----------------------------------
Remote Direct Memory Access, or RDMA, allows a network device to transfer data
directly to and from application memory on another system, increasing
throughput and lowering latency in certain networking environments.

The ice driver supports the following RDMA protocols:
- iWARP (Internet Wide Area RDMA Protocol)
- RoCEv2 (RDMA over Converged Ethernet)
The major difference is that iWARP performs RDMA over TCP, while RoCEv2 uses
UDP.

RDMA requires auxiliary bus support. Refer to "Auxiliary Bus" in this
README for more information.

Devices based on the Intel(R) Ethernet 800 Series do not support RDMA when
operating in multiport mode with more than 4 ports.

For detailed installation and configuration information for RDMA, see the
README file in the irdma driver tarball.


RDMA in the VF
--------------
Devices based on the Intel(R) Ethernet 800 Series support RDMA in a Linux VF,
on supported Windows or Linux hosts.

The iavf driver supports the following RDMA protocols in the VF:
- iWARP (Internet Wide Area RDMA Protocol)
- RoCEv2 (RDMA over Converged Ethernet)

Refer to the README inside the irdma driver tarball for details on configuring
RDMA in the VF.

NOTE: To support VF RDMA, load the irdma driver on the host before creating
VFs. Otherwise VF RDMA support may not be negotiated between the VF and PF
driver.


Auxiliary Bus
-------------
Inter-Driver Communication (IDC) is the mechanism in which LAN drivers (such as
ice) communicate with peer drivers (such as irdma). Starting in kernel 5.11,
Intel LAN and RDMA drivers use an auxiliary bus mechanism for IDC.

RDMA functionality requires use of the auxiliary bus.

If your kernel supports the auxiliary bus, the LAN and RDMA drivers will use
the inbox auxiliary bus for IDC. For kernels lower than 5.11, the base driver
will automatically install an out-of-tree auxiliary bus module.


NVM Express* (NVMe) over TCP and Fabrics
----------------------------------------
RDMA provides a high throughput, low latency means to directly access NVM
Express* (NVMe*) drives on a remote server.

Refer to the following for details on supported operating systems and how to
set up and configure your server and client systems:
- NVM Express over TCP for Intel(R) Ethernet Products Configuration Guide
- NVM Express over Fabrics for Intel(R) Ethernet Products with RDMA
Configuration Guide

Both guides are available on the Intel Technical Library at:
https://www.intel.com/content/www/us/en/design/products-and-solutions/networking
-and-io/ethernet-controller-e810/technical-library.html


Link Aggregation and RDMA
-------------------------
Link aggregation (LAG) and RDMA are compatible only if all the following are
true:
- You are using an Intel Ethernet 810 Series device with the latest drivers and
NVM installed.
- RDMA technology is set to RoCEv2.
- LAG configuration is active-backup.
- Bonding is between two ports within the same device.
- The QoS configuration of the two ports matches prior to the bonding of the
devices.

If the above conditions are not met:
- The PF driver will not enable RDMA.
- RDMA peers will not be able to register with the PF.

NOTE: The first interface added to an aggregate (bond) is assigned as the
"primary" interface for RDMA and LAG functionality. If LAN interfaces are
assigned to the bond and you remove the primary interface from the bond, RDMA
will not function properly over the bonded interface. To address the issue,
remove all interfaces from the bond and add them again. Interfaces that are not
assigned to the bond will operate normally.


Application Device Queues (ADQ)
-------------------------------
Application Device Queues (ADQ) allow you to dedicate one or more queues to a
specific application. This can reduce latency for the specified application,
and allow Tx traffic to be rate limited per application.

The ADQ information contained here is specific to the ice driver. For more
details, refer to the E810 ADQ Configuration Guide at:
https://cdrdv2.intel.com/v1/dl/getContent/609008

Requirements:
- Kernel version: Varies by feature. Refer to the E810 ADQ Configuration Guide
for more information on required kernel versions for different ADQ features.
- Operating system: Red Hat* Enterprise Linux* 7.5+ or SUSE* Linux Enterprise
Server* 12+
- The latest ice driver and NVM image (Note: You must compile the ice driver
with the ADQ flag as shown in the "Building and Installation" section.)
- The sch_mqprio, act_mirred and cls_flower modules must be loaded. For example:
# modprobe sch_mqprio
# modprobe act_mirred
# modprobe cls_flower
- The latest version of iproute2
We recommend the following installation method:
# cd iproute2
# ./configure
# make DESTDIR=/opt/iproute2 install
# ln -s /opt/iproute2/sbin/tc /usr/local/sbin/tc

When ADQ is enabled:
- You cannot change RSS parameters, the number of queues, or the MAC address in
the PF or VF. Delete the ADQ configuration before changing these settings.
- The driver supports subnet masks for IP addresses in the PF and VF. When you
add a subnet mask filter, the driver forwards packets to the ADQ VSI instead of
the main VSI.
- When the PF adds or deletes a port VLAN filter for the VF, it will extend to
all the VSIs within that VF.
- The driver supports ADQ and GTP filters in the PF. Note: You must have a DDP
package that supports GTP; the default OS package does not. Download the
appropriate package from your hardware vendor and load it on your device.
- ADQ allows tc ingress filters that include any destination MAC address.
- You can configure up to 256 queue pairs (256 MSI-X interrupts) per PF.

See "Creating traffic class filters" in this README for more information on
configuring filters, including examples. See the E810 ADQ Configuration Guide
for detailed instructions.

ADQ KNOWN ISSUES:
- The latest RHEL and SLES distros have kernels with back-ported support for
ADQ. For all other Linux distributions, you must use LTS Linux kernel v4.19.58
or higher to use ADQ. The latest out-of-tree driver is required for ADQ on all
operating systems.

- You must clear ADQ configuration in the reverse order of the initial
configuration steps. Issues may result if you do not execute the steps to clear
ADQ configuration in the correct order.

- ADQ configuration is not supported on a bonded or teamed ice interface.
Issuing the ethtool or tc commands to a bonded ice interface will result in
error messages from the ice driver to indicate the operation is not supported.

- If the application stalls, the application-specific queues may stall for up
to two seconds. Configuring only one application per Traffic Class (TC) channel
may resolve the issue.

- DCB and ADQ cannot coexist. A switch with DCB enabled might remove the ADQ
configuration from the device. To resolve the issue, do not enable DCB on the
switch ports being used for ADQ. You must disable LLDP on the interface and
stop the firmware LLDP agent using the following command:
   # ethtool --set-priv-flags <ethX> fw-lldp-agent off

- MACVLAN offloads and ADQ are mutually exclusive. System instability may occur
if you enable l2-fwd-offload and then set up ADQ, or if you set up ADQ and then
enable l2-fwd-offload.

- NOTE (unrelated to Intel drivers): The version 5.8.0 Linux kernel introduced
a bug that broke the interrupt affinity setting mechanism, which breaks the
ability to pin interrupts to ADQ hardware queues. Use an earlier or later
version of the Linux kernel.

- A core-level reset of an ADQ-configured PF port (rare events usually
triggered by other failures in the device or ice driver) results in loss of ADQ
configuration. To recover, reapply the ADQ configuration to the PF interface.

-  Commands such as 'tc qdisc add' and 'ethtool -L' will cause the driver to
close the associated RDMA interface and reopen it. This will disrupt RDMA
traffic for 3-5 seconds until the RDMA interface is available again for
traffic.

-  Commands such as 'tc qdisc add' and 'ethtool -L' will clear other tuning
settings such as interrupt affinity. These tuning settings will need to be
reapplied. When the number of queues are increased using 'ethtool -L', the new
queues will have the same interrupt moderation settings as queue 0 (i.e., Tx
queue 0 for new Tx queues and Rx queue 0 for new Rx queues). You can change
this using the ethtool per-queue coalesce commands.

- TC filters may not get offloaded in hardware if you apply them immediately
after issuing the 'tc qdisc add' command. We recommend you wait 5 seconds after
issuing 'tc qdisc add' before adding TC filters. Dmesg will report the error if
TC filters fail to add properly.


Setting up ADQ
--------------
To set up the adapter for ADQ, where <ethX> is the interface in use:
1. Reload the ice driver to remove any previous TC configuration:

   # rmmod ice
   # modprobe ice

2. Enable hardware TC offload on the interface:

   # ethtool -K <ethX> hw-tc-offload on

3. Disable LLDP on the interface, if it isn't already:

   # ethtool --set-priv-flags <ethX> fw-lldp-agent off

4. Verify settings:

   # ethtool -k <ethX> | grep "hw-tc"
   # ethtool --show-priv-flags <ethX>


ADQ Configuration Script
------------------------
Intel also provides a script to configure ADQ. This script allows you configure
ADQ-specific parameters such as traffic classes, priority, filters, and ethtool
parameters.

Refer to the README.md file in scripts/adqsetup inside the driver tarball for
more information.

The script and README are also available as part of the Python Package Index:
https://pypi.org/project/adqsetup


Using ADQ with independent pollers
----------------------------------
The ice driver supports ADQ acceleration using independent pollers. Independent
pollers are kernel threads invoked by interrupts and are used for busy polling
on behalf of the application.

You can configure the number of queues per poller and poller timeout per ADQ
traffic class (TC) or queue group using the 'devlink dev param' interface.

To set the number of queue pairs per poller, use the following:

# devlink dev param set <pci/D:b:d.f> name tc<x>_qps_per_poller value <num>
cmode runtime

Where:
- <pci/D:b:d.f> is the PCI address of the device
(pci/Domain:bus:device.function).
- tc<x> is the traffic class number.
- <num> is the number of queues of the corresponding traffic class that each
poller would poll.

To set the timeout for the independent poller, use the following:

# devlink dev param set <pci/D:b:d.f> name tc<x>_poller_timeout value <num>
cmode runtime

Where:
- <pci/D:b:d.f> is the PCI address of the device
(pci/Domain:bus:device.function).
- tc<x> is the traffic class number.
- <num> is a nonzero integer value in jiffies.

For example:

- To configure 3 queues of TC1 to be polled by each independent poller:

# devlink dev param set pci/0000:3b:00.0 name tc1_qps_per_poller value 3 cmode
runtime

- To set the timeout value in jiffies for TC1 when no traffic is flowing:

# devlink dev param set pci/0000:3b:00.0 name tc1_poller_timeout value 1000
cmode runtime


Configuring ADQ flows per traffic class
---------------------------------------
The ice OOT driver allows you to configure inline Intel(R) Ethernet Flow
Director (Intel(R) Ethernet FD) filters per traffic class (TC) using the
devlink interface. Inline Intel Ethernet FD allows uniform distribution of
flows among queues in a TC.

NOTE:
- This functionality requires Linux kernel version 5.6 or newer and is
supported only with the OOT ice driver.
- You must enable Transmit Packet Steering (XPS) using receive queues for this
feature to work correctly.
- Per-TC filters set with devlink are not compatible with Intel Ethernet FD
filters set via ethtool.

Use the following to configure inline Intel Ethernet FD filters per TC:

# devlink dev param set <pci/D:b:d.f> name tc<x>_inline_fd value <setting>
cmode runtime

Where:
- <pci/D:b:d.f> is the PCI address of the device
(pci/Domain:bus:device.function).
- tc<x> is the traffic class number.
- <setting> is true to enable inline per-TC Intel Ethernet FD, or false to
disable it.

