VIRTIO_BLK(4)          FreeBSD 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
             negotiated.  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.

FreeBSD 13.1-RELEASE-p6          July 2, 2013          FreeBSD 13.1-RELEASE-p6