static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
		unsigned nr, bool has_error, u32 error_code,
	        bool has_payload, unsigned long payload, bool reinject)
{
	u32 prev_nr;
	int class1, class2;

	kvm_make_request(KVM_REQ_EVENT, vcpu);

	if (!vcpu->arch.exception.pending && !vcpu->arch.exception.injected) {
	queue:
		if (has_error && !is_protmode(vcpu))
			has_error = false;
		if (reinject) {
			/*
			 * On vmentry, vcpu->arch.exception.pending is only
			 * true if an event injection was blocked by
			 * nested_run_pending.  In that case, however,
			 * vcpu_enter_guest requests an immediate exit,
			 * and the guest shouldn't proceed far enough to
			 * need reinjection.
			 */
			WARN_ON_ONCE(vcpu->arch.exception.pending);
			vcpu->arch.exception.injected = true;
			if (WARN_ON_ONCE(has_payload)) {
				/*
				 * A reinjected event has already
				 * delivered its payload.
				 */
				has_payload = false;
				payload = 0;
			}
		} else {
			vcpu->arch.exception.pending = true;
			vcpu->arch.exception.injected = false;
		}
		vcpu->arch.exception.has_error_code = has_error;
		vcpu->arch.exception.nr = nr;
		vcpu->arch.exception.error_code = error_code;
		vcpu->arch.exception.has_payload = has_payload;
		vcpu->arch.exception.payload = payload;
		/*
		 * In guest mode, payload delivery should be deferred,
		 * so that the L1 hypervisor can intercept #PF before
		 * CR2 is modified (or intercept #DB before DR6 is
		 * modified under nVMX).  However, for ABI
		 * compatibility with KVM_GET_VCPU_EVENTS and
		 * KVM_SET_VCPU_EVENTS, we can't delay payload
		 * delivery unless userspace has enabled this
		 * functionality via the per-VM capability,
		 * KVM_CAP_EXCEPTION_PAYLOAD.
		 */
		if (!vcpu->kvm->arch.exception_payload_enabled ||
		    !is_guest_mode(vcpu))
			kvm_deliver_exception_payload(vcpu);
		return;
	}

	/* to check exception */
	prev_nr = vcpu->arch.exception.nr;
	if (prev_nr == DF_VECTOR) {
		/* triple fault -> shutdown */
		kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu);
		return;
	}
	class1 = exception_class(prev_nr);
	class2 = exception_class(nr);
	if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY)
		|| (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
		/*
		 * Generate double fault per SDM Table 5-5.  Set
		 * exception.pending = true so that the double fault
		 * can trigger a nested vmexit.
		 */
		vcpu->arch.exception.pending = true;
		vcpu->arch.exception.injected = false;
		vcpu->arch.exception.has_error_code = true;
		vcpu->arch.exception.nr = DF_VECTOR;
		vcpu->arch.exception.error_code = 0;
		vcpu->arch.exception.has_payload = false;
		vcpu->arch.exception.payload = 0;
	} else
		/* replace previous exception with a new one in a hope
		   that instruction re-execution will regenerate lost
		   exception */
		goto queue;
}
Unknown