KVM: Avoid double interrupt injection with vapic
After an interrupt injection, the PPR changes, and we have to reflect that
into the vapic. This causes a KVM_REQ_EVENT to be set, which causes the
whole interrupt injection routine to be run again (harmlessly).
Optimize by only setting KVM_REQ_EVENT if the ppr was lowered; otherwise
there is no chance that a new injection is needed.
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 413f897..93cf9d0 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -277,7 +277,8 @@
if (old_ppr != ppr) {
apic_set_reg(apic, APIC_PROCPRI, ppr);
- kvm_make_request(KVM_REQ_EVENT, apic->vcpu);
+ if (ppr < old_ppr)
+ kvm_make_request(KVM_REQ_EVENT, apic->vcpu);
}
}