Re: [Qemu-devel] [PATCHv4 0/5] Clean up compatibility mode handling

[David Gibson <david@gibson.dropbear.id.au>]

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On Wed, May 31, 2017 at 10:58:57AM +0200, Greg Kurz wrote:
> On Wed, 31 May 2017 12:57:48 +1000
> David Gibson <david@gibson.dropbear.id.au> wrote:
> > [...]
> > > All old non-pseries machine types already complain when started with
> > > a POWER7 or newer CPU. Providing the extra error message looks weird:
> > > 
> > > qemu-system-ppc64 -machine ppce500 \
> > >                   -cpu POWER7,compat=power6
> > > qemu-system-ppc64: CPU 'compat' property is deprecated and has no effect;
> > >  use max-cpu-compat machine property instead
> > > MMU model 983043 not supported by this machine.
> > > 
> > > but I guess it's better than crashing. :)  
> > 
> > Well, sure POWER7 doesn't make sense for an e500 machine for other
> > reasons.  But POWER7 or POWER8 _would_ make sense for powernv, where
> > compat= doesn't.
> > 
> 
> The powernv machine type doesn't even support CPU features at all:
> 
>     chip_typename = g_strdup_printf(TYPE_PNV_CHIP "-%s", machine->cpu_model);
>     if (!object_class_by_name(chip_typename)) {
>         error_report("invalid CPU model '%s' for %s machine",
>                      machine->cpu_model, MACHINE_GET_CLASS(machine)->name);
>         exit(1);
>     }

Ah, well, that's another bug, but not one that's in scope for this
series.



-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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