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

[Paolo Bonzini]

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.