Re: [Xen-devel] [BUG] pci: mixed allocation pf and non-pf PCI MEM BAR (OVMF crash)

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 31.03.19 at 10:11, <martin@xxxxxxxxx> wrote:
> There is problem in PCI device allocation algorithm (pci_setup()).
> Algorithm allocates PCI BAR sorted by size and this allows
> mixed allocation of prefetchable and non-prefetchable PCI MEM BAR.
> This leads to wrong config of PCI root port (see "Type 1 Configuration 
> Space Registers (Root Ports)").
> 
> Tested with version xen 4.11.1 + "export 
> OVMF_UPSTREAM_REVISION=ef529e6ab7c31290a33045bb1f1837447cc0eb56"
> (embeded commit OVMF does not work (crashed even in Win10.iso and 
> uncompilable with newer gcc)).
> 
> Attached also testing patch.

I agree the problem wants addressing, but I'm afraid the patch is
incomplete: Afaict it won't work if there is a non-prefetchable BAR
larger than the smallest prefetchable one, due to the necessary
extra padding that would need inserting between the two.

Also the patch lack your S-o-b and has a couple of style issues
(hard tab used, indentation, lack of blanks inside if(), unnecessary
double use of PCI_BASE_ADDRESS_MEM_PREFETCH).

As to its description - do you perhaps mean "interleaved" instead
of "fragmented" and "not allowed" instead of "not supported"?

Jan



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