.\"-
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.Dd May 21, 2024
.Dt IAVF 4
.Os
.Sh NAME
.Nm iavf
.Nd "Intel Ethernet Adaptive Virtual Function Driver"
.Sh SYNOPSIS
To compile this driver into the kernel, place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device iflib"
.Cd "device iavf"
.Ed
.Pp
To load the driver as a module at boot time, place the following lines in
.Xr loader.conf 5 :
.Bd -literal -offset indent
if_iavf_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides support for any PCI Virtual Function created from certain
Intel Ethernet devices.
This driver is compatible with virtual functions bound to devices based on the
following:
.Pp
.Bl -bullet -compact
.It
Intel\(rg Ethernet Controller E810\-C
.It
Intel\(rg Ethernet Controller E810\-XXV
.It
Intel\(rg Ethernet Connection E822\-C
.It
Intel\(rg Ethernet Connection E822\-L
.It
Intel\(rg Ethernet Connection E823\-C
.It
Intel\(rg Ethernet Connection E823\-L
.It
Intel\(rg Ethernet Controller I710
.It
Intel\(rg Ethernet Controller X710
.It
Intel\(rg Ethernet Controller XL710
.It
Intel\(rg Ethernet Network Connection X722
.It
Intel\(rg Ethernet Controller XXV710
.It
Intel\(rg Ethernet Controller V710
.El
.Pp
The associated Physical Function (PF) drivers for this VF driver are:
.Pp
.Bl -bullet -compact
.It
.Xr ice 4
.It
.Xr ixl 4
.El
.Pp
For questions related to hardware requirements, refer to the documentation
supplied with your Intel Ethernet Adapter.
All hardware requirements listed apply to use with
.Fx .
.Ss The VF Driver
The VF driver is normally used in a virtualized environment where a host driver
manages SR\-IOV, and provides a VF device to the guest.
.Pp
In the
.Fx
guest, the iavf driver would be loaded and will function using
the VF device assigned to it.
.Pp
The VF driver provides most of the same functionality as the core driver, but
is actually a subordinate to the host.
Access to many controls is accomplished by a request to the host via what is
called the "Admin queue."
These are startup and initialization events, however; once in operation, the
device is self\-contained and should achieve near native performance.
.Pp
Some notable limitations of the VF environment:
.Bl -bullet
.It
The PF can configure the VF to allow promiscuous mode, using a configuration
parameter in
.Xr iovctl.conf 5 ;
otherwise, promiscuous mode will not work
.It
Media info is not available from the PF, so the active media will always be
displayed as auto in
.Xr ifconfig 8
.El
.Ss Adaptive Virtual Function
Adaptive Virtual Function (AVF) allows the virtual function driver, or VF, to
adapt to changing feature sets of the physical function driver (PF) with which
it is associated.
This allows system administrators to update a PF without having to update all
the VFs associated with it.
All AVFs have a single common device ID and branding string.
.Pp
AVFs have a minimum set of features known as "base mode," but may provide
additional features depending on what features are available in the PF with
which the AVF is associated.
The following are base mode features:
.Bl -bullet -compact
.It
4 Queue Pairs (QP) and associated Configuration Status Registers (CSRs)
for Tx/Rx
.It
iavf descriptors and ring format
.It
Descriptor write\-back completion
.It
1 control queue, with iavf descriptors, CSRs and ring format
.It
5 MSI\-X interrupt vectors and corresponding iavf CSRs
.It
1 Interrupt Throttle Rate (ITR) index
.It
1 Virtual Station Interface (VSI) per VF
.It
1 Traffic Class (TC), TC0
.It
Receive Side Scaling (RSS) with 64 entry indirection table and key,
configured through the PF
.It
1 unicast MAC address reserved per VF
.It
8 MAC address filters for each VF on an Intel\(rg Ethernet 800 Series device
.It
16 MAC address filters for each VF on an Intel\(rg Ethernet 700 Series device
.It
Stateless offloads \- non\-tunneled checksums
.It
AVF device ID
.It
HW mailbox is used for VF to PF communications
.El
.Sh CONFIGURATION AND TUNING
.Ss Important System Configuration Changes
It is important to note that 100G operation can generate high
numbers of interrupts, often incorrectly being interpreted as
a storm condition in the kernel.
It is suggested that this be resolved by setting
.Va hw.intr_storm_threshold
to 0.
.Pp
The default is 1000.
.Pp
Best throughput results are seen with a large MTU; use 9706 if possible.
The default number of descriptors per ring is 1024.
Increasing this may improve performance, depending on your use case.
.Ss Configuring for no iflib
.Xr iflib 4
is a common framework for network interface drivers for
.Fx
that uses a shared set of sysctl names.
.Pp
The default
.Nm
driver depends on it, but it can be compiled without it.
