Re: [PATCH v2 0/3] KVM: x86: KVM_MEM_PCI_HOLE memory

From: Gerd Hoffmann
Date: Fri Sep 18 2020 - 04:49:25 EST


> I see a similar ~8k PCI hole reads with a -kernel boot w/ OVMF. All but 60
> of those are from pcibios_fixup_peer_bridges(), and all are from the kernel.

pcibios_fixup_peer_bridges() looks at pcibios_last_bus, and that in turn
seems to be set according to the mmconfig size (in

So, maybe we just need to declare a smaller mmconfig window in the acpi
tables, depending on the number of pci busses actually used ...

> If all of the above is true, this can be handled by adding "pci=lastbus=0"

... so we don't need manual quirks like this?

take care,