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VIRTIO(4) FreeBSD Kernel Interfaces Manual VIRTIO(4)
NAME
virtio - VirtIO Device Support
SYNOPSIS
To compile VirtIO device support into the kernel, place the following
lines in your kernel configuration file:
device virtio
device virtio_pci
Alternatively, to load VirtIO support as modules at boot time, place the
following lines in loader.conf(5):
virtio_load="YES"
virtio_pci_load="YES"
DESCRIPTION
VirtIO is a specification for para-virtualized I/O in a virtual machine
(VM). Traditionally, the hypervisor emulated real devices such as an
Ethernet interface or disk controller to provide the VM with I/O. This
emulation is often inefficient.
VirtIO defines an interface for efficient I/O between the hypervisor and
VM. The virtio module provides a shared memory transport called a
virtqueue. The virtio_pci device driver represents an emulated PCI
device that the hypervisor makes available to the VM. This device
provides the probing, configuration, and interrupt notifications needed
to interact with the hypervisor. FreeBSD supports the following VirtIO
devices:
Ethernet An emulated Ethernet device is provided by the vtnet(4)
device driver.
Block An emulated disk controller is provided by the
virtio_blk(4) device driver.
Console Provided by the virtio_console(4) driver.
Entropy Provided by the virtio_random(4) driver.
Balloon A pseudo-device to allow the VM to release memory back to
the hypervisor is provided by the virtio_balloon(4)
device driver.
GPU Graphics support is provided by the virtio_gpu(4) device
driver.
SCSI An emulated SCSI HBA is provided by the virtio_scsi(4)
device driver.
SEE ALSO
virtio_balloon(4), virtio_blk(4), virtio_console(4), virtio_gpu(4),
virtio_random(4), virtio_scsi(4), vtnet(4)
HISTORY
Support for VirtIO first appeared in FreeBSD 9.0.