For example, to enable inline Intel Ethernet FD for TC1:

# devlink dev param set pci/0000:af:00.0 name tc1_inline_fd value true cmode
runtime

To show the current inline Intel Ethernet FD setting:

# devlink dev param show <pci/D:b:d.f> name tc<x>_inline_fd

For example, to show the inline Intel Ethernet FD setting for TC2 for the
specified device:

# devlink dev param show pci/0000:af:00.0 name tc2_inline_fd


Creating traffic classes
------------------------
NOTE: These instructions are not specific to ADQ configuration. Refer to the tc
and tc-flower man pages for more information on creating traffic classes (TCs).

To create traffic classes on the interface:

1. Use the tc command to create traffic classes. You can create a maximum of
   16 TCs per interface.

   # tc qdisc add dev <ethX> root mqprio num_tc <tcs> map <priorities>
     queues <count1@offset1 ...> hw 1 mode channel shaper bw_rlimit
     min_rate <min_rate1 ...> max_rate <max_rate1 ...>
   Where:
      num_tc <tcs>: The number of TCs to use.
      map <priorities>: The map of priorities to TCs. You can map up to
          16 priorities to TCs.
      queues <count1@offset1 ...>: For each TC, <num queues>@<offset>. The max
          total number of queues for all TCs is the number of cores.
      hw 1 mode channel: 'channel' with 'hw' set to 1 is a new hardware offload
          mode in mqprio that makes full use of the mqprio options, the TCs,
          the queue configurations, and the QoS parameters.
      shaper bw_rlimit: For each TC, sets the minimum and maximum bandwidth
          rates. The totals must be equal to or less than the port speed. This
          parameter is optional and is required only to set up the Tx rates.
      min_rate <min_rate1>: Sets the minimum bandwidth rate limit for each TC.
      max_rate <max_rate1 ...>: Sets the maximum bandwidth rate limit for each
          TC. You can set a min and max rate together.

NOTE:
- If you set max_rate to less than 50Mbps, then max_rate is rounded up to
50Mbps and a warning is logged in dmesg.
- See the mqprio man page and the examples below for more information.

2. Verify the bandwidth limit using network monitoring tools such as ifstat or
sar -n DEV [interval] [number of samples]

NOTE: Setting up channels via ethtool (ethtool -L) is not supported when the
TCs are configured using mqprio.

3. Enable hardware TC offload on the interface:

   # ethtool -K <ethX> hw-tc-offload on

4. Add clsact qdisc to enable adding ingress/egress filters for Rx/Tx:

   # tc qdisc add dev <ethX> clsact

5. Verify successful TC creation after qdisc is created:

   # tc qdisc show dev <ethX> ingress


TRAFFIC CLASS EXAMPLES:
See the tc and tc-flower man pages for more information on traffic control and
TC flower filters.

- To set up two TCs (tc0 and tc1), with 16 queues each, priorities 0-3 for
  tc0 and 4-7 for tc1, and max Tx rate set to 1Gbit for tc0 and 3Gbit for tc1:

  # tc qdisc add dev ens4f0 root mqprio num_tc 2 map 0 0 0 0 1 1 1 1 queues
    16@0 16@16 hw 1 mode channel shaper bw_rlimit max_rate 1Gbit 3Gbit
  Where:
      map 0 0 0 0 1 1 1 1: Sets priorities 0-3 to use tc0 and 4-7 to use tc1
      queues 16@0 16@16: Assigns 16 queues to tc0 at offset 0 and 16 queues
          to tc1 at offset 16

- To create 8 TCs with 256 queues spread across all the TCs, when ADQ is
enabled:

  # tc qdisc add dev <ethX> root mqprio num_tc 8 map 0 1 2 3 4 5 6 7
    queues 2@0 4@2 8@6 16@14 32@30 64@62 128@126 2@254 hw 1 mode channel

- To set a minimum rate for a TC:

  # tc qdisc add dev ens4f0 root mqprio num_tc 2 map 0 0 0 0 1 1 1 1 queues
    4@0 8@4 hw 1 mode channel shaper bw_rlimit min_rate 25Gbit 50Gbit

- To set a maximum data rate for a TC:

  # tc qdisc add dev ens4f0 root mqprio num_tc 2 map 0 0 0 0 1 1 1 1 queues
    4@0 8@4 hw 1 mode channel shaper bw_rlimit max_rate 25Gbit 50Gbit

- To set both minimum and maximum data rates together:

  # tc qdisc add dev ens4f0 root mqprio num_tc 2 map 0 0 0 0 1 1 1 1 queues
    4@0 8@4 hw 1 mode channel shaper bw_rlimit min_rate 10Gbit 20Gbit
    max_rate 25Gbit 50Gbit


Creating traffic class filters
------------------------------
NOTE: These instructions are not specific to ADQ configuration.

After creating traffic classes, use the tc command to create filters for
traffic. Refer to the tc and tc-flower man pages for more information.

To view all TC filters:

  # tc filter show dev <ethX> ingress
  # tc filter show dev <ethX> egress

For detailed configuration information and example code for switchdev mode on
Intel Ethernet 800 Series devices, refer to the configuration guide at
https://cdrdv2.intel.com/v1/dl/getContent/645272.

TC FILTER EXAMPLES:
To configure TCP TC filters, where:
      protocol: Encapsulation protocol (valid options are IP and 802.1Q).
      prio: Priority.
      flower: Flow-based traffic control filter.
      dst_ip: IP address of the device.
      ip_proto: IP protocol to use (TCP or UDP).
      dst_port: Destination port.
      src_port: Source port.
      skip_sw: Flag to add the rule only in hardware.
      hw_tc: Route incoming traffic flow to this hardware TC. The TC count
          starts at 0. For example, 'hw_tc 1' indicates that the filter
          is on the second TC.
      vlan_id: VLAN ID.

- TCP: Destination IP + L4 Destination Port
  To route incoming TCP traffic with a matching destination IP address and
  destination port to the given TC:

  # tc filter add dev <ethX> protocol ip ingress prio 1 flower dst_ip
    <ip_address> ip_proto tcp dst_port <port_number> skip_sw hw_tc 1

- TCP: Source IP + L4 Source Port
  To route outgoing TCP traffic with a matching source IP address and
  source port to the given TC associated with the given priority:

  # tc filter add dev <ethX> protocol ip egress prio 1 flower src_ip
    <ip_address> ip_proto tcp src_port <port_number> action skbedit priority 1


- TCP: Destination IP + L4 Destination Port + VLAN Protocol
  To route incoming TCP traffic with a matching destination IP address and
  destination port to the given TC using the VLAN protocol (802.1Q):

  # tc filter add dev <ethX> protocol 802.1Q ingress prio 1 flower
    dst_ip <ip address> eth_type ipv4 ip_proto tcp dst_port <port_number>
    vlan_id <vlan_id> skip_sw hw_tc 1


- To add a GTP filter:

  # tc filter add dev <ethX> protocol ip parent ffff: prio 1 flower
    src_ip 16.0.0.0/16 ip_proto udp dst_port 5678 enc_dst_port 2152
    enc_key_id <tunnel_id> skip_sw hw_tc 1

  Where:
    dst_port: inner destination port of application (5678)
    enc_dst_port: outer destination port (for GTP user data tunneling occurs
        on UDP port 2152)
    enc_key_id: tunnel ID (vxlan ID)


NOTE: You can add multiple filters to the device, using the same recipe (and
requires no additional recipe resources), either on the same interface or on
different interfaces. Each filter uses the same fields for matching, but can
have different match values.
  # tc filter add dev <ethX> protocol ip ingress prio 1 flower ip_proto
    tcp dst_port <port_number> skip_sw hw_tc 1
  # tc filter add dev <ethX> protocol ip egress prio 1 flower ip_proto tcp
    src_port <port_number> action skbedit priority 1

For example:

  # tc filter add dev ens4f0 protocol ip ingress prio 1 flower ip_proto
     tcp dst_port 5555 skip_sw hw_tc 1
  # tc filter add dev ens4f0 protocol ip egress prio 1 flower ip_proto
    tcp src_port 5555 action skbedit priority 1


Using TC filters to forward to a queue
--------------------------------------
The ice driver supports directing traffic based on L2/L3/L4 fields in the
packet to specific Rx queues, using the TC filter's class ID. Note: This
functionality can be used with or without ADQ.

To add filters for the desired queue, use the following tc command:

# tc filter add dev <ethX> ingress prio 1 protocol all flower src_mac
<mac_address> skip_sw classid ffff:<queue_id>

Where:
- <mac_address> is the MAC address(es) you want to direct to the Rx queue
- <queue_id> is the Rx queue ID number in hexadecimal

For example, to direct a single MAC address to queue 10:

# ethtool -K ens801 hw-tc-offload on
# tc qdisc add dev ens801 clsact
# tc filter add dev ens801 ingress prio 1 protocol all flower src_mac
68:dd:ac:dc:19:00 skip_sw classid ffff:b

To direct 4 source MAC addresses to Rx queues 10-13:

# ethtool -K ens801 hw-tc-offload on
# tc qdisc add dev ens801 clsact
# tc filter add dev ens801 ingress prio 1 protocol all flower src_mac
68:dd:ac:dc:19:00 skip_sw classid ffff:b
# tc filter add dev ens801 ingress prio 1 protocol all flower src_mac
68:dd:ac:dc:19:01 skip_sw classid ffff:c
# tc filter add dev ens801 ingress prio 1 protocol all flower src_mac
68:dd:ac:dc:19:02 skip_sw classid ffff:d
# tc filter add dev ens801 ingress prio 1 protocol all flower src_mac
68:dd:ac:dc:19:03 skip_sw classid ffff:e


Intel(R) Ethernet Flow Director
-------------------------------
The Intel(R) Ethernet Flow Director (Intel(R) Ethernet FD) performs the
following tasks:

- Directs receive packets according to their flows to different queues
- Enables tight control on routing a flow in the platform
- Matches flows and CPU cores for flow affinity

NOTE: An included script (set_irq_affinity) automates setting the IRQ to CPU
affinity.

NOTE: This driver supports the following flow types:
- IPv4
- TCPv4
- UDPv4
- SCTPv4
- IPv6
- TCPv6
- UDPv6
- SCTPv6
Each flow type supports valid combinations of IP addresses (source or
destination) and UDP/TCP/SCTP ports (source and destination). You can supply
only a source IP address, a source IP address and a destination port, or any
combination of one or more of these four parameters.

NOTE: This driver allows you to filter traffic based on a user-defined flexible
two-byte pattern and offset by using the ethtool user-def and mask fields. Only
L3 and L4 flow types are supported for user-defined flexible filters. For a
given flow type, you must clear all Intel Ethernet Flow Director filters before
changing the input set (for that flow type).

NOTE: Intel Ethernet Flow Director filters impact only LAN traffic. RDMA
filtering occurs before Intel Ethernet Flow Director, so Intel Ethernet Flow
Director filters will not impact RDMA.

The following table summarizes supported Intel Ethernet Flow Director features
across Intel(R) Ethernet controllers.

