Re: [Qemu-devel] [SeaBIOS] [PATCH] acpi: hide 64-bit PCI hole for Windows XP

[Michael S. Tsirkin]

On Wed, Aug 07, 2013 at 09:29:39AM +0200, Gerd Hoffmann wrote:
> We'll need some way for seabios to fill in the pci window information
> into the qemu-provided tables.  Easiest way to do that would be to
> extend the COMMAND_ADD_POINTER bios linker script command.

This idea certainly has an advantage: the two patch-sets
(to control PCI hole from QEMU, and to pass ACPI tables
 from QEMU) would become independent.

One difficulty would be coming up with a sane interface
that's not tied to specific AML code: unlike table
pointers which have a specific fixed-width format, we are talking
about generic AML code here.  Patching that works (we do it today with
the ACPI_EXTRACT code) but requires that you code AML in a specific way,
for example, number encoding is variable-length so we pad values ahead
of the time making sure the AML encoding is large enough to hold the
maximum possible value.

Also, in the past both Anthony and Kevin indicated preference to
the pci-info solution that we have in QEMU today.

-- 
MST