KVM: LAPIC: introduce kvm_get_lapic_target_expiration_tsc()

Introdce kvm_get_lapic_target_expiration_tsc() to get APIC Timer target
deadline tsc.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Yunhong Jiang <yunhong.jiang@intel.com>
Signed-off-by: NWanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

arch/x86/kvm/lapic.c

@@ -1706,6 +1706,15 @@ void kvm_free_lapic(struct kvm_vcpu *vcpu)
  * LAPIC interface
  *----------------------------------------------------------------------
  */
+u64 kvm_get_lapic_target_expiration_tsc(struct kvm_vcpu *vcpu)
+{
+	struct kvm_lapic *apic = vcpu->arch.apic;
+
+	if (!lapic_in_kernel(vcpu))
+		return 0;
+
+	return apic->lapic_timer.tscdeadline;
+}
 
 u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu)
 {

arch/x86/kvm/lapic.h

@@ -85,6 +85,7 @@ int kvm_apic_get_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s);
 int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s);
 int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu);
 
+u64 kvm_get_lapic_target_expiration_tsc(struct kvm_vcpu *vcpu);
 u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu);
 void kvm_set_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu, u64 data);
 

arch/x86/kvm/x86.c

@@ -2794,7 +2794,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		}
 		if (kvm_lapic_hv_timer_in_use(vcpu) &&
 				kvm_x86_ops->set_hv_timer(vcpu,
-					kvm_get_lapic_tscdeadline_msr(vcpu)))
+					kvm_get_lapic_target_expiration_tsc(vcpu)))
 			kvm_lapic_switch_to_sw_timer(vcpu);
 		/*
 		 * On a host with synchronized TSC, there is no need to update