Re: [RFC PATCH] kvm: Extend irqfd to support level interrupts

["Michael S. Tsirkin" <mst@redhat.com>]

On Sat, Jun 16, 2012 at 10:34:39AM -0600, Alex Williamson wrote:
> I'm looking for opinions on this approach.  For vfio device assignment
> we minimally need a way to get EOIs from the in-kernel irqchip out to
> userspace.  Getting that out via an eventfd would allow us to bounce
> all level interrupts out to userspace, where we would de-assert the
> device interrupt in qemu and unmask the physical device.  Ideally we
> could deassert the interrupt in KVM, which allows us to send the EOI
> directly to vfio.  To do that, we need to use a new IRQ source ID so
> the guest sees the logical OR of qemu requested state and external
> device state.

Given that yopu want to involve userspace anyway, why insist on irqfd
for this?  You can simply use KVM_IRQ_LINE_STATUS from qemu, no?

-- 
MST