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[Qemu-devel] [PATCH v2 1/6] docs: vm generation id device's description

From: ben
Subject: [Qemu-devel] [PATCH v2 1/6] docs: vm generation id device's description
Date: Mon, 16 Jan 2017 11:20:53 -0800

From: Ben Warren <address@hidden>

Signed-off-by: Ben Warren <address@hidden>
Cc: Gal Hammer <address@hidden>
 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..afc1717
--- /dev/null
+++ b/docs/specs/vmgenid.txt
@@ -0,0 +1,38 @@
+Copyright (C) 2016 Red Hat, Inc.
+Copyright (C) 2016 Skyport Systems, 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 ACPI ID "QEMU_Gen_Counter_V1".
+The device has one properties, which can be set using the command line
+argument or the QMP interface:
+ guid - sets the value of the GUID
+For example:
+QEMU  -device vmgenid,guid="324e6eaf-d1d1-4bf6-bf41-b9bb6c91fb87"
+Or to change guid in runtime use:
+ set-vm-generation-id 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.

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