.Ss Jumbo Frames
Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU)
to a value larger than the default value of 1500.
.Pp
Use the
.Xr ifconfig 8
command to increase the MTU size.
.Pp
To confirm the MTU used between two specific devices, use
.Xr route 8 :
.Bd -literal -offset indent
route get <destination_IP_address>
.Ed
.Pp
NOTE:
.Bl -bullet
.It
The maximum MTU setting for jumbo frames is 9706.
This corresponds to the maximum jumbo frame size of 9728 bytes.
.It
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.
.It
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.
.El
.Ss Checksum Offload
Checksum offloading supports both TCP and UDP packets and is supported for both
transmit and receive.
.Pp
TSO (TCP Segmentation Offload) supports both IPv4 and IPv6.
Both of these features are enabled and disabled via
.Xr ifconfig 8 .
.Pp
NOTE:
.Bl -bullet -compact
.It
TSO requires Tx checksum; if Tx checksum is disabled then TSO will also
be disabled.
.El
.Ss LRO
LRO (Large Receive Offload) may provide Rx performance improvement.
However, it is incompatible with packet\-forwarding workloads.
You should carefully evaluate the environment and enable LRO when possible.
.Ss Rx and Tx Descriptor Rings
Allows you to set the Rx and Tx descriptor rings independently.
Set them via these
.Xr iflib 4
sysctls:
.Bl -tag -width indent
.It dev.iavf.#.iflib.override_nrxds
.It dev.iavf.#.iflib.override_ntxds
.El
.Ss Link\-Level Flow Control (LFC)
The VF driver does not have access to flow control settings.
It must be managed from the host side.
.Sh SEE ALSO
.Xr arp 4 ,
.Xr ice 4 ,
.Xr iflib 4 ,
.Xr ixl 4 ,
.Xr netintro 4 ,
.Xr vlan 4 ,
.Xr ifconfig 8
.Pp
See the
.Dq Intel\(rg Ethernet Adapters and Devices User Guide
for additional information on features.
It is available on the Intel website at either of the following:
.Bl -bullet
.It
.Lk https://cdrdv2.intel.com/v1/dl/getContent/705831
.It
.Lk https://www.intel.com/content/www/us/en/download/19373/adapter\-user\-guide\-for\-intel\-ethernet\-adapters.html
.El
.Pp
For information on how to identify your adapter, and for the latest Intel
network drivers, refer to the Intel Support website:
.Aq Lk http://www.intel.com/support
.Sh CAVEATS
.Ss Driver Buffer Overflow Fix
The fix to resolve CVE\-2016\-8105, referenced in Intel SA\-00069
.Aq Lk https://www.intel.com/content/www/us/en/security\-center/advisory/intel\-sa\-00069.html ,
is included in this and future versions of the driver.
.Ss Network Memory Buffer Allocation
.Fx
may have a low number of network memory buffers (mbufs) by default.
If your mbuf value is too low, it may cause the driver to fail to initialize
and/or cause the system to become unresponsive.
You can check to see if the system is mbuf\-starved by running
.Li "netstat -m" .
Increase the number of mbufs by editing the lines below in
.Xr sysctl.conf 5 :
.Bd -literal -offset indent
kern.ipc.nmbclusters
kern.ipc.nmbjumbop
kern.ipc.nmbjumbo9
kern.ipc.nmbjumbo16
kern.ipc.nmbufs
.Ed
.Pp
The amount of memory that you allocate is system specific, and may require
some trial and error.
Also, increasing the following in
.Xr sysctl.conf 5
could help increase
network performance:
.Bd -literal -offset indent
kern.ipc.maxsockbuf
net.inet.tcp.sendspace
net.inet.tcp.recvspace
net.inet.udp.maxdgram
net.inet.udp.recvspace
.Ed
.Ss UDP Stress Test Dropped Packet Issue
Under small packet UDP stress with the
.Nm
driver, the system may drop UDP packets due to socket buffers being full.
Setting the PF driver's Flow Control variables to the minimum may resolve the
issue.
.Ss Disable LRO when routing/bridging
LRO must be turned off when forwarding traffic.
.Sh SUPPORT
For general information, go to the Intel support website at
.Aq Lk http://www.intel.com/support/ .
.Pp
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
.Aq Mt freebsd@intel.com .
.Sh LEGAL
Intel\(rg is a trademark or registered trademark of Intel Corporation
or its subsidiaries in the United States and / or other countries.
.Pp
Other names and brands may be claimed as the property of others.
.Sh HISTORY
The
.Nm
device driver first appeared in
.Fx 10.1
under the name
.Nm ixlv .
It was converted to use
.Xr iflib 4
and renamed in
.Fx 12.4 .
.Sh AUTHORS
The
.Nm
driver was written by the
.An Intel Corporation Aq Mt freebsd@intel.com