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.

           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_random(4),
     virtio_scsi(4), vtnet(4)

HISTORY
     Support for VirtIO first appeared in FreeBSD 9.0.

AUTHORS
     FreeBSD support for VirtIO was first added by Bryan Venteicher
     <bryanv@FreeBSD.org>.

FreeBSD 13.1-RELEASE-p6          May 26, 2019          FreeBSD 13.1-RELEASE-p6