---------------------------------------------------------------------------
Feature             500 Series      700 Series         800 Series
===========================================================================
VF FLOW DIRECTOR    Supported       Routing to VF      Not supported
                                    not supported
---------------------------------------------------------------------------
IP ADDRESS RANGE    Supported       Not supported      Field masking
FILTER
---------------------------------------------------------------------------
IPv6 SUPPORT        Supported       Supported          Supported
---------------------------------------------------------------------------
CONFIGURABLE        Configured      Configured         Configured
INPUT SET           per port        globally           per port
---------------------------------------------------------------------------
ATR                 Supported       Supported          Not supported
---------------------------------------------------------------------------
FLEX BYTE FILTER    Starts at       Starts at          Starts at
                    beginning       beginning of       beginning
                    of packet       payload            of packet
---------------------------------------------------------------------------
TUNNELED PACKETS    Filter matches  Filter matches     Filter matches
                    outer header    inner header       inner header
---------------------------------------------------------------------------


Intel Ethernet Flow Director Filters
------------------------------------
Intel Ethernet Flow Director filters are used to direct traffic that matches
specified characteristics. They are enabled through ethtool's ntuple interface.
To enable or disable the Intel Ethernet Flow Director and these filters:

# ethtool -K <ethX> ntuple <off|on>

NOTE: When you disable ntuple filters, all the user programmed filters are
flushed from the driver cache and hardware. All needed filters must be re-added
when ntuple is re-enabled.

To display all of the active filters:

# ethtool -u <ethX>

To add a new filter:

# ethtool -U <ethX> flow-type <type> src-ip <ip> [m <ip_mask>] dst-ip <ip> [m
<ip_mask>] src-port <port> [m <port_mask>] dst-port <port> [m <port_mask>]
action <queue>
  Where:
    <ethX> - the Ethernet device to program
    <type> - can be ip4, tcp4, udp4, sctp4, ip6, tcp6, udp6, sctp6
    <ip> - the IP address to match on
    <ip_mask> - the IPv4 address to mask on
              NOTE: These filters use inverted masks. An inverted mask with 0
              means exactly match while with 0xF means DON'T CARE. Please
              refer to the examples for more details about inverted masks.
    <port> - the port number to match on
    <port_mask> - the 16-bit integer for masking
              NOTE: These filters use inverted masks.
    <queue> - the queue to direct traffic toward (-1 discards the
              matched traffic)

To delete a filter:

# ethtool -U <ethX> delete <N>
  Where <N> is the filter ID displayed when printing all the active filters,
  and may also have been specified using "loc <N>" when adding the filter.

EXAMPLES:
To add a filter that directs packet to queue 2:

# ethtool -U <ethX> flow-type tcp4 src-ip 192.168.10.1 dst-ip \
192.168.10.2 src-port 2000 dst-port 2001 action 2 [loc 1]

To set a filter using only the source and destination IP address:

# ethtool -U <ethX> flow-type tcp4 src-ip 192.168.10.1 dst-ip \
192.168.10.2 action 2 [loc 1]

To set a filter based on a user-defined pattern and offset:

# ethtool -U <ethX> flow-type tcp4 src-ip 192.168.10.1 dst-ip \
192.168.10.2 user-def 0x4FFFF action 2 [loc 1]

  where the value of the user-def field contains the offset (4 bytes) and
  the pattern (0xffff).

To match TCP traffic sent from 192.168.0.1, port 5300, directed to 192.168.0.5,
port 80, and then send it to queue 7:

# ethtool -U enp130s0 flow-type tcp4 src-ip 192.168.0.1 dst-ip 192.168.0.5
src-port 5300 dst-port 80 action 7

To add a TCPv4 filter with a partial mask for a source IP subnet. Here the
matched src-ip is 192.*.*.* (inverted mask):

# ethtool -U <ethX> flow-type tcp4 src-ip 192.168.0.0 m 0.255.255.255 dst-ip
192.168.5.12 src-port 12600 dst-port 31 action 12

NOTES:
For each flow-type, the programmed filters must all have the same matching
input set. For example, issuing the following two commands is acceptable:

# ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.1 src-port 5300 action 7
# ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.5 src-port 55 action 10

Issuing the next two commands, however, is not acceptable, since the first
specifies src-ip and the second specifies dst-ip:

# ethtool -U enp130s0 flow-type ip4 src-ip 192.168.0.1 src-port 5300 action 7
# ethtool -U enp130s0 flow-type ip4 dst-ip 192.168.0.5 src-port 55 action 10

The second command will fail with an error. You may program multiple filters
with the same fields, using different values, but, on one device, you may not
program two tcp4 filters with different matching fields.

The ice driver does not support matching on a subportion of a field, thus
partial mask fields are not supported.


Flex Byte Intel Ethernet Flow Director Filters
----------------------------------------------
The driver also supports matching user-defined data within the packet payload.
This flexible data is specified using the "user-def" field of the ethtool
command in the following way:
+----------------------------+--------------------------+
| 31    28    24    20    16 | 15    12    8    4    0  |
+----------------------------+--------------------------+
| offset into packet payload | 2 bytes of flexible data |
+----------------------------+--------------------------+

For example,
  ... user-def 0x4FFFF ...

tells the filter to look 4 bytes into the payload and match that value against
0xFFFF. The offset is based on the beginning of the payload, and not the
beginning of the packet. Thus

  flow-type tcp4 ... user-def 0x8BEAF ...

would match TCP/IPv4 packets which have the value 0xBEAF 8 bytes into the
TCP/IPv4 payload.

Note that ICMP headers are parsed as 4 bytes of header and 4 bytes of payload.
Thus to match the first byte of the payload, you must actually add 4 bytes to
the offset. Also note that ip4 filters match both ICMP frames as well as raw
(unknown) ip4 frames, where the payload will be the L3 payload of the IP4 frame.

The maximum offset is 64. The hardware will only read up to 64 bytes of data
from the payload. The offset must be even because the flexible data is 2 bytes
long and must be aligned to byte 0 of the packet payload.

The user-defined flexible offset is also considered part of the input set and
cannot be programmed separately for multiple filters of the same type. However,
the flexible data is not part of the input set and multiple filters may use the
same offset but match against different data.


RSS Hash Flow
-------------
Allows you to set the hash bytes per flow type and any combination of one or
more options for Receive Side Scaling (RSS) hash byte configuration.

# ethtool -N <ethX> rx-flow-hash <type> <option>

Where <type> is:
  tcp4	signifying TCP over IPv4
  udp4	signifying UDP over IPv4
  tcp6	signifying TCP over IPv6
  udp6	signifying UDP over IPv6
And <option> is one or more of:
  s	Hash on the IP source address of the Rx packet.
  d	Hash on the IP destination address of the Rx packet.
  f	Hash on bytes 0 and 1 of the Layer 4 header of the Rx packet.
  n	Hash on bytes 2 and 3 of the Layer 4 header of the Rx packet.

For example, to hash on the source and destination IP address for TCP IPv4
traffic, use the following:

# ethtool -N <ethX> rx-flow-hash tcp4 sd

To hash on the source and destination ports for UDP IPv6 traffic, use the
following:

# ethtool -N <ethX> rx-flow-hash udp6 sdfn


Accelerated Receive Flow Steering (aRFS)
----------------------------------------
Devices based on the Intel(R) Ethernet 800 Series support Accelerated Receive
Flow Steering (aRFS) on the PF. aRFS is a load-balancing mechanism that allows
you to direct packets to the same CPU where an application is running or
consuming the packets in that flow.

NOTES:
- aRFS requires that ntuple filtering is enabled via ethtool.
- aRFS support is limited to the following packet types:
    - TCP over IPv4 and IPv6
    - UDP over IPv4 and IPv6
    - Nonfragmented packets
- aRFS only supports Intel Ethernet Flow Director filters, which consist of the
source/destination IP addresses and source/destination ports.
- aRFS and ethtool's ntuple interface both use the device's Intel Ethernet Flow
Director. aRFS and ntuple features can coexist, but you may encounter
unexpected results if there's a conflict between aRFS and ntuple requests. See
"Intel(R) Ethernet Flow Director" for additional information.
 
To set up aRFS:
1. Enable the Intel Ethernet Flow Director and ntuple filters using ethtool.

   # ethtool -K <ethX> ntuple on

2. Set up the number of entries in the global flow table. For example:

   # NUM_RPS_ENTRIES=16384
   # echo $NUM_RPS_ENTRIES > /proc/sys/net/core/rps_sock_flow_entries

3. Set up the number of entries in the per-queue flow table. For example:

   # NUM_RX_QUEUES=64
   # for file in /sys/class/net/$IFACE/queues/rx-*/rps_flow_cnt; do
   # echo $(($NUM_RPS_ENTRIES/$NUM_RX_QUEUES)) > $file;
   # done

4. Disable the IRQ balance daemon (this is only a temporary stop of the service
   until the next reboot).

   # systemctl stop irqbalance

5. Configure the interrupt affinity.

   # set_irq_affinity <ethX>


To disable aRFS using ethtool:

# ethtool -K <ethX> ntuple off

NOTE: This command will disable ntuple filters and clear any aRFS filters in
software and hardware.

Example Use Case:
1. Set the server application on the desired CPU (e.g., CPU 4).

   # taskset -c 4 netserver

2. Use netperf to route traffic from the client to CPU 4 on the server with
   aRFS configured. This example uses TCP over IPv4.

   # netperf -H <Host IPv4 Address> -t TCP_STREAM


Enabling Virtual Functions (VFs) for SR-IOV
-------------------------------------------
Use sysfs to enable virtual functions (VF).

For example, you can create 4 VFs as follows:

# echo 4 > /sys/class/net/<ethX>/device/sriov_numvfs

To disable VFs, write 0 to the same file:

# echo 0 > /sys/class/net/<ethX>/device/sriov_numvfs

The maximum number of VFs for the ice driver is 256 total (all ports). To check
how many VFs each PF supports, use the following command:

# cat /sys/class/net/<ethX>/device/sriov_totalvfs
The VF driver will not block teaming/bonding/link aggregation, but this is not
a supported feature. Do not expect failover or load balancing on the VF
interface.


SR-IOV Live Migration
---------------------
You can use VFIO Device Migration to move an active virtual machine (VM)
between different physical machines so it does not lose its network connection.
After migrating, the virtual function (VF) will continue most Ethernet
operations without further interruption. During migration, data and VIRTCHNL
operations are sent to a buffer so the can br recreated when the migration
completes. If the memory allocated for the command buffer is exceeded, the
system will drop the buffer and disable the live migration capability for the
VF. You must reset the VF for live migration to be re-enabled.

NOTES:
- Live migration requires kernel version 5.15 to 5.17
- You cannot migrate a VM if it has a VF that is using RDMA.
- You can only migrate the VF to a device in the same family with a similar
firmware version. For example, you can migrate a VF from one 810 device to
another, but not from an 810 device to an 820 device.
- Any VF properties that are set by the PF will not be migrated. Make sure that
both devices have the same PF-set properties.

Refer to https://qemu.readthedocs.io/en/latest/devel/vfio-migration.html for
more details.


Intel(R) Scalable I/O Virtualization Support
--------------------------------------------
Intel(R) Scalable I/O Virtualization (Intel(R) Scalable IOV) allows you to
share a physical device across multiple virtual machines and applications.
Intel Scalable IOV provides your system the ability to share device resources
with different address domains using different abstractions. For example,
application processes may access a device using system calls and VMs may access
a device through virtual device interfaces.

For more information, please refer to the Intel Scalable I/O Virtualization
Technical Specification
<https://software.intel.com/sites/default/files/managed/cc/0e/intel-scalable-io-
virtualization-technical-specification.pdf> (login required)

The VF driver will not block teaming/bonding/link aggregation, but this is not
a supported feature. Do not expect failover or load balancing on the VF
interface.

Intel Scalable IOV is not available in the kernel driver. Download and install
the current ice driver to use this feature. Refer to the SUPPORT section for
where to download the current driver.

