Re: [Qemu-devel] [edk2] [edk2 PATCH 0/1] OvmfPkg: grab ACPI tables from QEMU

[Gerd Hoffmann]

  Hi,

> > > btw: q35 has a fixed 1G window, max low ram addr is 0xb000000, the
> > > remaining address space (0xb0000000 -> 0xc0000000) is used for
> > > mmconfig.
> 
> Is it really fixed? My understanding is it's programmed by firmware,
> you can put mmconfig whereever you want.

Not really fixed, but it is a most useful configuration.  You can place
large bars (up to 512M) @ 0xc0000000 then, and you have a single region
for your bars which makes management easy.  If you place the mmconfig
somewhere else it only gets more complicated.

cheers,
  Gerd