KVM: VMX: Fix check guest state validity if a guest is in VM86 mode

If guest vcpu is in VM86 mode the vcpu state should be checked as if in
real mode.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/vmx.c

@@ -3605,7 +3605,7 @@ static bool guest_state_valid(struct kvm_vcpu *vcpu)
 		return true;
 
 	/* real mode guest state checks */
-	if (!is_protmode(vcpu)) {
+	if (!is_protmode(vcpu) || (vmx_get_rflags(vcpu) & X86_EFLAGS_VM)) {
 		if (!rmode_segment_valid(vcpu, VCPU_SREG_CS))
 			return false;
 		if (!rmode_segment_valid(vcpu, VCPU_SREG_SS))