On 16/10/17 19:38, Benjamin Herrenschmidt wrote: > On Mon, 2017-10-16 at 18:36 +1100, Alexey Kardashevskiy wrote: >> >> 1. Allow msix mapping to the userspace (to address non-64k-aligned msix bar) >> >> 2. Allow write combining in vfio for the userspace (kvm guest is kinda >> special and may simply ignore mapping flags in some configs but PPC radix >> guests still rely on this) > > Why ? The "G" bit is entirely under control of the guest afaik. Yes, for hash guests. I am not sure sure about radix, Paul pointed me to the code in KVM which uses the VFIO's mapping VMA. > This > would only affect qemu itself. It's still useful for things like dpdk > using vfio. Correct, this is useful regardless KVM. >> 3. what callback and where needs to be added to inform HV/PR KVM about VFIO >> group, like IOMMUMR::add_vfio_group() proposal or something. > > Can you elaborate a bit ? I haven't followed this. David knows :) -- Alexey
