Re: [Qemu-devel] 64-bit MMIO aperture expansion

[Laszlo Ersek]

On 09/21/18 19:20, Michael S. Tsirkin wrote:
> On Fri, Sep 21, 2018 at 06:01:30PM +0300, Marcel Apfelbaum wrote:
>> On 09/20/2018 05:49 PM, Laszlo Ersek wrote:

>>> Now, there's another complication, obviously -- machine type compat. In
>>> commit 9fa99d2519cb, we added the "pci_hole64_fix" compat property. I
>>> assume the additional fix I'm proposing requires another compat
>>> property?
>>
>> We have to, is a guest visible change. I really don't like these compat
>> properties, but I don't see a way around it.
> 
> Well does it only affect ACPI? Or other stuff? ACPI changes
> are mostly safe without need for compat things.

My understanding is that it affects ACPI only:

(1) q35_host_get_pci_hole64_end() is only referenced in the code when it
is set as a getter for the PCI_HOST_PROP_PCI_HOLE64_END property, in
q35_host_initfn() [hw/pci-host/q35.c].

(2) i440fx_pcihost_get_pci_hole64_end() is only referenced in the code
when it is set as a getter for the same PCI_HOST_PROP_PCI_HOLE64_END
property, in i440fx_pcihost_initfn() [hw/pci-host/piix.c].

(3) The PCI_HOST_PROP_PCI_HOLE64_END property is only fetched in
acpi_get_pci_holes() [hw/i386/acpi-build.c].

(4) acpi_get_pci_holes() is only called in acpi_build()
[hw/i386/acpi-build.c].

(5) The resultant "pci_hole64" structure is passed to build_dsdt() only.

Thanks
Laszlo