FreeBSD manual
download PDF document: vtnet.4.pdf
VTNET(4) FreeBSD Kernel Interfaces Manual VTNET(4)
NAME
vtnet - VirtIO Ethernet driver
SYNOPSIS
To compile this driver into the kernel, place the following lines in your
kernel configuration file:
device vtnet
Alternatively, to load the driver as a module at boot time, place the
following line in loader.conf(5):
if_vtnet_load="YES"
DESCRIPTION
The vtnet device driver provides support for VirtIO Ethernet devices.
If the hypervisor advertises the appropriate features, the vtnet driver
supports TCP/UDP checksum offload for both transmit and receive, TCP
segmentation offload (TSO), TCP large receive offload (LRO), hardware
VLAN tag stripping/insertion features, a multicast hash filter, as well
as Jumbo Frames (up to 9216 bytes), which can be configured via the
interface MTU setting. Selecting an MTU larger than 1500 bytes with the
ifconfig(8) utility configures the adapter to receive and transmit Jumbo
Frames.
For more information on configuring this device, see ifconfig(8).
LOADER TUNABLES
Tunables can be set at the loader(8) prompt before booting the kernel or
stored in loader.conf(5).
hw.vtnet.csum_disable
hw.vtnet.X.csum_disable
This tunable disables receive and send checksum offload. The
default value is 0.
hw.vtnet.tso_disable
hw.vtnet.X.tso_disable
This tunable disables TSO. The default value is 0.
hw.vtnet.lro_disable
hw.vtnet.X.lro_disable
This tunable disables LRO. The default value is 0.
hw.vtnet.mq_disable
hw.vtnet.X.mq_disable
This tunable disables multiqueue. The default value is 0.
hw.vtnet.mq_max_pairs
hw.vtnet.X.mq_max_pairs
This tunable sets the maximum number of transmit and receive
SEE ALSO
arp(4), netintro(4), ng_ether(4), virtio(4), vlan(4), ifconfig(8)
HISTORY
The vtnet driver was written by Bryan Venteicher <bryanv@FreeBSD.org>.
It first appeared in FreeBSD 9.0.
CAVEATS
The vtnet driver only supports LRO when the hypervisor advertises the
mergeable buffer feature.
FreeBSD 14.0-RELEASE-p11 January 22, 2012 FreeBSD 14.0-RELEASE-p11