Re: [Qemu-devel] [PATCH] q35: Remove old machine versions

[Markus Armbruster]

John Snow <address@hidden> writes:

> On 08/19/2015 02:55 AM, Dr. David Alan Gilbert wrote:
>> * Eduardo Habkost (address@hidden) wrote:
>>> Migration with q35 was not possible before commit
>>> 04329029a8c539eb5f75dcb6d8b016f0c53a031a, because q35 unconditionally 
>>> creates
>>> an ich9-ahci device, that was marked as unmigratable. So all q35 machines
>>> before pc-q35-2.4 were unmigratable, and there's no point in keeping
>>> compatibility code for them.
>>>
>>> Remove all old pc-q35 machine classes and keep only pc-q35-2.4.
>> 
>> But doesn't that mean that anyone who has a machine configured with one
>> of those machine types will suddenly find it wont start?
>> 
>> Dave
>> 
>
> To some extent, all versions of this board prior to 2.4 should be
> considered unsupported and we should discourage their use anyway.
>
> If you really want, I suppose we could just alias them to 2.4 ...

I'd very much prefer an honest "won't start" over a silent change of the
machine type.

If we really want to bend over backwards for existing uses of these
machine types, we could make them error out with "use pc-q35-2.5
instead".  Since I don't think they exist outside testing, I wouldn't
bother.