Re: Building ppc/powerpc kernel to run under QEMU.

[Rob Landley <rob@landley.net>]

On Thursday 10 May 2007 6:07 pm, Matt Sealey wrote:
> QEMU really really wants a PREP kernel, and that stuff's just not in the new
> arch/powerpc tree anymore is it?

In theory I could feed it a power mac kernel, but I'd have to create a 
partitioned hard drive image to satisfy open hackware.  A prep kernel fakes 
being a partitioned image sufficiently that I can use -kernel to boot.

> I'd love to see the device tree once QEMU's kernel has booted :D

So would I. :)

I'm told they've got that part working.  I once managed to get a powerpc 
Ubuntu ISO image to boot under qemu, I just can't _build_ a kernel that does.  
(I have no idea how to create the specially partitioned hard drive image it 
wants, and since I got 5 other architectures working without needing to do 
that, I'm looking for a way to make a prep kernel work so I won't have to.)

> I wonder.. would it be useful to have a qemu platform in arch/powerpc and
> for someone to start hacking in devices from a non-emulated point of view?
> It seems a bit of a waste in my mind to emulate a network card, serial port
> IDE interface, ADB (yick!) and a VESA graphics adapter in such 'detail' when
> it can be passed back to the emulation somehow through some kind of clever
> call interface (maybe just have the zero page of the emulation contain a
> bunch of 'ports' which are really function calls pointers..?)

Yeah, but qemu already _has_ an IDE interface, graphics card (an old western 
digital something or other), and network card working.  Once they got 'em 
working on one platform, they can plug them into a virtual PCI bus for other 
platforms.

What I wind up fighting with most when trying to get multiple platforms to 
work is firmware and bootloaders.  (All of which are insane, without 
exception so far.)  This is why I like the qemu -kernel thing, which lets me 
bypass the whole issue...

Usually.

Rob