1.\" $NetBSD: xenbus.4,v 1.3 2014/03/18 18:20:39 riastradh Exp $ 2.\" 3.\" Copyright (c) 2011 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Jean-Yves Migeon <jym@NetBSD.org>. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.Dd January 8, 2011 31.Dt XENBUS 4 xen 32.Os 33.Sh NAME 34.Nm xenbus 35.Nd Xen bus abstraction for paravirtualized drivers 36.Sh SYNOPSIS 37.Cd "xenbus* at hypervisor?" 38.Sh DESCRIPTION 39The 40.Nm 41interface offers an abstraction layer used for communications 42between domains. 43.Nm 44is mainly used by split paravirtualized drivers, so backend and frontend 45devices can exchange configuration information, properties, and 46statistics. 47.Pp 48.Nm 49is not used for data transfer (network frames, blocks, 50PCI commands, ...). This functionality is implemented by each paravirtualized 51driver independently, typically via shared memory pages and an event 52channel that serves as a virtual interrupt, for signaling. 53.Pp 54The 55.Nm 56abstraction offers guests the possibility to read and write information 57directly from and to XenStore, a centralized database accessible to 58all domains. 59For this reason, it also has an event channel associated to it, so that 60domains can post messages to the XenStore facility. 61.Sh DIAGNOSTICS 62.Bl -diag 63.It "xenbus0: using event channel %d" 64The event channel associated to the 65.Nm 66interface, for communication with the XenStore database. 67.El 68.Sh SEE ALSO 69.Xr pciback 4 , 70.Xr xbd 4 , 71.Xr xbdback 4 , 72.Xr xennet 4 , 73.Xr xpci 4 , 74.Xr xvif 4 75.Sh HISTORY 76The 77.Nm 78driver first appeared in 79.Nx 3.0 . 80.Sh AUTHORS 81.An -nosplit 82The 83.Nm 84driver was written by 85.An Manuel Bouyer Aq Mt bouyer@NetBSD.org . 86