Re: [Qemu-devel] [PATCH 2/2] q35: add cpu hotplug support

[Gerd Hoffmann]

On Fr, 2013-10-04 at 15:20 +0200, Igor Mammedov wrote:
> On Wed, 21 Aug 2013 13:01:32 +0200
> Gerd Hoffmann <address@hidden> wrote:
> 
> >   Hi,
> > 
> > > +#define ICH9_PROC_BASE 0xaf00
> > > +#define ICH9_PROC_LEN 32
> > 
> > No, please don't.  It makes it impossible to assign the 0xa000 -> 0xafff
> > I/O port window to a PCI bridge.  Please lets stop occupy random io
> > ports above 0x1000 and burn I/O address space that way.
> I'm curios why 0x1000 is any better than 0xa000, it still would be random
> port occupation. Is there any guideline which ports could be used and which
> shouldn't?

0x1000 doesn't by us anything.  *below* 0x1000 gives us one more pci io
window which we can assign to a pci bridge then.

> Could we safely move PIIX CPU hotplug 0xaf00-0xaf20 range below 0x1000?

I'd love to, but unfortunaly it isn't that easy as the address is
hard-coded in the DSDT.

Once mst acpi generation patches are in it would be a bit simpler, but
we would still break compatibility with seabios versions not fetching
the acpi tables from qemu.

cheers,
  Gerd