From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Vrabel <david.vrabel@citrix.com>
Subject: Re: [PATCH 5/6] libxl: allow a generation ID to be
 specified at domain creation
Date: Tue, 10 Jun 2014 14:41:51 +0100
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To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: xen-devel@lists.xenproject.org, Ian Jackson <ian.jackson@eu.citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>
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On 10/06/14 14:37, Ian Campbell wrote:
> On Tue, 2014-06-10 at 13:35 +0100, David Vrabel wrote:
>> On 10/06/14 12:01, Ian Campbell wrote:
>>> On Tue, 2014-06-03 at 14:15 +0100, David Vrabel wrote:
>>>> Toolstacks may specify a VM generation ID using the
>>>> u.hvm.generation_id field into libxl_domain_build_info structure, when
>>>> creating a domain.
>>>>
>>>> The toolstack is responsible for providing the correct generation ID
>>>> according to the Microsoft specification (e.g., generating new random
>>>> ones as appropriate when restoring).
>>>
>>> Any reason not to make the libxl interface a (def)bool and have libxl
>>> generate a suitable ID internally? Does anything ever care about the
>>> specific UUID?
>>
>> Other toolstacks (like xapi) have a better idea of the life-cycle of a
>> VM than xl does and thus need only use a new ID for snapshots -- they
>> can retain the same ID if the domain is just rebooted/migrated.
> 
> They should set the field to false then and libxl won't regenerate it.

They still need an interface to specify the ID.

I don't see any value in adding a use_random_genid field just to avoid a
single libxl_uuid_generate() call in the toolstack.

David