KVM: x86: Fix posted interrupt with CONFIG_SMP=n

->send_IPI_mask is not defined on UP.

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c84f0cb..a05cca6 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3946,10 +3946,12 @@
 
 	r = pi_test_and_set_on(&vmx->pi_desc);
 	kvm_make_request(KVM_REQ_EVENT, vcpu);
+#ifdef CONFIG_SMP
 	if (!r && (vcpu->mode == IN_GUEST_MODE))
 		apic->send_IPI_mask(get_cpu_mask(vcpu->cpu),
 				POSTED_INTR_VECTOR);
 	else
+#endif
 		kvm_vcpu_kick(vcpu);
 }