Re: [RFC][PATCH 3/3] In DM_LOWEST, only deliver interrupts to vcpus with enabled LAPIC's

Gleb Natapov
2010-06-09T11:20:29Z

On Wed, Jun 09, 2010 at 02:08:31PM +0300, Avi Kivity wrote:
> On 06/09/2010 02:01 PM, Gleb Natapov wrote:
> >On Tue, Jun 08, 2010 at 01:55:03PM -0400, Chris Lalancette wrote:
> >>Otherwise we might try to deliver a timer interrupt to a cpu that
> >>can't possibly handle it.
> >>
> >>Signed-off-by: Chris Lalancette<clalance@redhat.com>
> >>---
> >> virt/kvm/irq_comm.c | 2 +-
> >> 1 files changed, 1 insertions(+), 1 deletions(-)
> >>
> >>diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
> >>index 52f412f..06cf61e 100644
> >>--- a/virt/kvm/irq_comm.c
> >>+++ b/virt/kvm/irq_comm.c
> >>@@ -100,7 +100,7 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
> >> if (r< 0)
> >> r = 0;
> >> r += kvm_apic_set_irq(vcpu, irq);
> >>- } else {
> >>+ } else if (kvm_lapic_enabled(vcpu)) {
> >> if (!lowest)
> >> lowest = vcpu;
> >> else if (kvm_apic_compare_prio(vcpu, lowest)< 0)
> >Shouldn't we check kvm_lapic_enabled(vcpu) at the beginning of the loop?
> >Something like:
> > if (!kvm_apic_present(vcpu) || !kvm_lapic_enabled(vcpu))
> > continue;
> >
>
> The apic still accepts some interrupts even if disabled, so this
> needs to be very conditional.
>
What kind of interrupt and can they be delivered in DM_LOWEST mode?

--
Gleb.