1.\" $NetBSD: viomb.4,v 1.2 2011/11/26 22:36:14 wiz Exp $ 2.\" $OpenBSD: viomb.4,v 1.2 2013/01/16 00:30:48 brad Exp $ 3.\" Copyright (c) 2012 Dinar Talypov <dinar@i-nk.ru> 4.\" Copyright (C) 2011 Minoura Makoto. 5.\" All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 22.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.Dd $Mdocdate: January 16 2013 $ 29.Dt VIOMB 4 30.Os 31.Sh NAME 32.Nm viomb 33.Nd VirtIO memory ballooning driver 34.Sh SYNOPSIS 35.Cd "viomb* at virtio?" 36.Sh DESCRIPTION 37The 38.Nm 39driver supports the virtio-compliant memory ballooning device. 40.Pp 41Memory ballooning works as follows: 42.Pp 43.Bl -enum -compact 44.It 45The host operator requests a guest to return some amount of memory to the host 46(via, for example, the QEMU monitor balloon command). 47.It 48The hypervisor sends the request via the VirtIO memory ballooning device. 49.It 50The guest 51.Nm 52driver requests allocation of that amount of physical memory from the 53.Ox 54memory management system. 55.It 56The 57.Nm 58device tells the hypervisor the guest physical memory address of the 59allocated memory via the VirtIO memory ballooning device. 60.El 61.Sh SEE ALSO 62.Xr intro 4 , 63.Xr virtio 4 64.Rs 65.%A Rusty Russell, IBM Corporation 66.%T Virtio PCI Card Specification 67.%U http://ozlabs.org/~rusty/virtio-spec/ 68.Re 69.Sh HISTORY 70The 71.Nm 72device driver first appeared in 73.Ox 5.3 . 74