Re: [PATCHv0 RFC] kvm: irqfd support for level interrupts

[Avi Kivity <avi@redhat.com>]

On 07/26/2009 07:22 PM, Michael S. Tsirkin wrote:
> Here's an untested patch with partial support for level triggered
> interrupts in irqfd. What this patch has: support for clearing interrupt
> on ack. What this patch does not have: support signalling eventfd on ack
> so that userspace can take action and e.g. reenable interrupt.
>
> Gleb, Marcelo, I'd like your input on the approach taken wrt locking.
> Does it look sane?
>
> Avi, how's the interface? I intend to also add an eventfd probably in
> the padding in the irqfd struct.
>    

What about the state-capable eventfd?  Seems much more natural for this.

>
>   static struct workqueue_struct *irqfd_cleanup_wq;
> @@ -63,10 +65,15 @@ irqfd_inject(struct work_struct *work)
>
>   	mutex_lock(&kvm->irq_lock);
>   	kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1);
> -	kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0);
> +	if (!irqfd->is_level)
> +		kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0);
>    

e.g. inject the eventfd->state as the irq level.

-- 
error compiling committee.c: too many arguments to function