VIRTIO_BLK(4) BSD Kernel Interfaces Manual VIRTIO_BLK(4)NAME
virtio_blk -- VirtIO Block driver
SYNOPSIS
To compile this driver into the kernel, place the following lines in your kernel configuration file:
device virtio_blk
Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5):
virtio_blk_load="YES"
DESCRIPTION
The virtio_blk device driver provides support for VirtIO block devices.
LOADER TUNABLES
Tunables can be set at the loader(8) prompt before booting the kernel or stored in loader.conf(5).
hw.vtblk.no_ident
hw.vtblk.X.no_ident
These tunables disable retrieving the device identification string from the hypervisor either globally or per-device. The default
value is 0.
hw.vtblk.writecache_mode
hw.vtblk.X.writecache_mode
These tunables determine the write cache mode globally or per-device. The mode can changed only if the ConfigWCE feature is negoti-
ated. Set to 0 for writethrough mode, 1 for writeback mode, and -1 to leave it as-is. The default value is to leave as-is.
SYSCTL VARIABLES
The following variables are available as sysctl(8) variables.
dev.vtblk.X.writecache_mode
The write cache mode of the device can be either writethrough (0) or writeback (1). If the ConfigWCE feature is negotiated, the
write cache mode can be toggled between writethrough and writeback.
SEE ALSO virtio(4)HISTORY
The virtio_blk driver was written by Bryan Venteicher <bryanv@FreeBSD.org>. It first appeared in FreeBSD 9.0.
BSD July 2, 2013 BSD
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VTNET(4) BSD 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 appreciate features, the vtnet driver supports TCP/UDP checksum offload for both transmit and receive, TCP
segmentation offload (TSO), TCP large receive offload (LRO), and hardware VLAN tag stripping/insertion features, as well as 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 queue pairs. Multiple queues are only supported when the Multiqueue
feature is negotiated. This driver supports a maximum of 8 queue pairs. The number of queue pairs used is the lesser of the maximum
supported by the driver and the hypervisor, the number of CPUs present in the guest, and this tunable if not zero. The default value
is 0.
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.
BSD January 22, 2012 BSD