On Thu, Nov 14, 2013 at 08:58:18AM +0100, Gerd Hoffmann
wrote:> Hi,
>
> > > > OVMF
> > > > should just use whatever it gets.
> > >
> > > What would OVMF use them for?
> > >
> >
> > To reserve range for MMIO holes, so that later PCI resource allocation
> > protocol can only use those ranges.
>
> I'm still not convinced you need that in the first place.
>
> When booting seabios @ xen it is not needed. pci ressource allocation
> is handled by hvmloader. apci tables (and the ressources declared
> therein) are handled by hvmloader. seabios doesn't touch the pci bars
> and passes through the apci tables -> guest os is happy.
>
> So why ovmf should be different? IMHO it should operate like seabios
> and NOT do pci ressource allocation when running on xen. Ressources are
> already handled already by hvmloader. Doing it again is (a) pointless
> and (b) creates problems like the one we are discussion right now.
>
Agreed. But the protocol to allocate PCI resources seems to be mandatory
according to UEFI spec [0].
--- page 16
The following protocols are mandatory if the system supports PCI devices
or slots:
• EFI_PCI_HOST_BRIDGE_RESOURCE_ALLOCATION_PROTOCOL
• EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL
--
I'm more than happy to disable that allocation protocol if there's a
way.
Wei.
[0]
http://www.intel.com/content/dam/doc/reference-guide/efi-pci-host-bridge-allocation-protocol-specification.pdf
> cheers,
> Gerd
>
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