Requirements
------------

* Your system platform must support Intel Scalable IOV
* A network device based on an Intel(R) Ethernet 800 Series controller
* The host operating system must be a Linux distro using kernel version 5.12 -
5.15
* The host PF driver must be version 1.9.0, or later
* The guest operating system must be Linux
* The guest iAVF driver must be version 4.5.0, or later

Enabling Intel Scalable IOV
---------------------------

You can use Intel's Ethernet Port Configuration Tool (EPCT) to enable Intel
Scalable IOV. If the EPCT tool is not available, you can also enable Intel
Scalable IOV through your system's HII interface (if it has one). The
recommended method is to use the EPCT tool. To enable or disable Intel Scalable
IOV using the EPCT tool, use one of these commands:
#epct -nic=1 -set 'siov enable'
#epct -nic=1 -set 'siov disable'
Where -nic=1 specifies the Intel Ethernet device. See the EPCT tool
documentation for instructions on how to determine the NIC number of your
device.

If the EPCT tool is not available, and your system has an HII interface, you
can use the HII interface to enable/disable Intel Scalable IOV. Find the 'Intel
Scalable IOV (Scalable IOV)' setting and select your desired value.


Enabling Intel(R) Scalable I/O Virtualization Virtual Devices
-------------------------------------------------------------
Use the following steps to enable Intel(R) Scalable I/O Virtualization
(Intel(R) Scalable IOV) virtual devices (VDEVs):
Create an mdev
# echo "83b8f4f2-509f-382f-3c1e-e6bfe0fa1001" | sudo tee
/sys/class/mdev_bus/0000:38:00.0/mdev_supported_types/ice-ivdm/create
Use qemu to launch a VM with four processors
# sudo ./x86_64-softmmu/qemu-system-x86_64 \
	-enable-kvm \
	-m 1G \
	-smp 4 \
	-device
	vfio-pci,sysfsdev=/sys/bus/mdev/devices/83b8f4f2-509f-382f-3c1e-e6bfe0fa
1001 \
	-drive file=../../img/test.qcow2 \
	-nic user,hostfwd=tcp::5555-:22 \
	-monitor stdio


Displaying VF Statistics on the PF
----------------------------------
Use the following command to display the statistics for the PF and its VFs:

# ip -s link show dev <ethX>

NOTE: The output of this command can be very large due to the maximum number of
possible VFs.

The PF driver will display a subset of the statistics for the PF and for all
VFs that are configured. The PF will always print a statistics block for each
of the possible VFs, and it will show zero for all unconfigured VFs.


Configuring VLAN Tagging on SR-IOV Enabled Adapter Ports
--------------------------------------------------------
To configure VLAN tagging for the ports on an SR-IOV enabled adapter, use the
following command. The VLAN configuration should be done before the VF driver
is loaded or the VM is booted. The VF is not aware of the VLAN tag being
inserted on transmit and removed on received frames (sometimes called "port
VLAN" mode).

# ip link set dev <ethX> vf <id> vlan <vlan id>

For example, the following will configure PF eth0 and the first VF on VLAN 10:

# ip link set dev eth0 vf 0 vlan 10


Enabling a VF link if the port is disconnected
----------------------------------------------
If the physical function (PF) link is down, you can force link up (from the
host PF) on any virtual functions (VF) bound to the PF. Note that this requires
kernel support (Red Hat kernel 3.10.0-327 or newer, upstream kernel 3.11.0 or
newer) and associated iproute2 user space support.

For example, to force link up on VF 0 bound to PF eth0:

# ip link set eth0 vf 0 state enable

Note: If the command does not work, it may not be supported by your system.


Setting the MAC Address for a VF
--------------------------------
To change the MAC address for the specified VF:

# ip link set <ethX> vf 0 mac <address>

For example:

# ip link set <ethX> vf 0 mac 00:01:02:03:04:05

This setting lasts until the PF is reloaded.

NOTE: For untrusted VFs, assigning a MAC address for a VF from the host will
disable any subsequent requests to change the MAC address from within the VM.
This is a security feature. The VM is not aware of this restriction, so if this
is attempted in the VM, it will trigger MDD events. Trusted VFs are allowed to
change the MAC address from within the VM.


Trusted VFs and VF Promiscuous Mode
-----------------------------------
This feature allows you to designate a particular VF as trusted and allows that
trusted VF to request selective promiscuous mode on the Physical Function (PF).

To set a VF as trusted or untrusted, enter the following command in the
Hypervisor:

# ip link set dev <ethX> vf 1 trust [on|off]

NOTE: It's important to set the VF to trusted before setting promiscuous mode.
If the VM is not trusted, the PF will ignore promiscuous mode requests from the
VF. If the VM becomes trusted after the VF driver is loaded, you must make a
new request to set the VF to promiscuous.

Once the VF is designated as trusted, use the following commands in the VM to
set the VF to promiscuous mode. For promiscuous all:

# ip link set <ethX> promisc on
    Where <ethX> is a VF interface in the VM

For promiscuous Multicast:

# ip link set <ethX> allmulticast on
    Where <ethX> is a VF interface in the VM

NOTE: By default, the ethtool private flag vf-true-promisc-support is set to
"off," meaning that promiscuous mode for the VF will be limited. To set the
promiscuous mode for the VF to true promiscuous and allow the VF to see all
ingress traffic, use the following command:

# ethtool --set-priv-flags <ethX> vf-true-promisc-support on

The vf-true-promisc-support private flag does not enable promiscuous mode;
rather, it designates which type of promiscuous mode (limited or true) you will
get when you enable promiscuous mode using the 'ip link' commands above. You
can toggle the vf-true-promisc-support flag separately for all PFs.

Next, add a VLAN interface on the VF interface. For example:

# ip link add link eth2 name eth2.100 type vlan id 100

Note that the order in which you set the VF to promiscuous mode and add the
VLAN interface does not matter (you can do either first). The result in this
example is that the VF will get all traffic that is tagged with VLAN 100.


Virtual Function (VF) Tx Rate Limit
-----------------------------------
Use the ip command to configure the maximum or minimum Tx rate limit for a VF
from the PF interface.

For example, to set a maximum Tx rate limit of 8000Mbps for VF 0:

# ip link set eth0 vf 0 max_tx_rate 8000

For example, to set a minimum Tx rate limit of 1000Mbps for VF 0:

# ip link set eth0 vf 0 min_tx_rate 1000

NOTE:
- If DCB or ADQ are enabled on a PF, you cannot set a minimum Tx rate on the
VFs associated with that PF.
- If both DCB and ADQ are disabled on a PF, then you can set a minimum Tx rate
on the VFs associated with that PF.
- If you set a minimum Tx rate limit on a PF for SR-IOV VFs and then apply a
DCB or ADQ configuration, the PF cannot guarantee the minimum Tx rate limits
for those VFs.
- If you set a minimum Tx rate on VFs across multiple ports that have an
aggregate bandwidth over 100Gbps, the PFs cannot guarantee the minimum Tx rate
set for the VFs.


Malicious Driver Detection (MDD) for VFs
----------------------------------------
Some Intel Ethernet devices use Malicious Driver Detection (MDD) to detect
malicious traffic from the VF and disable Tx/Rx queues or drop the offending
packet until a VF driver reset occurs. You can view MDD messages in the PF's
system log using the dmesg command.

- If the PF driver logs MDD events from the VF, confirm that the correct VF
driver is installed.
- To restore functionality, you can manually reload the VF or VM or enable
automatic VF resets.
- When automatic VF resets are enabled, the PF driver will immediately reset
the VF and reenable queues when it detects MDD events on the receive path.
- If automatic VF resets are disabled, the PF will not automatically reset the
VF when it detects MDD events.

To enable or disable automatic VF resets, use the following command:

# ethtool --set-priv-flags <ethX> mdd-auto-reset-vf on|off


MAC and VLAN Anti-Spoofing Feature for VFs
------------------------------------------
When a malicious driver on a Virtual Function (VF) interface attempts to send a
spoofed packet, it is dropped by the hardware and not transmitted.

NOTE: This feature can be disabled for a specific VF:

# ip link set <ethX> vf <vf id> spoofchk {off|on}


VLAN Pruning
------------
The ice driver allows you to enable or disable VLAN pruning for the VF VSI
using the ethtool private flag vf-vlan-pruning.

NOTE:
- You cannot change this private flag while any VFs are active.
- If a port VLAN is configured, VLAN pruning will always be enabled.
- When VLAN pruning is enabled, the interface will:
    - Discard all packets with a VLAN tag when Rx VLAN filtering is disabled.
    - Discard untagged packets when Rx VLAN filtering is enabled.

To disable or enable VLAN pruning on all VFs, do the following:
1. Deinitialize any VFs.
2. On the PF, use the following command:

# ethtool --set-priv-flags <ethX> vf-vlan-pruning on|off
  Where:
  on - enables VLAN pruning
  off - disables VLAN pruning (default)

3. Initialize and configure any VFs.

VLAN pruning will then be disabled or enabled on any of these VFs, depending on
the flag you set.


Switchdev mode
--------------
The PF driver supports legacy and switchdev eSwitch modes. Switchdev mode
allows the driver to create additional port representor netdevs that enable a
control plane running on the host to configure filters for the VFs and also
handle default/exception traffic from the uplink and the VFs.

The driver loads in legacy mode by default. You can configure eSwitch modes
independently per physical port using the devlink command. You can change
between eSwitch modes only if no VFs have been created. If SR-IOV is enabled
and VFs are bound to the PF, you must do the following before changing between
switchdev and legacy mode:
- Unload all VFs that were bound
- Set the number of VFs on the PF to zero

NOTE:
- ADQ, trusted VFs, L2 forwarding, and S-IOV are not supported in switchdev
mode.
- Switchdev mode is not persistent across reboots or driver reloads.

To configure the device in switchdev mode, enter the following, where
<pci/0000:##:##.#> is the PCI address of the PF:

# devlink dev eswitch set <pci/0000:##:##.#> mode switchdev

For example:
# devlink dev eswitch set pci/0000:17:00.0 mode switchdev

To configure the device in legacy mode:

# devlink dev eswitch set <pci/0000:##:##.#> mode legacy

To check the current eSwitch mode:

# devlink dev eswitch show <pci/0000:##:##.#>

The ice driver supports the following hardware offloads in switchdev mode:
- Supported filter conditions:
    L2: Source/Destination MAC addresses, VLAN ID
    L3: Source/Destination IP addresses (IPv4, IPv6), IP protocol (TCP, UDP),
        ToS (IPv4), Traffic Class (IPv6), TTL (IPv4)
    L4: Source and Destination port
    VXLAN/GRETAP/GENEVE: VNI/GRE Key, Outer Destination IP, Inner Source IP,
        Inner Destination IP, Inner Destination MAC, TCP/UDP Source port and
        Destination port
    GTP: TEID, PDU type, QFI, Outer Destination IP, Outer Source IP
- Supported filter actions: redirect, drop

NOTE: GTP support requires kernel 5.18 and iproute2 5.18 or newer. On older
kernel versions, the DCF method provides the same functionality.

For detailed configuration information and example code for switchdev mode on
Intel Ethernet 800 Series devices, refer to the configuration guide at
https://cdrdv2.intel.com/v1/dl/getContent/645272.

At a high level, do the following to offload TC filters to the hardware and
create switch rules in switchdev mode:
1. Verify that switchdev mode is enabled.
2. Enable hw-tc-offload on the VF port representor (VF_PR).
3. For tunnel interfaces: Use the ip link command to create the tunnel.
4. Use the tc-flower command to create the switch rule.
5. Verify the offloaded flow in hardware.

