+static void start_sw_tscdeadline(struct kvm_lapic *apic)
+{
+ u64 guest_tsc, tscdeadline = apic->lapic_timer.tscdeadline;
+ u64 ns = 0;
+ ktime_t expire;
+ struct kvm_vcpu *vcpu = apic->vcpu;
+ unsigned long this_tsc_khz = vcpu->arch.virtual_tsc_khz;
+ unsigned long flags;
+ ktime_t now;
+
+ if (unlikely(!tscdeadline || !this_tsc_khz))
+ return;
+
+ local_irq_save(flags);
+
+ now = apic->lapic_timer.timer.base->get_time();
+ guest_tsc = kvm_read_l1_tsc(vcpu, rdtsc());
+ if (likely(tscdeadline > guest_tsc)) {
+ ns = (tscdeadline - guest_tsc) * 1000000ULL;
+ do_div(ns, this_tsc_khz);
+ expire = ktime_add_ns(now, ns);
+ expire = ktime_sub_ns(expire, lapic_timer_advance_ns);
+ hrtimer_start(&apic->lapic_timer.timer,
+ expire, HRTIMER_MODE_ABS_PINNED);
+ } else
+ apic_timer_expired(apic);
+
+ local_irq_restore(flags);
+}
+
+bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu)
+{
+ return vcpu->arch.apic->lapic_timer.hv_timer_in_use;
+}
+EXPORT_SYMBOL_GPL(kvm_lapic_hv_timer_in_use);
+
+static void cancel_hv_tscdeadline(struct kvm_lapic *apic)
+{
+ kvm_x86_ops->cancel_hv_timer(apic->vcpu);
+ apic->lapic_timer.hv_timer_in_use = false;
+}
+
+void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu)
+{
+ struct kvm_lapic *apic = vcpu->arch.apic;
+
+ WARN_ON(!apic->lapic_timer.hv_timer_in_use);
+ WARN_ON(swait_active(&vcpu->wq));
+ cancel_hv_tscdeadline(apic);
+ apic_timer_expired(apic);
+}
+EXPORT_SYMBOL_GPL(kvm_lapic_expired_hv_timer);
+
+static bool start_hv_tscdeadline(struct kvm_lapic *apic)
+{
+ u64 tscdeadline = apic->lapic_timer.tscdeadline;
+
+ if (atomic_read(&apic->lapic_timer.pending) ||
+ kvm_x86_ops->set_hv_timer(apic->vcpu, tscdeadline)) {
+ if (apic->lapic_timer.hv_timer_in_use)
+ cancel_hv_tscdeadline(apic);
+ } else {
+ apic->lapic_timer.hv_timer_in_use = true;
+ hrtimer_cancel(&apic->lapic_timer.timer);
+
+ /* In case the sw timer triggered in the window */
+ if (atomic_read(&apic->lapic_timer.pending))
+ cancel_hv_tscdeadline(apic);
+ }
+ trace_kvm_hv_timer_state(apic->vcpu->vcpu_id,
+ apic->lapic_timer.hv_timer_in_use);
+ return apic->lapic_timer.hv_timer_in_use;
+}
+
+void kvm_lapic_switch_to_hv_timer(struct kvm_vcpu *vcpu)
+{
+ struct kvm_lapic *apic = vcpu->arch.apic;
+
+ WARN_ON(apic->lapic_timer.hv_timer_in_use);
+
+ if (apic_lvtt_tscdeadline(apic))
+ start_hv_tscdeadline(apic);
+}
+EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_hv_timer);
+
+void kvm_lapic_switch_to_sw_timer(struct kvm_vcpu *vcpu)
+{
+ struct kvm_lapic *apic = vcpu->arch.apic;
+
+ /* Possibly the TSC deadline timer is not enabled yet */
+ if (!apic->lapic_timer.hv_timer_in_use)
+ return;
+
+ cancel_hv_tscdeadline(apic);
+
+ if (atomic_read(&apic->lapic_timer.pending))
+ return;
+
+ start_sw_tscdeadline(apic);
+}
+EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_sw_timer);
+