Re: [Qemu-devel] PPC emulation on Qemu

[J. Mayer]

On Mon, 2004-02-16 at 05:08, Benjamin Herrenschmidt wrote:
> > Well, I did look a lot MOL code but didn't use it for now. I won't reuse
> > MOL OF code, because I don't want to have hardcoded stuffs, but
> > something that acts really like the open-firmware and will be able to
> > boot any OS, just like Bochs BIOS does for PC's.
> 
> Latest "devel" tree from Samuel started integrating OpenBIOS in MOL
> (that is a full OF implementation).

OpenBios would be great, but it seems to be far from running. I got
something nearly running, in host environment. But if OpenBios gets
close to a full real Bios, I'd be glad to use it !

> > But emulated hardware from MOL will be helpfull someday. For now, I want
> > to concentrate on booting Linux for Prep hardware. Because it's mainly a
> > PC with a PPC CPU, it's a real good target to debug CPU emulation
> > problems without taking care of emulated hardware.
> 
> It's also the shitties PPC hardware out there ;) Instane memory map

Yes, I know it's nearly a virtual platform, but, has I have some tests
kernels that should run on it, it makes debug simpler. But I agree this
emulation is just a step to a real complete hardware emulation...

> > Then, I want a standard and nowedays PPC platform, not only Macs, nea
> > OpenPPC standard.
> 
> What is OpenPPC standard ? So far, the most "standard" PPCs are
> PowerMacs ;) 

Well, G4 Macs are close to OpenPPC standard, which is an open platform
which has been described by IBM. I like it has a reference because it's
nearly Macs and because AIX, MacOS (X I suppose) and Linux should be
able to run on it.

> > So I did an open-pic emulation, ... MOL code will be helpfull
> > to emulate some Mac platforms, but as it says, it seems to me that's
> > it's too much Mac & MacOS dedicated to help until I got full stable
> > basics.
> 
> It can run the linux kernel as well. It's oriented toward emulation
> speed though. It has this nice "OSI" calls mecanism that allows
> cross call from within the emulated environment to the emulator
> linux-side. That along with host-side drivers using these calls
> allows significant perfs. improvements for things like disk
> access, sound, etc... but that's all optional.

Yes I know it can run Linux, but what I wanted to point is that (if I'm
not wrong) it's not able to run any OS (ie AIX or pegasos or, why not
(?), BeOS or AmigaOS) like a real machine would.
I agree that MOL exactly intend to do this, and does it well, but I
think qemu should really emulate the whole execution environment...

Does the OSI calls mechanism needs patched OS and/or firmware ?

-- 
J. Mayer <address@hidden>
Never organized