Re: Emulated macppc with qemu

[Michael <macallan%netbsd.org@localhost>]

Hello,

On Mon, 5 Apr 2021 12:00:15 +0100
Mark Cave-Ayland <mark.cave-ayland%ilande.co.uk@localhost> wrote:

> On 04/04/2021 20:58, Havard Eidnes wrote:

> > There appears to be something finicky about the amount of memory:
> > 1G fails with a trap early on, 3G fails as described in
> > 
> >    https://bugs.launchpad.net/bugs/1922391
> > 
> > quite a bit into the installation, but with 2G I've managed to
> > install and it appears to run stably as well.  

This caught my eye a bit late, but...
How is >2GB RAM supposed to work on even an emulated 32bit macppc?
The address space is divided up by hardware into 0x0 - 0x7fffffff for
RAM, and above that lives PCI space, various onboard devices and
firmware ROMs. If you map extra RAM into this range NetBSD will need
adjustments since we BAT-map most of this space 1:1.
That said, it shouldn't be hard to get this working, just have to pay
more attention when entering BAT mappings, and the RAM counting code
may ignore areas above 0x80000000.

have fun
Michael