Re: [Qemu-devel] [PATCH] sparc32 machine specific maximums

["Blue Swirl" <blauwirbel@gmail.com>]

On 12/5/07, Robert Reif <reif@earthlink.net> wrote:
> Blue Swirl wrote:
>
> >On 12/4/07, Robert Reif <reif@earthlink.net> wrote:
> >
> >
> >>I would be surprised if an SMP kernel actually worked on a multi CPU SS5.
> >>
> >>
> >
> >Prepare for a surprise:
> >
> >
> >
> That's interesting because the fact that it works shows how inaccurate
> the emulation is.

This wonder is not possible because of the any inaccuracies, it's
possible because there is an Open Firmware abstraction layer between
the OS and hardware. If more CPUs are available, Linux just starts
them using the OF interface. Linux can't check whether the system is
physically capable of containing more CPUs, it can merely check that
the platform is Sun4m, which is fully SMP capable.

> Now could you please really surprise me by booting Solaris 2.5 using a
> real sun openprom image ;-)

The interface between OF and hardware is not completely documented
(SMP) and Qemu is by design not completely suitable to emulate
everything that the real prom wants, like caches, performance counters
or test/debug modes. Therefore I'm more interested in booting Solaris
using OpenBIOS image.  While the interface between OF and Solaris is
documented, the assumptions used by Solaris aren't.

But I'd be happy to fix bugs or implement the missing details to
either Qemu or OpenBIOS that help Solaris boot.