NAME

     hv_vmbus — Hyper-V Virtual Machine Bus (VMBus) Driver

SYNOPSIS

     To compile this driver into the kernel, place the following lines in the system kernel
     configuration file:

           device hyperv
           device pci

DESCRIPTION

     The hv_vmbus provides a high performance communication interface between guest and root
     partitions in Hyper-V.  Hyper-V is a hypervisor-based virtualization technology from
     Microsoft.  Hyper-V supports isolation in terms of a partition.  A partition is a logical
     unit of isolation, supported by the hypervisor, in which operating systems execute.

     The Microsoft hypervisor must have at least one parent, or root, partition, running Windows
     Server operating system.  The virtualization stack runs in the parent partition and has
     direct access to the hardware devices.  The root partition then creates the child partitions
     which host the guest operating systems.

     Child partitions do not have direct access to other hardware resources and are presented a
     virtual view of the resources, as virtual devices (VDevs).  Requests to the virtual devices
     are redirected either via the VMBus or the hypervisor to the devices in the parent
     partition, which handles the requests.

     The VMBus is a logical inter-partition communication channel.  The parent partition hosts
     Virtualization Service Providers (VSPs) which communicate over the VMBus to handle device
     access requests from child partitions.  Child partitions host Virtualization Service
     Consumers (VSCs) which redirect device requests to VSPs in the parent partition via the
     VMBus.  The Hyper-V VMBus driver defines and implements the interface that facilitate high
     performance bi-directional communication between the VSCs and VSPs.  All VSCs utilize the
     VMBus driver.

SEE ALSO

     hv_netvsc(4), hv_storvsc(4), hv_utils(4)

HISTORY

     Support for hv_vmbus first appeared in FreeBSD 10.0.  The driver was developed through a
     joint effort between Citrix Incorporated, Microsoft Corporation, and Network Appliance
     Incorporated.

AUTHORS

     FreeBSD support for hv_vmbus was first added by Microsoft BSD Integration Services Team
     <bsdic@microsoft.com>.