Switchdev mode supports the following ip link commands to configure the VF:
* mac
* vlan, vxlan, geneve, gre, nvgre, gtp, qos, proto
* max_tx_rate
* min_tx_rate
* spoofchk
* query_rss
* state
* node_guid
* port_guid
NOTE: 'trust' is not supported. 'rate' is supported but deprecated; use
'max_tx_rate' instead.

To limit the VF's interrupt rate for Rx and Tx in switchdev mode, use the
following command, where <vf_pr> is the designated VF port representor and <N>
is the desired cap for the interrupt rate:

# ethtool -C <vf_pr> rx-usecs-high <N>


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 ip command to increase the MTU size. For example, enter the following
where <ethX> is the interface number:

# ip link set mtu 9000 dev <ethX>
# ip link set up dev <ethX>

This setting is not saved across reboots.

Add 'MTU=9000' to the following file to make the setting change permanent:
  /etc/sysconfig/network-scripts/ifcfg-<ethX> for RHEL
      or
  /etc/sysconfig/network/<config_file> for SLES

NOTE: The maximum MTU setting for jumbo frames is 9702. This corresponds to the
maximum jumbo frame size of 9728 bytes.

NOTE: This driver will attempt to use multiple page sized buffers to receive
each jumbo packet. This should help to avoid buffer starvation issues when
allocating receive packets.

NOTE: Packet loss may have a greater impact on throughput when you use jumbo
frames. If you observe a drop in performance after enabling jumbo frames,
enabling flow control may mitigate the issue.


Speed and Duplex Configuration
------------------------------
You cannot set speed, duplex, or autonegotiation settings using ethtool.


To see the speed configurations your device supports, run the following:

# ethtool <ethX>

To have your device advertise supported speeds, use the following:

# ethtool -s <ethX> advertise N
  Where N is a bitmask of the desired speeds.

For example, to have your device advertise 10000baseSR Full, use:

# ethtool -s <ethX> advertise 0x80000000000

For more details, please refer to the ethtool man page.


Data Center Bridging (DCB)
--------------------------
NOTE: The kernel assumes that TC0 is available, and will disable Priority Flow
Control (PFC) on the device if TC0 is not available. To fix this, ensure TC0 is
enabled when setting up DCB on your switch.

DCB is a configuration Quality of Service implementation in hardware. It uses
the VLAN priority tag (802.1p) to filter traffic. That means that there are 8
different priorities that traffic can be filtered into. It also enables
priority flow control (802.1Qbb) which can limit or eliminate the number of
dropped packets during network stress. Bandwidth can be allocated to each of
these priorities, which is enforced at the hardware level (802.1Qaz).

DCB is normally configured on the network using the DCBX protocol (802.1Qaz), a
specialization of LLDP (802.1AB). The ice driver supports the following
mutually exclusive variants of DCBX support:
1) Firmware-based LLDP Agent
2) Software-based LLDP Agent

In firmware-based mode, firmware intercepts all LLDP traffic and handles DCBX
negotiation transparently for the user. In this mode, the adapter operates in
"willing" DCBX mode, receiving DCB settings from the link partner (typically a
switch). The local user can only query the negotiated DCB configuration. For
information on configuring DCBX parameters on a switch, please consult the
switch manufacturer's documentation.

In software-based mode, LLDP traffic is forwarded to the network stack and user
space, where a software agent can handle it. In this mode, the adapter can
operate in either "willing" or "nonwilling" DCBX mode and DCB configuration can
be both queried and set locally. This mode requires the FW-based LLDP Agent to
be disabled.

NOTE:
- You can enable and disable the firmware-based LLDP Agent using an ethtool
private flag. Refer to the "FW-LLDP (Firmware Link Layer Discovery Protocol)"
section in this README for more information.
- In software-based DCBX mode, you can configure DCB parameters using software
LLDP/DCBX agents that interface with the Linux kernel's DCB Netlink API. We
recommend using OpenLLDP as the DCBX agent when running in software mode. For
more information, see the OpenLLDP man pages and
https://github.com/intel/openlldp.
- The driver implements the DCB netlink interface layer to allow the user space
to communicate with the driver and query DCB configuration for the port.
- iSCSI with DCB is not supported.


L3 QoS mode
-----------
The ice driver supports setting DSCP-based Layer 3 Quality of Service (L3 QoS)
in the PF driver. The driver initializes in L2 QoS mode. L3 QoS mode is:
- Automatically enabled when the first DSCP/ToS to TC mapping is defined
- Automatically disabled when the last DSCP/ToS to TC mapping is removed

The following is an example of how to map a DSCP/ToS to a TC:

# lldptool -T -i <ethX> -V APP app=<prio>,<sel>,<pid>
  where:
    <prio>: The TC assigned to the DSCP/ToS code point
    <sel>: 5 for DSCP to TC mapping
    <pid>: The DSCP/ToS code point

For example, to map packets containing DSCP value 63 to traffic class 0 on
interface eth0:

# lldptool -T -i eth0 -V APP app=63,5,0

To remove a mapping, use the following:

# lldptool -T -I <ethX> -V APP -d app=<prio>,<sel>,<pid>

To view the currently configured mappings, use the following:

# lldptool -t -i <ethX> -V APP -c

NOTE:
- L3 QoS mode is not available when FW-LLDP is enabled. You also cannot enable
FW-LLDP if L3 QoS mode is active. Disable FW-LLDP before switching to L3 QoS
mode. Refer to the "FW-LLDP (Firmware Link Layer Discovery Protocol)" section
in this README for more information on disabling FW-LLDP.
- Once a mapping has been submitted for a DSCP value, another mapping for that
value will not be accepted until the first one has been deleted.


FW-LLDP (Firmware Link Layer Discovery Protocol)
------------------------------------------------
Use ethtool to change FW-LLDP settings. The FW-LLDP setting is per port and
persists across boots.

To enable LLDP:

# ethtool --set-priv-flags <ethX> fw-lldp-agent on

To disable LLDP:

# ethtool --set-priv-flags <ethX> fw-lldp-agent off

To check the current LLDP setting:

# ethtool --show-priv-flags <ethX>

NOTE: You must enable the UEFI HII "LLDP Agent" attribute for this setting to
take effect. If "LLDP AGENT" is set to disabled, you cannot enable it from the
OS.


Forward Error Correction (FEC)
------------------------------
Allows you to set the Forward Error Correction (FEC) mode. FEC improves link
stability, but increases latency. Many high quality optics, direct attach
cables, and backplane channels provide a stable link without FEC.

NOTE:
For devices to benefit from this feature, link partners must have FEC enabled.

If you enable the flag 'allow-no-fec-modules-in-auto', Auto FEC negotiation
will include 'No FEC' in case your link partner does not have FEC enabled or is
not FEC capable.
# ethtool --set-priv-flags <ethX> allow-no-fec-modules-in-auto on

NOTE:

On kernels older than 4.14, use the following private flags to disable
FEC modes:
  rs-fec (0 to disable, 1 to enable)
  base-r-fec (0 to disable, 1 to enable)
On kernel 4.14 or later, use ethtool to get/set the following FEC modes:
  No FEC
  Auto FEC
  BASE-R FEC
  RS-FEC


Link-Level Flow Control (LFC)
-----------------------------
Ethernet Flow Control (IEEE 802.3x) can be configured with ethtool to enable
receiving and transmitting pause frames for ice. When transmit is enabled,
pause frames are generated when the receive packet buffer crosses a predefined
threshold. When receive is enabled, the transmit unit will halt for the time
delay specified when a pause frame is received.

NOTE: You must have a flow control capable link partner.

Flow Control is disabled by default.

Use ethtool to change the flow control settings.

To enable or disable Rx or Tx Flow Control:

# ethtool -A <ethX> rx <on|off> tx <on|off>

Note: This command only enables or disables Flow Control if auto-negotiation is
disabled. If auto-negotiation is enabled, this command changes the parameters
used for auto-negotiation with the link partner.

Note: Flow Control auto-negotiation is part of link auto-negotiation. Depending
on your device, you may not be able to change the auto-negotiation setting.

NOTE:
- The ice driver requires flow control on both the port and link partner. If
flow control is disabled on one of the sides, the port may appear to hang on
heavy traffic.
- You may encounter issues with link-level flow control (LFC) after disabling
DCB. The LFC status may show as enabled but traffic is not paused. To resolve
this issue, disable and reenable LFC using ethtool:

 # ethtool -A <ethX> rx off tx off
 # ethtool -A <ethX> rx on tx on


Limiting the Maximum Bitrate for a Transmit Queue
-------------------------------------------------
The ice driver supports limiting the transmit queue bit rate with the
tx_maxrate sysfs entry. Use this entry to set a maximum bitrate in Mbps. A
value of zero means no limiting.
Setting the bit rate for transmit queue 1 to 300 Mbps:
# echo 300 > /sys/class/<ethx>/queues/tx-1/tx_maxrate
Removing the limit:
# echo 0 > /sys/class/<ethx>/queues/tx-1/tx_maxrate
NAPI
----
This driver supports NAPI (Rx polling mode). For more information on NAPI, see
https://docs.kernel.org/networking/napi.html.


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.

ice devices support L2 Forwarding Offload. This will offload the processing
required for L2 Forwarding from the system processors to the ice device.
Perform the following steps to enable L2 Forwarding Offload:

1. Enable L2 Forwarding offload:

   # ethtool -K <ethX> l2-fwd-offload on

2. Create the MACVLAN netdevs and bind them to the PF.

3. Bring up/enable the MACVLAN netdevs.

NOTE: MACVLAN offloads and ADQ are mutually exclusive. System instability may
occur if you enable l2-fwd-offload and then set up ADQ, or if you set up ADQ
and then enable l2-fwd-offload.


IEEE 802.1ad (QinQ) Support
---------------------------
The IEEE 802.1ad standard, informally known as QinQ, allows for multiple VLAN
IDs within a single Ethernet frame. VLAN IDs are sometimes referred to as
"tags," and multiple VLAN IDs are thus referred to as a "tag stack." Tag stacks
allow L2 tunneling and the ability to separate traffic within a particular VLAN
ID, among other uses.

The following are examples of how to configure 802.1ad (QinQ):

# ip link add link eth0 eth0.24 type vlan proto 802.1ad id 24
# ip link add link eth0.24 eth0.24.371 type vlan proto 802.1Q id 371
  Where "24" and "371" are example VLAN IDs.

NOTES:
- 802.1ad (QinQ) is supported in 3.19 and later kernels.
- VLAN protocols use the following EtherTypes:
    802.1Q = EtherType 0x8100
    802.1ad = EtherType 0x88A8
- For QinQ traffic to work at MTU 1500, the L2 peer (switch port or another
NIC) should be able to receive Ethernet frames of 1526 bytes. Some third-party
NICs support a maximum Ethernet frame size of 1522 bytes at MTU 1500, which
will cause QinQ traffic to fail. To work around this issue, restrict the MTU on
the Intel Ethernet device to 1496.


Double VLANs
------------
Devices based on the Intel(R) Ethernet 800 Series can process up to two VLANs
in a packet when all the following are installed:
- ice driver version 1.4.0 or later
- NVM version 2.4 or later
- ice DDP package version 1.3.21 or later
If you don't use the versions above, the only supported VLAN configuration is
single 802.1Q VLAN traffic.

