From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35203) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aOkDn-0001mi-2Y for qemu-devel@nongnu.org; Thu, 28 Jan 2016 05:54:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aOkDm-0005Ce-0F for qemu-devel@nongnu.org; Thu, 28 Jan 2016 05:54:39 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51887) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aOkDl-0005Ca-RK for qemu-devel@nongnu.org; Thu, 28 Jan 2016 05:54:37 -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 (Postfix) with ESMTPS id 5D48E445A7 for ; Thu, 28 Jan 2016 10:54:37 +0000 (UTC) From: Igor Mammedov Date: Thu, 28 Jan 2016 11:54:24 +0100 Message-Id: <1453978470-222624-3-git-send-email-imammedo@redhat.com> In-Reply-To: <1453978470-222624-1-git-send-email-imammedo@redhat.com> References: <1453978470-222624-1-git-send-email-imammedo@redhat.com> Subject: [Qemu-devel] [PATCH v19 2/9] 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: ehabkost@redhat.com, mst@redhat.com, ghammer@redhat.com, lersek@redhat.com, lcapitulino@redhat.com From: Gal Hammer Signed-off-by: Gal Hammer Signed-off-by: Igor Mammedov Reviewed-by: Eric Blake --- docs/specs/vmgenid.txt | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 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..462d17f --- /dev/null +++ b/docs/specs/vmgenid.txt @@ -0,0 +1,36 @@ +VIRTUAL MACHINE GENERATION ID +============================= + +Copyright (C) 2016 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 PCI device with the following ACPI ID: "QEMU0003". + +The device has a "vmgenid.guid" property, which can be set using +the command line argument or the QMP interface. +For example: +QEMU -device vmgenid,id=FOO,guid="324e6eaf-d1d1-4bf6-bf41-b9bb6c91fb87" + +Or to change guid in runtime use: + qom-set "/machine/peripheral/FOO.guid" "124e6eaf-d1d1-4bf6-bf41-b9bb6c91fb87" + +According to the specification, any change to the GUID executes an +ACPI notification. The vmgenid device triggers the \_GPE._E00 handler +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. -- 1.8.3.1