Re: graphics card pci passthrough success report

[Gerd Hoffmann <kraxel@redhat.com>]

  Hi,

> - Apply the patches at the end of this mail to kvm and SeaBIOS to
>   allow for more BAR space under 4G.  (The relevant BARs on the
>   graphics cards _are_ 64 bit BARs, but kvm seemed to turn those
>   into 32 bit BARs in the guest.)

Which qemu/seabios versions have you used?

qemu-1.2 (+ bundled seabios) should handle that just fine without
patching.  There is no fixed I/O window any more, all memory space above
lowmem is available for pci, i.e. if you give 2G to your guest
everything above 0x80000000.

And if there isn't enougth address space below 4G (if you assign lot of
memory to your guest so qemu keeps only the 0xe0000000 - 0xffffffff
window free) seabios should try to map 64bit bars above 4G.

> - Apply the hacky patch at the end of this mail to SeaBIOS to
>   always skip initialising the Radeon's option ROMs, or the VM
>   would hang inside the Radeon option ROM if you boot the VM
>   without the default cirrus video.

A better way to handle that would probably be to add an pci passthrough
config option to not expose the rom to the guest.

Any clue *why* the rom doesn't run?

cheers,
  Gerd