When two VLAN tags are present in a packet, the outer VLAN tag can be either
802.1Q or 802.1ad. The inner VLAN tag must always be 802.1Q.

Note the following limitations:
- For each VF, the PF can only allow VLAN hardware offloads (insertion and
stripping) of one type, either 802.1Q or 802.1ad.
- You can't enable or disable outer or single 802.1Q or 802.1ad filtering
separately. They are either both on or both off.
- In SR-IOV mode, the VF may not receive all network traffic based on the inner
VLAN header when VF true promiscuous mode (vf-true-promisc-support) and double
VLANs are enabled.

To enable outer or single 802.1Q VLAN insertion and stripping and disable
802.1ad VLAN insertion and stripping:
# ethtool -K <ethX> rxvlan on txvlan on rx-vlan-stag-hw-parse off
tx-vlan-stag-hw-insert off

To enable outer or single 802.1ad VLAN insertion and stripping and disable
802.1Q VLAN insertion and stripping:
# ethtool -K <ethX> rxvlan off txvlan off rx-vlan-stag-hw-parse on
tx-vlan-stag-hw-insert on

To enable outer or single VLAN filtering:
# ethtool -K <ethX> rx-vlan-filter on rx-vlan-stag-filter on

To disable outer or single VLAN filtering:
# ethtool -K <ethX> rx-vlan-filter off rx-vlan-stag-filter off


Combining QinQ with SR-IOV VFs
------------------------------
We recommend you always configure a port VLAN for the VF from the PF. If a port
VLAN is not configured, the VF driver may only offload VLANs via software. The
PF allows all VLAN traffic to reach the VF, and the VF manages all VLAN traffic.

When the device is configured for double VLANs and the PF has configured a port
VLAN:
- The VF can only offload guest VLANs for 802.1Q traffic.
- The VF can only configure VLAN filtering rules for guest VLANs using 802.1Q
traffic.

However, when the device is configured for double VLANs and the PF has NOT
configured a port VLAN:
- You must use iavf driver version 4.1.0 or later to offload and filter VLANs.
- The PF turns on VLAN pruning and antispoof in the VF's VSI by default. The VF
will not transmit or receive any tagged traffic until the VF requests a VLAN
filter.
- The VF can offload (insert and strip) the outer VLAN tag of 802.1Q or 802.1ad
traffic.
- The VF can create filter rules for the outer VLAN tag of both 802.1Q and
802.1ad traffic.

If the PF does not support double VLANs, the VF can hardware offload single
802.1Q VLANs without a port VLAN.

When the PF is enabled for double VLANs, for iavf drivers before version 4.1.x:
- VLAN hardware offloads and filtering are supported only when the PF has
configured a port VLAN.
- VLAN filtering, insertion, and stripping will be software offloaded when no
port VLAN is configured.

To see VLAN filtering and offload capabilities, use the following command:

# ethtool -k <ethX> | grep vlan


IEEE 1588 Precision Time Protocol (PTP) Hardware Clock (PHC)
------------------------------------------------------------
Precision Time Protocol (PTP) is used to synchronize clocks in a computer
network. PTP support varies among Intel devices that support this driver. Use
'ethtool -T <ethX>' to get a definitive list of PTP capabilities supported by
the device.

A detailed user guide is available for the following devices. Refer to it for
advanced configuration of this feature.
- Intel(R) Ethernet Network Adapter E810-XXV-4T:
  https://cdrdv2.intel.com/v1/dl/getContent/646265

- Intel(R) Ethernet Network Adapter E810-C-Q2T:
  https://cdrdv2.intel.com/v1/dl/getContent/722960


Some devices support hardware-generated timestamps. The ice driver uses these
timestamps to synchronize clocks on the platform and report precise timestamps
on packets. Use the following hwstamp_ctl command, which is available in the
linuxptp utility, to enable this setting:

# hwstamp_ctl -i <ethX> -t 1 -r 1


SyncE Support
-------------
On hardware that supports Synchronous Ethernet (SyncE), the ice driver has
interfaces that allow you to synchronize frequencies with other SyncE-supported
ports. After you manually configure SyncE, the device dynamically selects the
best quality signal from the ones that are available. Then, once the signal is
locked, it synchronizes its frequency clock to it. The best quality signal is
determined based on the topology configured with the ice SyncE interfaces.

A detailed user guide is available for the following devices. Refer to it for
advanced configuration of this feature.
- Intel(R) Ethernet Network Adapter E810-XXV-4T:
  https://cdrdv2.intel.com/v1/dl/getContent/646265

- Intel(R) Ethernet Network Adapter E810-C-Q2T:
  https://cdrdv2.intel.com/v1/dl/getContent/722960


Tunnel/Overlay Stateless Offloads
---------------------------------
Supported tunnels and overlays include VXLAN, GENEVE, and others depending on
hardware and software configuration. Stateless offloads are enabled by default.
 
To view the current state of all offloads:

# ethtool -k <ethX>


UDP Segmentation Offload
------------------------
Allows the adapter to offload transmit segmentation of UDP packets with
payloads up to 64K into valid Ethernet frames. Because the adapter hardware is
able to complete data segmentation much faster than operating system software,
this feature may improve transmission performance.
In addition, the adapter may use fewer CPU resources.

NOTE:
- UDP transmit segmentation offload requires Linux kernel 4.18 or later.
- The application sending UDP packets must support UDP segmentation offload.

To enable/disable UDP Segmentation Offload, issue the following command:

# ethtool -K <ethX> tx-udp-segmentation [off|on]


Runtime Control of CRC/FCS Stripping
------------------------------------
The frame check sequence (FCS) is a four-octet cyclic redundancy check (CRC)
that allows the driver to detect corrupted data within a received Ethernet
frame.

The ice driver allows you to disable or enable FCS/CRC stripping using the
ethtool command.

NOTE:
- FCS/CRC stripping is enabled by default.
- The driver enforces valid combinations of FCS/CRC and VLAN stripping. You can
only disable FCS/CRC stripping if VLAN stripping is also disabled on the PF.
- Disabling FCS/CRC stripping may help when debugging issues. XDP programs can
also use FCS/CRC for their purposes.

Use the following ethtool command to enable or disable FCS/CRC stripping:

# ethtool -K <ethX> rx-fcs on|off

To check the status of FCS/CRC stripping, look for the 'rx-fcs' information
reported from ethtool:

# ethtool -k <ethX>


Using Devlink to update a device's NVM
--------------------------------------
When you update the NVM on some devices, the update may use the devlink
interface, rather than the ethtool interface. This will happen if the following
are true:
- You are updating an Intel Ethernet 800 Series device.
- Your system is running a distro that supports the "devlink dev flash" command.
- The firmware currently installed on the device supports it.
- The new NVM conforms to the correct PLDM format.

Most of the functionality and commands are the same with the following
exceptions:
- You cannot update a device in Recovery Mode. (To update a device in recovery
mode, you must download and install the Intel Ethernet driver set.)
- You cannot update the OROM or Netlist as a separate update, only as part of a
full NVM update.
- If you specified a preservation level of PRESERVE_ALL, the system will
immediately perform an EMPR reset after the NVM update.

On devices that support it, you can also use the devlink command line directly
to update the device NVM. However, we recommend that you use NVMUpdate.

# devlink dev flash pci/0000:3b:00.0 file filename.bin

Where :
- pci/0000:3b:00.0 – The device you wish to update. You can get a list of
devices with the "devlink dev info" command.
- filename.bin – The file that contains the new NVM image.


Port Split Configuration Using Devlink
--------------------------------------
Most CVL devices support changing their port split configuration to suit your
needs. For example, a dual port device may support two 100Gbps links, two 50
Gbps links, and (with the correct cables) four 25 Gbps links, etc. The
supported port split configurations are defined in the device's NVM. You can
use a tool like Intel's Ethernet Port Configuration Tool (EPCT) to query and
set this configuration. If no such tool is available, you can use devlink to
cycle through a device's possible prt split configurations. If you use devlink
to change the configuration, you must check the log to determine which
configuration was selected. If you use devlink, you specify the number of ports
you want configured on the device. Each time you call devlink with that port
count, the driver will check the device's current configuration and then move
to the next configuration with the specified number of ports. For example, if
your device has two four-port configurations defined in its NVM, the first time
you called devlink, it would select the first configuration. The second time
you called devlink, it would select the second configuration. If you called
devlink again, it would select the first configuration. There is no direct
feedback mechanism; you must check the log to determine which configuration was
set. Use the following command:

# devlink port split <pci/D:b:d.f>/0 count <num>

Where:
- <pci/D:b:d.f>/0 is the PCI address of the device
(pci/Domain:bus:device.function). /0 is the PORT_INDEX
- <num> is the desired port split count.

NOTES:
- If you successfully change a port's configuration, the driver logs an
information message: "Reboot required to finish port split" and the port split
configuration selected. This is the only indication of success.
- If you request an unsupported count value parameter in devlink port split,
the driver logs an information message: "Port split requested unsupported port
config".
- If you try to change the configuration on a PF that is not PF 0, the driver
returns the error "Port cannot be split."

For example, if your device had the following configurations defined in its NVM:

ice 0000:16:00.0:  Status  Split      Quad 0        _ Quad 1
ice 0000:16:00.0:          count  L0  L1  L2  L3  L4  L5  L6  L7
ice 0000:16:00.0: Active   2     100   -   -   - 100   -   -   -
ice 0000:16:00.0:          2      50   -  50   -   -   -   -   -
ice 0000:16:00.0:          4      25  25  25  25   -   -   -   -
ice 0000:16:00.0:          4      25  25   -   -  25  25   -   -
ice 0000:16:00.0:          8      10  10  10  10  10  10  10  10
ice 0000:16:00.0:          1     100   -   -   -   -   -   -   -

If you call

# devlink port split pci/0000.16:00.0/0 count 4

Your device will be configured for

ice 0000:16:00.0:          4      25  25  25  25   -   -   -   -

If you call the same command again, your device will be configured for

ice 0000:16:00.0:          4      25  25   -   -  25  25   -   -

If you call the same command a third time, your device will cycle back to the
top of its 4-port configurations (because there are only two 4-port
configurations defined it its NVM) and will be set to

ice 0000:16:00.0:          4      25  25  25  25   -   -   -   -


Firmware Logs
-------------
The ice driver allows you to generate firmware logs for supported categories of
events, to help debug issues with Customer Support. Firmware logs are enabled
by default. Refer to the Intel(R) Ethernet Adapters and Devices User Guide for
an overview of this feature and additional tips.

At a high level, you must do the following to capture a firmware log:

1. Set the configuration for the firmware log.
2. Perform the necessary steps to generate the issue you are trying to debug.
3. Capture the firmware log.
4. Stop capturing the firmware log.
5. Reset your firmware log settings as needed.
6. Work with Customer Support to debug your issue.

NOTE: Firmware logs are generated in a binary format and must be decoded by
Customer Support. Information collected is related only to firmware and
hardware for debug purposes.

