Add ACPI based PCI hotplug library with bridge hotplug
support.
Design
- each bus gets assigned "bsel" property.
- ACPI code writes this number
to a new BNUM register, then uses existing
UP/DOWN registers to probe slot status;
to eject, write number to BNUM register,
then slot into existing EJ.
The interface is actually backwards-compatible with
existing PIIX4 ACPI (though not migration compatible).
This is split out from PIIX4 codebase so we can
reuse it for Q35 as well.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Michael S. Tsirkin