On 2012-08-13 21:31, Anthony Liguori wrote: > Jan Kiszka <jan.kiszka@xxxxxxxxxxx> writes: > >> On 2012-08-13 15:58, Avi Kivity wrote: >>> On 08/13/2012 04:27 PM, Anthony Liguori wrote: >>> >>>> Thanks for pushing this forward! Hopefully this will finally kill off >>>> qemu-kvm.git for good. >>> >>> No, it won't. vfio requires a 3.6 kernel, which we cannot assume anyone >>> has. We'll need the original device assignment code side-by-side. >> >> ...which is on my to-do list for 1.3. > > Is there a deprecation plan for the old device assignment code? > > I'm not really against the idea of requiring a new kernel for new > features. > > From a Fedora/OpenSUSE point of view, would supporting old kernels be a > requirement to stop shipping qemu-kvm.git over qemu.git? > > Since distros ship new kernels and new userspaces, I don't think distros > would care so I'm not sure who we're trying to support old kernels for. We are supporting KVM down to 2.6.3x, if not 2.6.2x. Also, device assignment is a new feature for upstream, but not for the masses of KVM users of QEMU (due to qemu-kvm and corresponding libvirt support). I think it will take some more kernel releases to have all feature there that allows performance-wise equivalent device assignment via VFIO. And it can even be helpful to cross-check issues of VFIO in the field. Except for some self-contained helper functions in the KVM layer, classic device assignment will be as isolated as VFIO. So I don't think we would take any noteworthy burden to maintain it as long as the kernel supports this interface. Can't comment on the other questions. Jan
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