On 14 May 2015 at 13:28, Paolo Bonzini <pbonz...@redhat.com> wrote: > Well, PCI BARs are generally MMIO resources, and hence should not be cached. > > As an optimization, OS drivers can mark them as cacheable or > write-combining or something like that, but in general it's a safe > default to leave them uncached---one would think.
Isn't this handled by the OS mapping them in the 'prefetchable' MMIO window rather than the 'non-prefetchable' one? (QEMU's generic-PCIe device doesn't yet support the prefetchable window.) -- PMM
