KVM: x86: No error-code on real-mode exceptions

Real-mode exceptions do not deliver error code. As can be seen in Intel SDM
volume 2, real-mode exceptions do not have parentheses, which indicate
error-code.  To avoid significant changes of the code, the error code is
"removed" during exception queueing.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -353,6 +353,8 @@ static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
 
 	if (!vcpu->arch.exception.pending) {
 	queue:
+		if (has_error && !is_protmode(vcpu))
+			has_error = false;
 		vcpu->arch.exception.pending = true;
 		vcpu->arch.exception.has_error_code = has_error;
 		vcpu->arch.exception.nr = nr;