Re: [Xen-devel] [PATCH v2 1/3] OvmfPkg/XenSupport: remove usage of prefetchable PCI host bridge aperture

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Tue, Apr 09, 2019 at 04:12:38AM +0100, Igor Druzhinin wrote:
> This aperture doesn't exist in QEMU-XEN and hvmloader places BARs
> in arbitrary order disregarding prefetchable bit. This makes
> prefetchable and non-prefetchable BARs to follow each other that's
> quite likely with PCI passthrough devices. In that case, the existing
> code, that tries to work out aperture boundaries by reading hvmloader
> BAR placement, will report a bogus prefetchable aperture which overlaps
> with the regular one. It will eventually trigger an assertion in
> DXE PCI initialization code.
> 
> Do the same thing as OVMF on QEMU-KVM and pass a non-existing aperture
> there. It's not necessary to pass additional allocation flags as we set
> ResourceAssigned flag on the root bridge which means they will be ignored.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Igor Druzhinin <igor.druzhinin@xxxxxxxxxx>
> ---
> Changes in v2:
> * remove usage of prefetchable aperture entirely
> * explained rationale for the change in the description
> ---

Reviewed-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>

Thanks,

-- 
Anthony PERARD

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