Re: [Qemu-devel] [PATCH V2] virtio: Fix no interrupt when not creating msi controller

[Michael S. Tsirkin]

On Tue, Jan 24, 2017 at 04:50:44PM +0100, Paolo Bonzini wrote:
> 
> 
> On 24/01/2017 16:05, Michael S. Tsirkin wrote:
> >>
> >> So we have four cases:
> >>
> >> - assign with emulated irqfd + ISR
> >> - assign with emulated irqfd
> >> - assign with irqfd
> >> - deassign
> >>
> >> Currently we don't distinguish the first two, so (which I don't like)
> >> Shannon's patch ends up setting ISR twice.
> > 
> > I don't see this yet - where is it set twice?
> 
> Once in virtio_notify_irqfd, once in virtio_queue_guest_notifier_read.
> 
> Unfortunately, for virtio-blk + MSI + KVM + old Windows drivers we need
> the one in virtio_notify_irqfd.  For virtio-net + vhost + INTx we need
> the one in virtio_queue_guest_notifier_read.

Well in MSI mode virtio_queue_guest_notifier_read so we only do this
once, right? I need to check INTx mode - does virtio_notify_irqfd
get called then?

-- 
MST