On Fri, Mar 21, 2014 at 10:27:59AM +0100, Paolo Bonzini wrote: > This ensures that IRR bits are set in the KVM_GET_IRQCHIP result only if > the interrupt is still sitting in the IOAPIC. After the next patches, it > avoids spurious reinjection of the interrupt when KVM_SET_IRQCHIP is > called. > > Reviewed-by: Alex Williamson <alex.williamson@xxxxxxxxxx> > Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > --- > virt/kvm/ioapic.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c > index 0b4914147b9d..25e16a6898ed 100644 > --- a/virt/kvm/ioapic.c > +++ b/virt/kvm/ioapic.c > @@ -288,6 +288,9 @@ static int ioapic_service(struct kvm_ioapic *ioapic, int irq, bool line_status) > irqe.level = 1; > irqe.shorthand = 0; > > + if (irqe.trig_mode == IOAPIC_EDGE_TRIG) > + ioapic->irr &= ~(1 << irq); > + Now, every call to ioapic_service() for an edge interrupt clears the IRR bit immediately (assuming the mask is unset). If the IRR bit is immediately zero on delivery, why won't this break the edge detection logic on kvm_ioapic_set_irq()? Am I missing some additional detail? In other words, won't this cause spurious interrupts if kvm_ioapic_set_irq(..., true) is called twice? -- Eduardo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
