Re: [Qemu-ppc] [PATCH] mac99: Bring memory layout closer to real hardware

[Mark Cave-Ayland]

On 14/04/14 08:21, Alexander Graf wrote:

> > I agree with adjusting the mac99 model instead of starting from
> > scratch not only because it's less work but also because there's not
> > much point in keeping a machine called mac99 that does not match any
> > real Mac. I'll send my current patch with minimal changes to make the
> > memory layout better match what's seen on PowerMac3,1.
>
> I can't apply that without changing OpenBIOS as well. And OpenBIOS
> doesn't get the memory layout from the machine, it only gets an
> identifier that says "I'm machine numer X, use me".
>
> So we would have to add a new machine type in fw_cfg for this machine,
> as otherwise we would render newer OpenBIOS incompatible with older QEMU
> at which point we can as well just call the whole thing a new machine.

There is actually precedent for making simultaneous OpenBIOS and QEMU 
changes; there have been a couple of times where the fw_cfg interface 
has changed in the past and Blue has done simultaneous commits in order 
to facilitate the update. Given that OpenBIOS doesn't really have a 
stable branch as such, I'd be okay with another coordinated update 
during a quiet OpenBIOS spell in the QEMU 2.1 development period.


ATB,

Mark.