From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45073) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YLCTT-0003lr-Dc for qemu-devel@nongnu.org; Tue, 10 Feb 2015 10:11:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YLCTQ-0002Sp-3k for qemu-devel@nongnu.org; Tue, 10 Feb 2015 10:11:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55585) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YLCTP-0002Sc-Qy for qemu-devel@nongnu.org; Tue, 10 Feb 2015 10:11:36 -0500 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t1AFBZIB006800 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Tue, 10 Feb 2015 10:11:35 -0500 From: Gal Hammer Date: Tue, 10 Feb 2015 17:02:44 +0200 Message-Id: <1423580566-15498-2-git-send-email-ghammer@redhat.com> In-Reply-To: <1423580566-15498-1-git-send-email-ghammer@redhat.com> References: <1423580566-15498-1-git-send-email-ghammer@redhat.com> Subject: [Qemu-devel] [PATCH V12 1/3] docs: vm generation id device's description List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Gal Hammer Signed-off-by: Gal Hammer --- docs/specs/vmgenid.txt | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 docs/specs/vmgenid.txt diff --git a/docs/specs/vmgenid.txt b/docs/specs/vmgenid.txt new file mode 100644 index 0000000..656d598 --- /dev/null +++ b/docs/specs/vmgenid.txt @@ -0,0 +1,38 @@ +VIRTUAL MACHINE GENERATION ID +============================= + +Copyright (C) 2014 Red Hat, Inc. + +This work is licensed under the terms of the GNU GPL, version 2 or later. +See the COPYING file in the top-level directory. + +=== + +The VM generation ID (vmgenid) device is an emulated device which +exposes a 128-bit, cryptographically random, integer value identifier. +This allows management applications (e.g. libvirt) to notify the guest +operating system when the virtual machine is executed with a different +configuration (e.g. snapshot execution or creation from a template). + +This is specified on the web at: http://go.microsoft.com/fwlink/?LinkId=260709 + +--- + +The vmgenid device is a sysbus device with the following ACPI ID: +"QEMU0002". + +The device adds a "vmgenid.uuid" property, which can be modified using +the -global command line argument or the QMP interface. + +The device uses a fixed memory resource: 0xfedf0000-0xfedf0003. The +guest is expected to write the physical address of the GUID's buffer +to that memory resource. This allows the device to modify the GUID if +requested by the management application. Current device's implementation +supports a 32-bit address. + +According to the specification, any change to the GUID executes an +ACPI notification. The vmgenid device triggers the GPE._E00 which +executes the ACPI Notify operation. + +Although not specified in Microsoft's document, it is assumed that the +device is expected to use the little-endian system. -- 2.1.0