Re: [PATCH-for-5.0 1/2] hw/acpi/piix4: Add 'system-hotplug-support' property

[Marcelo Tosatti]

On Mon, Mar 23, 2020 at 09:05:06AM +0100, Paolo Bonzini wrote:
> On 22/03/20 17:27, Philippe Mathieu-Daudé wrote:
> >>>
> >> That 'ugly' is typically used within QEMU to deal with such things
> >> probably due to its low complexity.
> > 
> > OK. Can you point me to the documentation for this feature? I can find
> > reference of GPE in the ICH9, but I can't find where this IO address on
> > the PIIX4 comes from:
> > 
> > #define GPE_BASE 0xafe0
> 
> It's made up.  The implementation is placed in PIIX4_PM because it is
> referenced by the ACPI tables.  Real hardware would probably place this
> in the ACPI embedded controller or in the BMC.
> 
> Paolo

Yes, there was nothing at 0xafe0 at the time ACPI support was written.