Re: [Qemu-devel] [PATCH 5/5] spapr: drop DIV_ROUND_UP() from xics_max_server_number()

["Daniel P. Berrangé" <berrange@redhat.com>]

On Thu, Feb 15, 2018 at 05:08:57PM +0100, Greg Kurz wrote:
> On Thu, 15 Feb 2018 15:08:18 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > On Wed, Feb 14, 2018 at 08:41:03PM +0100, Greg Kurz wrote:
> 
> <snip>
> 
> > > 
> > > It breaks migration of pre-2.7 machine types with unusual CPU topologies,
> > > but I guess this is an acceptable trade-off.  
> > 
> > No, not really.  Weird topologies are still allowed on old machine
> > types for backwards compatibility, and we shouldn't break that.  I
> > like the idea of consolidating this calculation, but we can't do it by
> > just breaking the older machines (at least not until they're formally
> > deprecated).
> > 
> 
> Heh, I had put this patch at the end because I was expecting you might
> nack it :)
> 
> Per curiosity, when/how do we decide that an older machine type may be
> formally deprecated ?

For versioned machine types we decided that we'd keep them around upstream
for as long as they were needed by a downstream vendor, *provided* that
downstream vendor is contributing to QEMU in order to mitigate the maint
burden it would entail. 

Regards,
Daniel
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