117905a98SSascha Wildner.\" Copyright (c) 2011 Bryan Venteicher 217905a98SSascha Wildner.\" All rights reserved. 317905a98SSascha Wildner.\" 417905a98SSascha Wildner.\" Redistribution and use in source and binary forms, with or without 517905a98SSascha Wildner.\" modification, are permitted provided that the following conditions 617905a98SSascha Wildner.\" are met: 717905a98SSascha Wildner.\" 1. Redistributions of source code must retain the above copyright 817905a98SSascha Wildner.\" notice, this list of conditions and the following disclaimer. 917905a98SSascha Wildner.\" 2. Redistributions in binary form must reproduce the above copyright 1017905a98SSascha Wildner.\" notice, this list of conditions and the following disclaimer in the 1117905a98SSascha Wildner.\" documentation and/or other materials provided with the distribution. 1217905a98SSascha Wildner.\" 1317905a98SSascha Wildner.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1417905a98SSascha Wildner.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1517905a98SSascha Wildner.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1617905a98SSascha Wildner.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1717905a98SSascha Wildner.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 1817905a98SSascha Wildner.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 1917905a98SSascha Wildner.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2017905a98SSascha Wildner.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2117905a98SSascha Wildner.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2217905a98SSascha Wildner.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2317905a98SSascha Wildner.\" SUCH DAMAGE. 2417905a98SSascha Wildner.\" 2558db6936SImre Vadasz.\" $FreeBSD: head/share/man/man4/virtio_blk.4 267938 2014-06-26 21:46:14Z bapt $ 2617905a98SSascha Wildner.\" 27*ec363e75SSascha Wildner.Dd December 10, 2014 2817905a98SSascha Wildner.Dt VIRTIO_BLK 4 2917905a98SSascha Wildner.Os 3017905a98SSascha Wildner.Sh NAME 3117905a98SSascha Wildner.Nm virtio_blk 3217905a98SSascha Wildner.Nd VirtIO Block driver 3317905a98SSascha Wildner.Sh SYNOPSIS 3417905a98SSascha WildnerTo compile this driver into the kernel, 3517905a98SSascha Wildnerplace the following lines in your 3617905a98SSascha Wildnerkernel configuration file: 3717905a98SSascha Wildner.Bd -ragged -offset indent 3817905a98SSascha Wildner.Cd "device virtio_blk" 3917905a98SSascha Wildner.Ed 4017905a98SSascha Wildner.Pp 4117905a98SSascha WildnerAlternatively, to load the driver as a 4217905a98SSascha Wildnermodule at boot time, place the following line in 4317905a98SSascha Wildner.Xr loader.conf 5 : 4417905a98SSascha Wildner.Bd -literal -offset indent 4517905a98SSascha Wildnervirtio_blk_load="YES" 4617905a98SSascha Wildner.Ed 4717905a98SSascha Wildner.Sh DESCRIPTION 4817905a98SSascha WildnerThe 4917905a98SSascha Wildner.Nm 5017905a98SSascha Wildnerdevice driver provides support for VirtIO block devices. 51*ec363e75SSascha Wildner.Sh FILES 52*ec363e75SSascha Wildner.Bl -tag -width ".Pa /dev/vbdX" -compact 53*ec363e75SSascha Wildner.It Pa /dev/vbdX 54*ec363e75SSascha Wildner.Nm 55*ec363e75SSascha Wildnerdevice nodes 56*ec363e75SSascha Wildner.El 5717905a98SSascha Wildner.Sh LOADER TUNABLES 5817905a98SSascha WildnerTunables can be set at the 5917905a98SSascha Wildner.Xr loader 8 6017905a98SSascha Wildnerprompt before booting the kernel or stored in 6117905a98SSascha Wildner.Xr loader.conf 5 . 6217905a98SSascha Wildner.Bl -tag -width "xxxxxx" 6358db6936SImre Vadasz.\".It Va hw.vtblk.no_ident 6458db6936SImre Vadasz.\".It Va hw.vtblk. Ns Ar X Ns Va .no_ident 6558db6936SImre Vadasz.\".Pp 6658db6936SImre Vadasz.\"These tunables disable retrieving the device identification string 6758db6936SImre Vadasz.\"from the hypervisor either globally or per-device. 6858db6936SImre Vadasz.\"The default value is 0. 6958db6936SImre Vadasz.It Va hw.vtblk.writecache_mode 7058db6936SImre Vadasz.It Va hw.vtblk. Ns Ar X Ns Va .writecache_mode 7158db6936SImre Vadasz.Pp 7258db6936SImre VadaszThese tunables determine the write cache mode globally or per-device. 7358db6936SImre VadaszThe mode can changed only if the ConfigWCE feature is negotiated. 7458db6936SImre VadaszSet to 0 for writethrough mode, 1 for writeback mode, and -1 to leave 7558db6936SImre Vadaszit as-is. 7658db6936SImre VadaszThe default value is to leave as-is. 7758db6936SImre Vadasz.El 7858db6936SImre Vadasz.Sh SYSCTL VARIABLES 7958db6936SImre VadaszThe following variables are available as 8058db6936SImre Vadasz.Xr sysctl 8 8158db6936SImre Vadaszvariables. 8258db6936SImre Vadasz.Bl -tag -width "xxxxxx" 8358db6936SImre Vadasz.It Va dev.vtblk. Ns Ar X Ns Va .writecache_mode 8458db6936SImre Vadasz.Pp 8558db6936SImre VadaszThe write cache mode of the device can be either writethrough (0) or 8658db6936SImre Vadaszwriteback (1). 8758db6936SImre VadaszIf the ConfigWCE feature is negotiated, the write cache mode can 8858db6936SImre Vadaszbe toggled between writethrough and writeback. 8917905a98SSascha Wildner.El 9017905a98SSascha Wildner.Sh SEE ALSO 9117905a98SSascha Wildner.Xr virtio 4 9217905a98SSascha Wildner.Sh HISTORY 9317905a98SSascha WildnerThe 9417905a98SSascha Wildner.Nm 9517905a98SSascha Wildnerdriver was written by 9658db6936SImre Vadasz.An Bryan Venteicher Aq Mt bryanv@FreeBSD.org . 9717905a98SSascha WildnerIt first appeared in 9817905a98SSascha Wildner.Fx 9.0 . 99