Re: [Qemu-devel] [PATCH v8 4/8] ACPI: Add Virtual Machine Generation ID support

[Ben Warren]

> On Feb 17, 2017, at 2:43 AM, Igor Mammedov <address@hidden> wrote:
> 
> On Thu, 16 Feb 2017 15:15:36 -0800
> address@hidden wrote:
> 
>> From: Ben Warren <address@hidden>
>> 
>> This implements the VM Generation ID feature by passing a 128-bit
>> GUID to the guest via a fw_cfg blob.
>> Any time the GUID changes, an ACPI notify event is sent to the guest
>> 
>> The user interface is a simple device with one parameter:
>> - guid (string, must be "auto" or in UUID format
>>   xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)
> I've given it some testing with WS2012R2 and v4 patches for Seabios,
> 
> Windows is able to read initial GUID allocation and writeback
> seems to work somehow:
> 
> (qemu) info vm-generation-id 
> c109c09b-0e8b-42d5-9b33-8409c9dcd16c
> 
> vmgenid client in Windows reads it as 2 following 64bit integers:
> 42d50e8bc109c09b:6cd1dcc90984339b
> 
> However update path/restore from snapshot doesn't
> here is as I've tested it:
> 
> qemu-system-x86_64 -device vmgenid,id=testvgid,guid=auto -monitor stdio
> (qemu) info vm-generation-id 
> c109c09b-0e8b-42d5-9b33-8409c9dcd16c
> (qemu) stop
> (qemu) migrate "exec:gzip -c > STATEFILE.gz" 
> (qemu) quit
> 
> qemu-system-x86_64 -device vmgenid,id=testvgid,guid=auto -monitor stdio
> -incoming "exec: gzip -c -d STATEFILE.gz"
> (qemu) info vm-generation-id 
> 28b587fa-991b-4267-80d7-9cf28b746fe9
> 
> guest
> 1. doesn't get GPE notification that it must receive
> 2. vmgenid client in Windows reads the same value
>      42d50e8bc109c09b:6cd1dcc90984339b
> 
Strange, this was working for me, but with a slightly different test method:
I use virsh save/restore
While I do later testing with Windows, during development I use a Linux kernel 
module I wrote that keeps track of GUID and notifications.  I’m happy to share 
this with you if interested.

I’ll dig into this morning.

—Ben
<snip>

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