Re: [RFC PATCH 3/5] hw/i386/acpi-build: Add ACPI PCI hot-plug methods to q35

[Igor Mammedov]

On Wed, 15 Jul 2020 08:57:51 +0200
Gerd Hoffmann <kraxel@redhat.com> wrote:

> On Mon, Jul 13, 2020 at 04:39:54PM +0200, Igor Mammedov wrote:
> > On Thu,  9 Jul 2020 00:46:13 +0200
> > Julia Suvorova <jusual@redhat.com> wrote:
> >   
> > > Implement notifications and gpe to support q35 ACPI PCI hot-plug.
> > > The addresses specified in [1] remain the same to make fewer changes.
> > > 
> > > [1] docs/spec/acpi_pci_hotplug.txt  
> > 
> > CCing Gerd his opinion on reusing piix4 IO port range for q35  

[...]

> While being at it:  Shouldn't we reserve these port ranges somehow?
> Using an acpi device for example, simliar to fw_cfg?  The guest OS
> should better know there is something at those ports ...

we do it at ACPI level in DSDT, look for comment
/* reserve PCIHP resources */

It should make Windows trip over in case of another range overlap with
reserved ports. (linux kernel is more tolerant and may silently ignore
or print a warning) 

> take care,
>   Gerd
>