110b59a9bSPeter Grehan.\" Copyright (c) 2011 Bryan Venteicher 210b59a9bSPeter Grehan.\" All rights reserved. 310b59a9bSPeter Grehan.\" 410b59a9bSPeter Grehan.\" Redistribution and use in source and binary forms, with or without 510b59a9bSPeter Grehan.\" modification, are permitted provided that the following conditions 610b59a9bSPeter Grehan.\" are met: 710b59a9bSPeter Grehan.\" 1. Redistributions of source code must retain the above copyright 810b59a9bSPeter Grehan.\" notice, this list of conditions and the following disclaimer. 910b59a9bSPeter Grehan.\" 2. Redistributions in binary form must reproduce the above copyright 1010b59a9bSPeter Grehan.\" notice, this list of conditions and the following disclaimer in the 1110b59a9bSPeter Grehan.\" documentation and/or other materials provided with the distribution. 1210b59a9bSPeter Grehan.\" 1310b59a9bSPeter Grehan.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1410b59a9bSPeter Grehan.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1510b59a9bSPeter Grehan.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1610b59a9bSPeter Grehan.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1710b59a9bSPeter Grehan.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 1810b59a9bSPeter Grehan.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 1910b59a9bSPeter Grehan.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2010b59a9bSPeter Grehan.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2110b59a9bSPeter Grehan.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2210b59a9bSPeter Grehan.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2310b59a9bSPeter Grehan.\" SUCH DAMAGE. 2410b59a9bSPeter Grehan.\" 2510b59a9bSPeter Grehan.\" $FreeBSD$ 2610b59a9bSPeter Grehan.\" 27118619acSBryan Venteicher.Dd July 2, 2013 2810b59a9bSPeter Grehan.Dt VIRTIO_BLK 4 2910b59a9bSPeter Grehan.Os 3010b59a9bSPeter Grehan.Sh NAME 3110b59a9bSPeter Grehan.Nm virtio_blk 3210b59a9bSPeter Grehan.Nd VirtIO Block driver 3310b59a9bSPeter Grehan.Sh SYNOPSIS 3410b59a9bSPeter GrehanTo compile this driver into the kernel, 3510b59a9bSPeter Grehanplace the following lines in your 3610b59a9bSPeter Grehankernel configuration file: 3710b59a9bSPeter Grehan.Bd -ragged -offset indent 3810b59a9bSPeter Grehan.Cd "device virtio_blk" 3910b59a9bSPeter Grehan.Ed 4010b59a9bSPeter Grehan.Pp 4110b59a9bSPeter GrehanAlternatively, to load the driver as a 4210b59a9bSPeter Grehanmodule at boot time, place the following line in 4310b59a9bSPeter Grehan.Xr loader.conf 5 : 4410b59a9bSPeter Grehan.Bd -literal -offset indent 4510b59a9bSPeter Grehanvirtio_blk_load="YES" 4610b59a9bSPeter Grehan.Ed 4710b59a9bSPeter Grehan.Sh DESCRIPTION 4810b59a9bSPeter GrehanThe 4910b59a9bSPeter Grehan.Nm 5010b59a9bSPeter Grehandevice driver provides support for VirtIO block devices. 5110b59a9bSPeter Grehan.Sh LOADER TUNABLES 5210b59a9bSPeter GrehanTunables can be set at the 5310b59a9bSPeter Grehan.Xr loader 8 5410b59a9bSPeter Grehanprompt before booting the kernel or stored in 5510b59a9bSPeter Grehan.Xr loader.conf 5 . 56118619acSBryan Venteicher.Bl -tag -width indent 5710b59a9bSPeter Grehan.It Va hw.vtblk.no_ident 58118619acSBryan Venteicher.It Va hw.vtblk. Ns Ar X Ns Va .no_ident 59118619acSBryan Venteicher.Pp 60118619acSBryan VenteicherThese tunables disable retrieving the device identification string 61118619acSBryan Venteicherfrom the hypervisor either globally or per-device. 6228083eaaSChristian BruefferThe default value is 0. 63118619acSBryan Venteicher.It Va hw.vtblk.writecache_mode 64118619acSBryan Venteicher.It Va hw.vtblk. Ns Ar X Ns Va .writecache_mode 65118619acSBryan Venteicher.Pp 66118619acSBryan VenteicherThese tunables determine the write cache mode globally or per-device. 67118619acSBryan VenteicherThe mode can changed only if the ConfigWCE feature is negotiated. 68118619acSBryan VenteicherSet to 0 for writethrough mode, 1 for writeback mode, and -1 to leave 69118619acSBryan Venteicherit as-is. 70118619acSBryan VenteicherThe default value is to leave as-is. 71118619acSBryan Venteicher.El 72118619acSBryan Venteicher.Sh SYSCTL VARIABLES 73118619acSBryan VenteicherThe following variables are available as 74118619acSBryan Venteicher.Xr sysctl 8 75118619acSBryan Venteichervariables. 76118619acSBryan Venteicher.Bl -tag -width indent 77118619acSBryan Venteicher.It Va dev.vtblk. Ns Ar X Ns Va .writecache_mode 78118619acSBryan Venteicher.Pp 79118619acSBryan VenteicherThe write cache mode of the device can be either writethrough (0) or 80118619acSBryan Venteicherwriteback (1). 81118619acSBryan VenteicherIf the ConfigWCE feature is negotiated, the write cache mode can 82118619acSBryan Venteicherbe toggled between writethrough and writeback. 8310b59a9bSPeter Grehan.El 8410b59a9bSPeter Grehan.Sh SEE ALSO 8510b59a9bSPeter Grehan.Xr virtio 4 8610b59a9bSPeter Grehan.Sh HISTORY 8710b59a9bSPeter GrehanThe 8810b59a9bSPeter Grehan.Nm 8910b59a9bSPeter Grehandriver was written by 90*6c899950SBaptiste Daroussin.An Bryan Venteicher Aq Mt bryanv@FreeBSD.org . 9110b59a9bSPeter GrehanIt first appeared in 9210b59a9bSPeter Grehan.Fx 9.0 . 93