KVM: Add some helper functions for Posted-Interrupts

This patch adds some helper functions to manipulate the
Posted-Interrupts Descriptor.
Signed-off-by: NFeng Wu <feng.wu@intel.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NAlex Williamson <alex.williamson@redhat.com>
[Make the new functions inline. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx.c

@@ -443,6 +443,8 @@ struct nested_vmx {
 };
 
 #define POSTED_INTR_ON  0
+#define POSTED_INTR_SN  1
+
 /* Posted-Interrupt Descriptor */
 struct pi_desc {
 	u32 pir[8];     /* Posted interrupt requested */
@@ -483,6 +485,30 @@ static int pi_test_and_set_pir(int vector, struct pi_desc *pi_desc)
 	return test_and_set_bit(vector, (unsigned long *)pi_desc->pir);
 }
 
+static inline void pi_clear_sn(struct pi_desc *pi_desc)
+{
+	return clear_bit(POSTED_INTR_SN,
+			(unsigned long *)&pi_desc->control);
+}
+
+static inline void pi_set_sn(struct pi_desc *pi_desc)
+{
+	return set_bit(POSTED_INTR_SN,
+			(unsigned long *)&pi_desc->control);
+}
+
+static inline int pi_test_on(struct pi_desc *pi_desc)
+{
+	return test_bit(POSTED_INTR_ON,
+			(unsigned long *)&pi_desc->control);
+}
+
+static inline int pi_test_sn(struct pi_desc *pi_desc)
+{
+	return test_bit(POSTED_INTR_SN,
+			(unsigned long *)&pi_desc->control);
+}
+
 struct vcpu_vmx {
 	struct kvm_vcpu       vcpu;
 	unsigned long         host_rsp;