Firmware logs are printed to dmesg. The driver groups these events into
categories, called "modules." Supported modules include:
* 00000001 - General (Bit 0)
* 00000002 - Control (Bit 1)
* 00000004 - Link Management (Bit 2)
* 00000008 - Link Topology Detection (Bit 3)
* 00000010 - Link Control Technology (Bit 4)
* 00000020 - I2C (Bit 5)
* 00000040 - SDP (Bit 6)
* 00000080 - MDIO (Bit 7)
* 00000100 - Admin Queue (Bit 8)
* 00000200 - Host DMA (Bit 9)
* 00000400 - LLDP (Bit 10)
* 00000800 - DCBx (Bit 11)
* 00001000 - DCB (Bit 12)
* 00002000 - XLR (function-level resets; Bit 13)
* 00004000 - NVM (Bit 14)
* 00008000 - Authentication (Bit 15)
* 00010000 - VPD (Vital Product Data; Bit 16)
* 00020000 - IOSF (Intel On-Chip System Fabric, Bit 17)
* 00040000 - Parser (Bit 18)
* 00080000 - Switch (Bit 19)
* 00100000 - Scheduler (Bit 20)
* 00200000 - TX Queue Management (Bit 21)
* 00400000 - ACL (Access Control List; Bit 22)
* 00800000 - Post (Bit 23)
* 01000000 - Watchdog (Bit 24)
* 02000000 - Task Dispatcher (Bit 25)
* 04000000 - Manageability (Bit 26)
* 08000000 - SyncE (Bit 27)
* 10000000 - Health (Bit 28)
* 20000000 - Time Sync (Bit 29)
* 40000000 - PF Registration (Bit 30)
* 80000000 - Module Version (Bit 31)

You can change the verbosity level of the firmware logs. You can set only one
log level per module, and each level includes the verbosity levels lower than
it. For instance, setting the level to "normal" will also log warning and error
messages. Available verbosity levels are:
 0 = none
 1 = error
 2 = warning
 3 = normal
 4 = verbose

NOTE:
- Firmware logs can overrun the dmesg buffer. Before loading the driver,
redirect dmesg to a file.
- Use a bitmap to set the desired verbosity level for the module(s). NOTE: You
must have dynamic debug enabled in the kernel.
- You cannot change firmware log parameters at runtime. You must reload the
driver for changes to take effect.

Do the following to capture a firmware log in Linux:

1. Remove the driver:

# rmmod ice

2. Redirect the firmware log from dmesg to a file:

# dmesg -w > filename.log

3. Load the driver using the following command, changing the events and level
values as needed:

# sudo insmod ice.ko dyndbg="+p" fwlog_events=<bitmask> fwlog_level=<level 0-4>

4. Perform the necessary steps to generate the issue you are trying to debug.

5. Work with Customer Support to decode your firmware log file and debug the
issue.

NOTE: To disable firmware logging completely, remove the driver and reload it.
Firmware logging will remain disabled until you enable it again.

CODE EXAMPLES:
To set all events to log warning messages, use the following command:

# sudo insmod ice.ko dyndbg="+p" fwlog_events=0x0FFFFFFF fwlog_level=2

To log verbose, normal, warning, and error messages for the ACL (Bit 22),
Switch (Bit 19), and Parser (Bit 18) modules, for example, use the following:

# sudo insmod ice.ko dyndbg="+p" fwlog_events=0x4C0000 fwlog_level=4

To dump the firmware logging configuration to dmesg, use the following commands:

# echo dump fwlog > command
# dmesg


Hierarchical QoS (HQoS) Transmit Scheduler
------------------------------------------
You can configure a custom transmit scheduler tree structure to shape transmit
traffic for specific needs. You change the tree structure by creating parent
nodes on the device and then assigning child nodes (VFs)to the parent node. You
can also change the transmit rate management configuration for each node.

NOTES:
- Reconfiguring the scheduler topology should only be done by an expert.
Modifying the scheduler topology may adversly impact your device's network
availability and throughput. Do not do this unless you are willing to take
these risks. After modifying the scheduler topology, if your device does not
perform as expected, you should return the device to the default topology.
- Modifying the Hierarchical QoS (HQoS) Transmit Scheduler requires Kernel 6.2,
or later.
- Modifying the Hierarchical QoS (HQoS) Transmit Scheduler is not compatible
with ADQ, DCB, RDMA, or other custom scheduler tree features.

To create a devlink-rate parent group:
# devlink port function rate add <dev/port>/<group>
where <dev/port> is the pci bus:device:function of the device
<group> is a new parent group

For example:
# devlink port function rate add pci/0000:03:00.0/operators
creates the "operators" group on the specified device

To create a new child node in a parent group:
# devlink port function rate add <dev/port>/<child> parent <group>
where <dev/port> is the pci bus:device:function of the device
<child> is a new child node
<group> is an existing parent group
For example:
# devlink port function rate add pci/0000:03:00.0/class_1 parent operators
creates the "class_1" child node in the "operators" parent group.

To display a device's current tree structure:
# devlink port function rate show <dev/port>
where <dev/port> is the pci bus:device:function of the device
For example:
# devlink port function rate show pci/0000:03:00.0

Example output:
pci/0000:03:00.0/node_0 type node (root)
pci/0000:03:00.0/operators type node tx_share 20Mbit tx_max 100Mbit tx_priority
2 tx_weight 5
pci/0000:03:00.0/class_1 type node parent operators
pci/0000:03:00.0/1 type leaf parent class_1
Refer to the devlink-rate MAN page and other documentation for details.



Performance Optimization
========================
Driver defaults are meant to fit a wide variety of workloads, but if further
optimization is required, we recommend experimenting with the following
settings.


Transmit/Receive Queue Allocation
---------------------------------
The driver allocates a number of transmit/receive queue pairs equal to the
number of local node CPU threads with the following constraints:
* The driver will allocate a minimum of 8 queue pairs, or the total number of
CPUs, whichever is lower
* The driver will allocate a maximum of 64 queue pairs. Or 256 for the iavf
driver.

You can set the number of queues symmetrical or asymmetrical using the ethtool
-L command. For example:
Setting 16 queue pairs for the interface
   # ethtool -L <ethX> combined 16
   # ethtool -L <ethX> tx 16 rx 16

Setting 16 Tx queues and 8 Rx queues
   # ethtool -L <ethX> tx 16 rx 8

NOTE: You cannot configure less than 1 Rx or 1 Tx queue. Attempts to do so will
be rejected by the driver.
NOTE: You cannot configure more Tx/Rx queues than there are MSI-X interrupts
available. Attempts to do so will be rejected by the driver.


IRQ to Adapter Queue Alignment
------------------------------
Pin the adapter's IRQs to specific cores by disabling the irqbalance service
and using the included set_irq_affinity script. Please see the script's help
text for further options.

 - The following settings will distribute the IRQs across all the cores
   evenly:

   # scripts/set_irq_affinity -x all <interface1> , [ <interface2>, ... ]

 - The following settings will distribute the IRQs across all the cores that
   are local to the adapter (same NUMA node):

   # scripts/set_irq_affinity -x local <interface1> ,[ <interface2>, ... ]

 - For very CPU-intensive workloads, we recommend pinning the IRQs to all
   cores.


Rx Descriptor Ring Size
-----------------------
To reduce the number of Rx packet discards, increase the number of Rx
descriptors for each Rx ring using ethtool.

 - Check if the interface is dropping Rx packets due to buffers being full
   (rx_dropped.nic can mean that there is no PCIe bandwidth):

   # ethtool -S <ethX> | grep "rx_dropped"

 - If the previous command shows drops on queues, it may help to increase
   the number of descriptors using 'ethtool -G':

   # ethtool -G <ethX> rx <N>
   Where <N> is the desired number of ring entries/descriptors

   This can provide temporary buffering for issues that create latency while
   the CPUs process descriptors.



Interrupt Rate Limiting
-----------------------
This driver supports an adaptive interrupt throttle rate (ITR) mechanism that
is tuned for general workloads. The user can customize the interrupt rate
control for specific workloads, via ethtool, adjusting the number of
microseconds between interrupts.

To set the interrupt rate manually, you must disable adaptive mode:

# ethtool -C <ethX> adaptive-rx off adaptive-tx off

For lower CPU utilization:
 - Disable adaptive ITR and lower Rx and Tx interrupts. The examples below
   affect every queue of the specified interface.

 - Setting rx-usecs and tx-usecs to 80 will limit interrupts to about
   12,500 interrupts per second per queue:

   # ethtool -C <ethX> adaptive-rx off adaptive-tx off rx-usecs 80
   tx-usecs 80

For reduced latency:
 - Disable adaptive ITR and ITR by setting rx-usecs and tx-usecs to 0
   using ethtool:

   # ethtool -C <ethX> adaptive-rx off adaptive-tx off rx-usecs 0
   tx-usecs 0

Per-queue interrupt rate settings:
 - The following examples are for queues 1 and 3, but you can adjust other
   queues.

 - To disable Rx adaptive ITR and set static Rx ITR to 10 microseconds or
   about 100,000 interrupts/second, for queues 1 and 3:

   # ethtool --per-queue <ethX> queue_mask 0xa --coalesce adaptive-rx off
   rx-usecs 10

 - To show the current coalesce settings for queues 1 and 3:

   # ethtool --per-queue <ethX> queue_mask 0xa --show-coalesce

Bounding interrupt rates using rx-usecs-high:
 - Valid Range: 0-236 (0=no limit)

   The range of 0-236 microseconds provides an effective range of 4,237 to
   250,000 interrupts per second. The value of rx-usecs-high can be set
   independently of rx-usecs and tx-usecs in the same ethtool command, and is
   also independent of the adaptive interrupt moderation algorithm. The
   underlying hardware supports granularity in 4-microsecond intervals, so
   adjacent values may result in the same interrupt rate.

 - The following command would disable adaptive interrupt moderation, and allow
   a maximum of 5 microseconds before indicating a receive or transmit was
   complete. However, instead of resulting in as many as 200,000 interrupts per
   second, it limits total interrupts per second to 50,000 via the rx-usecs-high
   parameter.

   # ethtool -C <ethX> adaptive-rx off adaptive-tx off rx-usecs-high 20
   rx-usecs 5 tx-usecs 5


Virtualized Environments
------------------------
In addition to the other suggestions in this section, the following may be
helpful to optimize performance in VMs.

 - Using the appropriate mechanism (vcpupin) in the VM, pin the CPUs to
   individual LCPUs, making sure to use a set of CPUs included in the
   device's local_cpulist: /sys/class/net/<ethX>/device/local_cpulist.

 - Configure as many Rx/Tx queues in the VM as available. (See the iavf driver
   documentation for the number of queues supported.) For example:

   # ethtool -L <virt_interface> rx <max> tx <max>


Transmit Balancing
------------------
Some Intel(R) Ethernet 800 Series devices allow you to enable a transmit
balancing feature to improve transmit performance under certain conditions.
When the feature is enabled, you should experience more consistent transmit
performance across queues and/or PFs and VFs.

By default, transmit balancing is disabled in the NVM. To enable this feature,
use one of the following to persistently change the setting for the device:
- Use the Ethernet Port Configuration Tool (EPCT) to enable the tx_balancing
option. Refer to the EPCT readme for more information.
- Enable the Transmit Balancing device setting in UEFI HII.
- Enable transmit balancing via Linux devlink (see below).

When the driver loads, it reads the transmit balancing setting from the NVM and
configures the device accordingly.

NOTE:
- The user selection for transmit balancing in EPCT, HII, or Linux devlink is
persistent across reboots. You must reboot the system for the selected setting
to take effect.
- This setting is device wide.
- The driver, NVM, and DDP package must all support this functionality to
enable the feature.

To set the transmit balancing feature via devlink:

# devlink dev param set <pci/D:b:d.f> name txbalancing value <setting> cmode
permanent

Where:
- <pci/D:b:d.f> is the PCI address of the PF.
- <setting> is true to enable transmit balancing, or false to disable transmit
balancing.

