KVM_APIC_SIPI
set_bit(KVM_APIC_SIPI, &apic->pending_events);
clear_bit(KVM_APIC_SIPI, &apic->pending_events);
if (test_and_clear_bit(KVM_APIC_SIPI, &apic->pending_events)) {
test_bit(KVM_APIC_SIPI, &apic->pending_events)) {
clear_bit(KVM_APIC_SIPI, &apic->pending_events);
set_bit(KVM_APIC_SIPI, &vcpu->arch.apic->pending_events);