Re: [PATCH 1/2] KVM: x86: ioapic: Set remote_irr only after successful delivery

> 
> > Btw, currently the IRQ is set to irr_delivered for level-triggered IRQ
> > regardless of the return value of kvm_irq_delivery_to_apic():
> > 
> >         if (irqe.trig_mode == IOAPIC_EDGE_TRIG)                                
> >                 ioapic->irr_delivered |= 1 << irq;           


[...]

> Thanks, yes, I think you're right. irr_delivered has the same problem for
> edge-triggered interrupts: it is used to hide delivered edge IRQs from
> KVM_GET_IRQCHIP, but currently it is set before knowing whether delivery
> actually succeeded. If delivery fails, KVM_GET_IRQCHIP can incorrectly
> drop the pending IRR bit.

Sorry as I replied in v2, I misread the code that I thought irr_delivered is for
level-triggered IRQ too.  For edge triggered I think the hardware behaviour is
once it is triggered the IRQ is considered delivered, since it's just an "edge".

> 
> I'll send a v2 that gates both remote_irr and irr_delivered on ret > 0, and
> extend the selftest to cover the edge-triggered irr_delivered case too.

I wish I saw this reply earlier.  Again sorry for the noise.