KVM: LAPIC: Extract adaptive tune timer advancement logic

Extract adaptive tune timer advancement logic to a single function.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
[Rename new function. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/lapic.c

@@ -1501,27 +1501,13 @@ static inline void __wait_lapic_expire(struct kvm_vcpu *vcpu, u64 guest_cycles)
 	}
 }
 
-void wait_lapic_expire(struct kvm_vcpu *vcpu)
+static inline void adjust_lapic_timer_advance(struct kvm_vcpu *vcpu,
+					      u64 guest_tsc, u64 tsc_deadline)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
 	u32 timer_advance_ns = apic->lapic_timer.timer_advance_ns;
-	u64 guest_tsc, tsc_deadline, ns;
-
-	if (apic->lapic_timer.expired_tscdeadline == 0)
-		return;
-
-	if (!lapic_timer_int_injected(vcpu))
-		return;
+	u64 ns;
 
-	tsc_deadline = apic->lapic_timer.expired_tscdeadline;
-	apic->lapic_timer.expired_tscdeadline = 0;
-	guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());
-	trace_kvm_wait_lapic_expire(vcpu->vcpu_id, guest_tsc - tsc_deadline);
-
-	if (guest_tsc < tsc_deadline)
-		__wait_lapic_expire(vcpu, tsc_deadline - guest_tsc);
-
-	if (!apic->lapic_timer.timer_advance_adjust_done) {
 	/* too early */
 	if (guest_tsc < tsc_deadline) {
 		ns = (tsc_deadline - guest_tsc) * 1000000ULL;
@@ -1535,6 +1521,7 @@ void wait_lapic_expire(struct kvm_vcpu *vcpu)
 		timer_advance_ns += min((u32)ns,
 			timer_advance_ns / LAPIC_TIMER_ADVANCE_ADJUST_STEP);
 	}
+
 	if (abs(guest_tsc - tsc_deadline) < LAPIC_TIMER_ADVANCE_ADJUST_DONE)
 		apic->lapic_timer.timer_advance_adjust_done = true;
 	if (unlikely(timer_advance_ns > 5000)) {
@@ -1542,7 +1529,29 @@ void wait_lapic_expire(struct kvm_vcpu *vcpu)
 		apic->lapic_timer.timer_advance_adjust_done = true;
 	}
 	apic->lapic_timer.timer_advance_ns = timer_advance_ns;
-	}
+}
+
+void wait_lapic_expire(struct kvm_vcpu *vcpu)
+{
+	struct kvm_lapic *apic = vcpu->arch.apic;
+	u64 guest_tsc, tsc_deadline;
+
+	if (apic->lapic_timer.expired_tscdeadline == 0)
+		return;
+
+	if (!lapic_timer_int_injected(vcpu))
+		return;
+
+	tsc_deadline = apic->lapic_timer.expired_tscdeadline;
+	apic->lapic_timer.expired_tscdeadline = 0;
+	guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());
+	trace_kvm_wait_lapic_expire(vcpu->vcpu_id, guest_tsc - tsc_deadline);
+
+	if (guest_tsc < tsc_deadline)
+		__wait_lapic_expire(vcpu, tsc_deadline - guest_tsc);
+
+	if (unlikely(!apic->lapic_timer.timer_advance_adjust_done))
+		adjust_lapic_timer_advance(vcpu, guest_tsc, tsc_deadline);
 }
 
 static void start_sw_tscdeadline(struct kvm_lapic *apic)