[SeaBIOS] Graphics card pass-through working with two pass pci-initialization

[Gerd Hoffmann]

   Hi,

> As Jan points out though, is a dynamic PCI region really needed?
> Those that need a large PCI region are also likely to need a large
> amount of memory.  Maybe the space for PCI should just be increased.

Just changing it will not work as it will break live migration.

I think one option is to keep the piix-based pc as-is, with the address 
space above 0xe0000000 being available for PCI, and make the room larger 
for the upcoming q35-based pc, say starting at 0xc0000000.  That will 
give almost 1G address space.  256 MB are used by pci mmconfig though.

The other option is to make it configurable, which in turn requires a 
dynamic PCI region.

cheers,
   Gerd