On 16/11/2014 22:49, Nadav Amit wrote:
> @@ -374,13 +378,15 @@ static inline void apic_clear_irr(int vec, struct
> kvm_lapic *apic)
>
> vcpu = apic->vcpu;
>
> - apic_clear_vector(vec, apic->regs + APIC_IRR);
> - if (unlikely(kvm_apic_vid_enabled(vcpu->kvm)))
> + if (unlikely(kvm_apic_vid_enabled(vcpu->kvm))) {
> /* try to update RVI */
> + apic_clear_vector(vec, apic->regs + APIC_IRR);
> kvm_make_request(KVM_REQ_EVENT, vcpu);
> - else {
> - vec = apic_search_irr(apic);
> - apic->irr_pending = (vec != -1);
> + } else {
> + apic->irr_pending = false;
> + apic_clear_vector(vec, apic->regs + APIC_IRR);
> + if (apic_search_irr(apic) != -1)
> + apic->irr_pending = true;
> }
> }
This is even more tricky than it looks like. :)
No one can concurrently look at apic->irr_pending while it is false, in
particular apic_sync_pv_eoi_to_guest cannot enable PV EOI by mistake
just because it sees a false irr_pending. So it's okay if it is first
set to false and then to true.
I'll apply the patch tomorrow.
Paolo
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