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>.