To show the current transmit balancing setting:

# devlink dev param show [ <pci> name txbalancing ]


MSI-X Vector Allocation
-----------------------
The ice driver automatically allocates MSI-X vectors for PF, VF, and RDMA from
a pool of 2048 vectors. If there are 8, or fewer, local node CPU threads, the
driver will automatically allocate 8 vectors for each PF. This scales up by
allocating one vector per local node CPU thread, up to 64 vectors. The driver
will not automatically allocate more than 64 MSI-X vectors for each PF. RDMA
requires one more MSI-X vector than the PF allocation, so the driver will
automatically allocation 9-65 MSI-X vectors for RDMA.

Setting MSI-X Vector Allocation
-------------------------------
You can use sysfs to override the automatic MSI-X vector allocation for a
particular PF or RDMA function, or for the pool of vectors used by the VFs
bound to a PF.

# devlink resource set <pci/D:b:d.f> msix/<parameter> size <num>

Where:
- <pci/D:b:d.f> is the PCI address of the device
(pci/Domain:bus:device.function)
- <parameter> is one of the following:
  * For a PF use the msix_eth parameter
  * For an RDMA function use the msix_rdma parameter
  * For the pool of vectors used by the VFs use the msix_vf parameter
- <num> is the number of MSI-X vector to assign to the function

For example, to set a PF to use 320 MSI-X vectors:

# devlink resource set pci/0000:31:00.1 msix/msix_eth size 320

NOTE: For this change to take affect you must reinitialize the driver after you
make this change. Reinitializing the driver may drop some netdev
configurations, including reset or downtime. Refer to the Devlink Reload
documentation for more information.

You can set the allocation for a particular VF with the sriov_vf_msix_count
sysfs parameter.

# echo <num> > /sys/bus/pci/devices/D:b:d.f/sriov_vf_msix_count

Where:
- <D:b:d.f> is the PCI address of the device (Domain:bus:device.function)
- <num> is the number of MSI-X vector allocate to the particular VF

For example, to set a VF to 64 MSI-X vectors, use

# echo 64 > /sys/bus/pci/devices/0000:31:00.2/sriov_vf_msix_count

Current MSI-X Allocation
------------------------
You can check the current MSI-X vector allocation by using the devlink resource
show parameter. For example:

# devlink resource show pci/0000:31:00.1

Might return:

  name: msix size 520 occ 262 unit entry dpipe_tables none
  resources:
    name msix_misc size 4 unit entry dpipe_tables none
    name: msix_eth size 48 occ 24 unit
    name: msix_vf size 48 occ 24 unit
    name: msix_rdma size 48 occ 24 unit

Increasing the automatic allocation limit
-----------------------------------------
The ice driver supports changing the automatic MSI-X vector allocation for PFs
and VFs to spread the RSS load across more cores. Each PF has its own LUT,
while all VFs use the global LUT. Each PF LUT allows for 2048 MSI-X vectors.
The VF default is a limit of 64 MSI-X vectors, but you can increase this to 512
vectors if there are enough resources in the global LUT. You can also assign a
PF's LUT to a bound VF, increasing the VF's MSI-X vector limit to 2048, but
decreasing the PF's limit to 512. Use the rss_lut_pf_attr and rss_lut_vf_attr
sysfs parameters to manage this.

NOTES:
- Before changing rss_lut_vf_attr, you must first set sriov_drivers_autoprobe
to zero. After changing rss_lut_vf_attr, you can set sriov_drivers_autoprobe
back to 1.
- You must reload the iavf driver after making these changes.

Set a VF's limit to 512, using the global LUT:
# echo 0 > /sys/bus/pci/devices/<ethx>/sriov_drivers_autoprobe
# echo 512 > /sys/bus/pci/devices/<ethx>/rss_lut_vf_attr

Set a VF to use its PF's LUT:
# echo 0 > /sys/bus/pci/devices/<ethx>/sriov_drivers_autoprobe
# echo 512 > /sys/bus/pci/devices/<ethx>/rss_lut_pf_attr
# echo 2048 > /sys/bus/pci/devices/<ethx>/rss_lut_vf_attr

Set a PF back to using its PF LUT.
# echo 0 > /sys/bus/pci/devices/<ethx>/sriov_drivers_autoprobe
# echo 512 > /sys/bus/pci/devices/<ethx>/rss_lut_vf_attr
# echo 2048 > /sys/bus/pci/devices/<ethx>/rss_lut_pf_attr


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

Receive Error counts may be higher than the actual packet error count
---------------------------------------------------------------------
When a packet is received with more than one error, two bad packets may be
reported. This affects all devices based on 10G, or faster, controllers.


Dynamic Debug
-------------
If you encounter unexpected issues during driver load, some of the most useful
information for developers to receive in a bug report can include driver
logging. This logging uses a kernel feature called Dynamic Debug, which is
generally enabled in most kernel configurations (CONFIG_DYNAMIC_DEBUG=y).

To load the driver with dynamic debug enabled, run modprobe with the dyndbg
parameter:

# modprobe ice dyndbg=+p

The driver will then load and print debugging information into the kernel log
(dmesg) and is usually logged into the system log viewable by journalctl or in
/var/log/messages. Saving this information to a file and attaching it to any
bug report can help shorten the reproduction and debugging time for a developer.

To enable dynamic debug during runtime operation of the driver, use this
command:

# echo "module ice +p" > /sys/kernel/debug/dynamic_debug/control

For more details, see the Dynamic Debug documentation included in the Linux
kernel instructions.


PF Message Queue Overflow
-------------------------
The device driver can detect some types of anomalous behavior. When it does, it
will log the VF MAC address and associated PF MAC address. Using this
information, you can check the virtual machine (VM) that is using the VF MAC
address to ensure that the VM is operating correctly.


'ethtool -S' does not display Tx/Rx packet statistics
-----------------------------------------------------
Issuing the command 'ethtool -S' does not display Tx/Rx packet statistics. This
is by convention. Use other tools (such as the 'ip' command) that display
standard netdev statistics such as Tx/Rx packet statistics.


'ethtool -S' rx_bytes and ip stats rx_bytes don't match statistics
------------------------------------------------------------------
The rx_bytes value of ethtool does not match the rx_bytes value of Netdev, due
to the 4-byte CRC being stripped by the device. The difference between the two
rx_bytes values will be 4 x the number of Rx packets. For example, if Rx
packets are 10 and Netdev (software statistics) displays rx_bytes as "X", then
ethtool (hardware statistics) will display rx_bytes as "X+40" (4 bytes CRC x 10
packets).


Unexpected Issues when the device driver and DPDK share a device
----------------------------------------------------------------
Unexpected issues may result when an ice device is in multi driver mode and the
kernel driver and DPDK driver are sharing the device. This is because access to
the global NIC resources is not synchronized between multiple drivers. Any
change to the global NIC configuration (writing to a global register, setting
global configuration by AQ, or changing switch modes) will affect all ports and
drivers on the device. Loading DPDK with the "multi-driver" module parameter
may mitigate some of the issues.


Fiber optics and auto-negotiation
---------------------------------
Modules based on 100GBASE-SR4, active optical cable (AOC), and active copper
cable (ACC) do not support auto-negotiation per the IEEE specification. To
obtain link with these modules, you must turn off auto-negotiation on the link
partner's switch ports.


'ethtool -a' autonegotiate result may vary between drivers
----------------------------------------------------------
For kernel versions 4.6 or higher, 'ethtool -a' will show the advertised and
negotiated autoneg settings. For kernel versions below 4.6, ethtool will only
report the negotiated link status.

The issue is cosmetic and does not affect functionality. Installing the latest
ice driver and upgrading your kernel to version 4.6 or higher will resolve the
issue.


AF_XDP fails to allocate buffers
--------------------------------
On kernels older than 5.3, you may see an undesirable CPU load during packet
processing if you enable AF_XDP in native mode and the Rx ring size is larger
than the UMEM fill queue. This is due to a known issue in the kernel and was
fixed in 5.3. To address the issue, upgrade your kernel to 5.3 or newer.


SCTP checksum offloads aren't indicated on Geneve tunnel
--------------------------------------------------------
For SCTP traffic over a Geneve tunnel, the SCTP checksum isn't offloaded to the
device, even when tx-checksum-sctp is on. This is due to a limitation in the
Linux kernel. However, for Rx traffic, the SCTP checksum is verified if
rx-checksumming is on. For both Tx and Rx traffic, you can offload the outer
UDP checksum to the device.


CentOS 7.2 Issues
-----------------
The following issues are specific to CentOS 7.2. Upgrading to the latest
version of the operating system will resolve these issues.
- base-r-fec mode is supposed to be on by default. On CentOS 7.2, Ethtool
--show-priv-flags shows that it is off, instead of on.
- ethtool -m <ethX> does not display optical module information as expected.
- You cannot create an ipv6 Intel(R) Ethernet Flow Director rule. For example:
# ethtool -U p1p1 flow-type tcp6 src-ip 3001:1::2:1:1 dst-ip 3001:1::1:1:1
src-port 22 dst-port 23 action 10
Returns a bad syntax error.


Incorrect link speed reported on older VF drivers
-------------------------------------------------
Linux distributions with older iavf or i40evf drivers (including Red Hat
Enterprise Linux 8) may show an incorrect link speed on VF interfaces. This
issue is cosmetic and does not affect VF functionality. To resolve the issue,
download the latest iavf driver.


Older VF drivers on Intel Ethernet 800 Series adapters
------------------------------------------------------
Some Windows* VF drivers from Release 22.9 or older may encounter errors when
loaded on a PF based on the Intel Ethernet 800 Series on Linux KVM. You may see
errors and the VF may not load. This issue does not occur starting with the
following Windows VF drivers:
- v40e64, v40e65: Version 1.5.65.0 and newer

To resolve this issue, download and install the latest iavf driver.


'VF X failed opcode 24' error message in dmesg on host
------------------------------------------------------
With a Microsoft Windows Server 2019 guest machine running on a Linux host, you
may see 'VF <vf_number> failed opcode 24' error messages in dmesg on the host.
This error is benign and does not affect traffic. Installing the latest iavf
driver in the guest will resolve the issue.


Windows guest OSs on a Linux host may not pass traffic across VLANs
-------------------------------------------------------------------
The VF is not aware of the VLAN configuration if you use Load Balancing and
Failover (LBFO) to configure VLANs in a Windows guest. VLANs configured using
LBFO on a VF driver may result in failure to pass traffic.


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.


MDD events in dmesg when creating maximum number of VLANs on the VF
-------------------------------------------------------------------
When you create the maximum number of VLANs on the VF, you may see MDD events
in dmesg on the host. This is due to the asynchronous design of the iavf
driver. It always reports success to any VLAN requests, but the requests may
fail later. The guest OS could try to send traffic on a VLAN that is not
configured on the VF, which will cause a Malicious Driver Detection (MDD) event
in dmesg on the host.

This issue is cosmetic. You do not need to reload the PF driver.


'ip address' or 'ip link' command displays an error on a single-port NIC
with 245+ VFs
------------------------------------------------------------------------
When you use the 'ip address' or 'ip link' command on a Linux host configured
with 245 or more VFs on a single-port adapter, you may encounter a "Buffer too
small for object" error. This is due to a known issue in the iproute2 tools.
Please use ifconfig instead of iproute2. You can install ifconfig via the
net-tools-deprecated package.


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) 2017 - 2023 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.