1.\" $FreeBSD$ 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 hv_vmbus 32.Nd Hyper-V Virtual Machine Bus (VMBus) Driver 33.Sh SYNOPSIS 34To compile this driver into the kernel, place the following lines in 35the system kernel configuration file: 36.Bd -ragged -offset indent 37.Cd "device hyperv" 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_utils 4 , 77.Xr hv_netvsc 4 , 78.Xr hv_storvsc 4 , 79.Xr hv_ata_pci_disengage 4 80.Sh HISTORY 81Support for 82.Nm 83first appeared in 84.Fx 10.0 . 85The driver was developed through a joint effort between Citrix Incorporated, 86Microsoft Corporation, and Network Appliance Incorporated. 87.Sh AUTHORS 88.An -nosplit 89.Fx 90support for 91.Nm 92was first added by 93.An Microsoft BSD Integration Services Team Aq bsdic@microsoft.com . 94