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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 14.2-RELEASE July 2, 2013 FreeBSD 14.2-RELEASE