Re: [Qemu-devel] [PATCH 2/2] Route IOAPIC interrupts via ISA bus

[Gerd Hoffmann]

On 08/27/09 10:18, Jamie Lokier wrote:
> Gleb Natapov wrote:
> > On Thu, Aug 27, 2009 at 09:40:06AM +0200, Gerd Hoffmann wrote:
> > >             Or does it mean we must emulate a more recent chipset?
> > That too will work.
>
>
> Note that if you change the chipset, it'll break some existing Windows VMs.

I think we would rather *add* a new machine type with a new chipset, not 
*replace* the piix3.  IIRC someone is already working on emulation 
something more recent (ICH9?) to get some modern stuff, so that will 
probably get us some more ioapic lines.

> I had this problem when porting a Windows Server 2003 VM from Virtual
> PC to QEMU: Virtual PC emulates a PIIX4, while QEMU provides a PIIX3
> (even though there's a PIIX4 in the source code, it's not used for PC
> emulation).  The ported image would not boot because of the change of
> chipset, until I patched the registry to accomodate the change.

Any hints where do dig in the registy?  I have a dead notebook with xp 
(disk still ok), trying to boot the disk image in kvm, and of course it 
doesn't work due to the hardware being different.  Googleing the STOP 
code printed on the blue screen hinted that xp fails to access the hard 
drive ...

It is a 5-year old intel laptop, so it probably is something like moving 
from ICH6 to PIIX3 ...

thanks,
  Gerd