1.\" $FreeBSD: head/share/man/man4/hv_vmbus.4 276259 2014-12-26 22:30:18Z bapt $ 2.\" 3.\" Copyright (c) 2012 Microsoft Corp. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.Dd September 10, 2013 28.Dt HYPER-V 4 29.Os 30.Sh NAME 31.Nm vmbus 32.Nd Hyper-V Virtual Machine Bus (VMBus) Driver 33.Sh SYNOPSIS 34To load the driver as a 35module at boot time, place the following line in 36.Xr loader.conf 5 : 37.Bd -literal -offset indent 38vmbus_load="YES" 39.Ed 40.Sh DESCRIPTION 41The 42.Nm 43provides a high performance communication interface between 44guest and root partitions in Hyper-V. 45Hyper-V is a hypervisor-based virtualization technology from Microsoft. 46Hyper-V supports isolation in terms of a partition. 47A partition is a 48logical unit of isolation, supported by the hypervisor, in which 49operating systems execute. 50.Pp 51The Microsoft hypervisor must have at least one parent, or root, 52partition, running Windows Server operating system. 53The virtualization stack runs in the parent partition and has 54direct access to the hardware devices. 55The root partition then creates the child partitions which host 56the guest operating systems. 57.Pp 58Child partitions do not have direct access to other hardware resources 59and are presented 60a virtual view of the resources, as virtual devices (VDevs). 61Requests to the virtual devices are 62redirected either via the VMBus or the hypervisor to the devices in 63the parent partition, which handles the requests. 64.Pp 65The VMBus is a logical inter-partition communication channel. 66The parent partition hosts Virtualization Service Providers (VSPs) 67which communicate over the VMBus to handle device access requests from 68child partitions. 69Child partitions host Virtualization Service 70Consumers (VSCs) which redirect device requests to VSPs in the parent 71partition via the VMBus. 72The Hyper-V VMBus driver defines and implements 73the interface that facilitate high performance bi-directional communication 74between the VSCs and VSPs. 75All VSCs utilize the VMBus driver. 76.\".Sh SEE ALSO 77.\".Xr hv_ata_pci_disengage 4 , 78.\".Xr hv_netvsc 4 , 79.\".Xr hv_storvsc 4 , 80.\".Xr hv_utils 4 81.Sh HISTORY 82Support for 83.Nm 84first appeared in 85.Fx 10.0 86and was subsequently brought into 87.Dx 4.5 . 88The driver was developed through a joint effort between Citrix Incorporated, 89Microsoft Corporation, and Network Appliance Incorporated. 90.Sh AUTHORS 91.An -nosplit 92.Fx 93support for 94.Nm 95was first added by 96.An Microsoft BSD Integration Services Team Aq Mt bsdic@microsoft.com . 97