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