Re: [Qemu-devel] [RFC/RFT PATCH v2 0/3] KVM: Introduce KVM_MEM_UNCACHED

[Peter Maydell]

On 14 May 2015 at 13:28, Paolo Bonzini <address@hidden> 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