Re: [Qemu-devel] Versioned machine types for ARM/non-x86 ? (Was Re: [PATCH v4 0/2] ARM: add 'virt' platform)

[Daniel P. Berrange]

On Mon, Aug 05, 2013 at 02:02:54PM +0100, Peter Maydell wrote:
> On 5 August 2013 13:49, Daniel P. Berrange <address@hidden> wrote:
> > On x86, we've long had versioned machine names, so that we can
> > make changes in future QEMU releases without breaking guest ABI
> > compatibility. AFAICT, the problem has basically been ignored
> > on non-x86 platforms in QEMU.
> 
> Yes; this is deliberate on the basis that starting to do this
> is accepting a huge pile of maintenance workload (ie checking
> for things which change, keeping around a pile of old version
> machine models, retaining migration compatibility between
> old and new versions). Which isn't to say I'm against it
> but it means I'm not doing it until the pushback from users
> that it's necessary is pretty strong.
> 
> > Given the increased interest in
> > ARM in particular, should we use the addition of this new 'virt'
> > machine type, as an opportunity to introduce versioning for
> > ARM too. eg make this machine be called 'virt-1.0.6' and then
> > have 'virt' simply be an alias that points to the most recent
> > version.
> 
> I'm not convinced we're at the point where we need to do this
> yet.

Ok, fair enough. Something to consider in the future then.

Daniel
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