Re: [PATCH 4/4][RFC] kvm: eoi_eventfd

[Alex Williamson <alex.williamson@redhat.com>]

On Sun, 2012-06-24 at 15:56 +0300, Avi Kivity wrote:
> On 06/23/2012 01:16 AM, Alex Williamson wrote:
> > I think we're probably also going to need something like this.
> > When running in non-accelerated qemu, we're going to have to
> > create some kind of EOI notifier for drivers.  VFIO can make
> > additional improvements when running on KVM so it will probably
> > make use of the KVM_IRQFD_LEVEL_EOI interface, but we don't
> > want to have a generic EOI notifier in qemu that just stops
> > working when kvm-ioapic is enabled.
> 
> Why?

Hmm, I must be missing something or not describing it correctly, because
it seems obvious.  If we create a dependency in qemu of needing to know
when an eoi occurs and notifier a driver and have no way to fulfill that
dependency when running on kvm... that'd be bad, right?  I don't want to
assume that every consumer of such an interface would prefer to make use
of an irqfd.  Not sure if that answers your question though.  Thanks,

Alex