Re: [SeaBIOS] [Qemu-devel] [PATCH 2/3] Add a new PCI region type to supports 64 bit ranges

[Alexey Korolev]

> > @@ -69,6 +72,8 @@ static enum pci_region_type pci_addr_to_type(u32 addr)
> >   {
> >       if (addr&  PCI_BASE_ADDRESS_SPACE_IO)
> >           return PCI_REGION_TYPE_IO;
> > if (addr&  PCI_BASE_ADDRESS_MEM_TYPE_64)
> >    return PCI_REGION_TYPE_PREFMEM_64;
>
> This seems dangerous - a 64bit bar can be non-prefetchable - getting
> this wrong could cause random (hard to debug) crashes.

Just out of curiosity - how this could happen? Having 64bit
non-prefetchable BAR implies that the device is not behind
any bridge (as bridges describe 64bit ranges for prefetchable
memory only). Is it possible on nowadays systems?