RE: [Qemu-devel] [PATCH 3/9] powerpc/kvm: Enable mpic for E500 platform

[Hollis Blanchard <hollisb@us.ibm.com>]

On Fri, 2009-01-16 at 13:34 +0800, Liu Yu wrote:
> 
> > -----Original Message-----
> > From: Anthony Liguori [mailto:anthony@codemonkey.ws] 
> > Sent: Friday, January 16, 2009 5:23 AM
> > To: qemu-devel@nongnu.org
> > Cc: Liu Yu-B13201; kvm-ppc@vger.kernel.org
> > Subject: Re: [Qemu-devel] [PATCH 3/9] powerpc/kvm: Enable 
> > mpic for E500 platform
> > 
> > Liu Yu wrote:
> > > The modify is based on original author's method
> > > to switch openpic and mpic by static define,
> > > like the switch between USE_INTEL_GW80314 and USE_MPCxxx.
> > > (Although the support for intel has broken)
> > > So they can't be used at the same time.
> > >
> > > I guess it's not the correct way to do this.
> > > but I am not sure is the USE_MPC85xx and openpic are still needed?
> > >   
> > 
> > Have you tested some of the other (TCG) boards (for instance, 
> > with the 
> > debian image Aurelien recently posted)?
> > 
> 
> You mean test powerpc mac99? No.

It doesn't sound like mac99 works right now anyways, so that may not be
possible to test.

> I only modified few places to the original code. I think it won't be influenced.
> But mpic and openpic couldnot work in the same qemu binary with this patch.
> If they should both be supported, then I need to modify more.

Due to the (artificial) "ppc" vs "ppcemb" split, I'm not sure this is a
requirement.

The only issue I can see is if there are "ppc" targets (e.g. 970) that
use the same[1] MPIC as found on e500, and that is different from and
not supported by the current OpenPIC emulation.

[1] By "same" I mean "substantially similar". As I understand it,
OpenPIC and MPIC are very similar designs, but there are different
bugs/quirks to different implementations. So even if e500's MPIC isn't
*exactly* the same as 970 chipsets' MPIC, if they're close enough that
the code could be shared, it should be.

-- 
Hollis Blanchard
IBM Linux Technology Center