Re: [Qemu-devel] [Qemu-ppc] [PATCH] mac99: Bring memory layout closer to real hardware

[Alexander Graf <agraf@suse.de>]

On 20.03.14 11:16, BALATON Zoltan wrote:
> On Sat, 15 Mar 2014, BALATON Zoltan wrote:
>> Try to better match the memory map of a PowerMac3,1 model by moving
>> the pci-cfg mappings to where they are on a real machine. Also add the
>> VGA card after the macio to let the latter be mapped from 0x80000000 to
>> match hardware. (On real hardware the graphics card is on a different
>> bus but we don't seem to model that yet.)
>>
>> Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
>> ---
>>
>> This patch is intended to bring memory layout closer to what's seen in
>> these dumps:
>>
>> http://nandra.segv.jp/NetBSD/G4.dump-device-tree.txt
>> http://raveland.org/ports/eeprom.txt
>> http://mail-index.netbsd.org/port-macppc/2007/10/24/0000.html
>> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=604134
>>
>> It makes MorphOS a little happier and not print alerts when creating
>> its memory map but not happy enough to not crash later.
>
> I'm not so sure about this patch either by now. I've come across some 
> logs that show that these MorphOS alerts can happen on real hardware 
> too and are probably not related to the crash but it needs more 
> debugging and experimenting. If anyone has any ideas how to converge 
> QEMU's model to what's seen in the dumps above please let me know.

Yeah, I'd rather hold back on this until we fix a real bug.

The problem with the mac99 target in QEMU is that it doesn't match any 
real machine out there. It's essentially a hack good enough to get a 
good amount of Linux and Mac OS X working, but I'm sure if you don't 
look at the device tree for device creation you'll blow up :).

The "real" fix would be to create a new machine model that models 
*exactly* a real system from scratch.


Alex