1 .\" Copyright (c) 2011 Bryan Venteicher
2 .\" All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
7 .\" 1. Redistributions of source code must retain the above copyright
8 .\" notice, this list of conditions and the following disclaimer.
9 .\" 2. Redistributions in binary form must reproduce the above copyright
10 .\" notice, this list of conditions and the following disclaimer in the
11 .\" documentation and/or other materials provided with the distribution.
13 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 .Nd VirtIO Block driver
34 To compile this driver into the kernel,
35 place the following lines in your
36 kernel configuration file:
37 .Bd -ragged -offset indent
38 .Cd "device virtio_blk"
41 Alternatively, to load the driver as a
42 module at boot time, place the following line in
44 .Bd -literal -offset indent
50 device driver provides support for VirtIO block devices.
52 Tunables can be set at the
54 prompt before booting the kernel or stored in
56 .Bl -tag -width indent
57 .It Va hw.vtblk.no_ident
58 .It Va hw.vtblk. Ns Ar X Ns Va .no_ident
60 These tunables disable retrieving the device identification string
61 from the hypervisor either globally or per-device.
62 The default value is 0.
63 .It Va hw.vtblk.writecache_mode
64 .It Va hw.vtblk. Ns Ar X Ns Va .writecache_mode
66 These tunables determine the write cache mode globally or per-device.
67 The mode can changed only if the ConfigWCE feature is negotiated.
68 Set to 0 for writethrough mode, 1 for writeback mode, and -1 to leave
70 The default value is to leave as-is.
73 The following variables are available as
76 .Bl -tag -width indent
77 .It Va dev.vtblk. Ns Ar X Ns Va .writecache_mode
79 The write cache mode of the device can be either writethrough (0) or
81 If the ConfigWCE feature is negotiated, the write cache mode can
82 be toggled between writethrough and writeback.
90 .An Bryan Venteicher Aq bryanv@FreeBSD.org .