Merge "KVM: x86: support using the vmx preemption timer for tsc deadline timer"

1 files changed, 72 insertions, 1 deletions

diff --git a/kernel/arch/x86/kvm/lapic.c b/kernel/arch/x86/kvm/lapic.c
index 1e1e7eb8e..701f91234 100644
--- a/kernel/arch/x86/kvm/lapic.c
+++ b/kernel/arch/x86/kvm/lapic.c
@@ -1288,6 +1288,68 @@ static void start_sw_tscdeadline(struct kvm_lapic *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);
+
+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));
+	kvm_x86_ops->cancel_hv_timer(vcpu);
+	apic->lapic_timer.hv_timer_in_use = false;
+	apic_timer_expired(apic);
+}
+EXPORT_SYMBOL_GPL(kvm_lapic_expired_hv_timer);
+
+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) &&
+	    !atomic_read(&apic->lapic_timer.pending)) {
+		u64 tscdeadline = apic->lapic_timer.tscdeadline;
+
+		if (!kvm_x86_ops->set_hv_timer(vcpu, tscdeadline)) {
+			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)) {
+				apic->lapic_timer.hv_timer_in_use = false;
+				kvm_x86_ops->cancel_hv_timer(apic->vcpu);
+			}
+		}
+		trace_kvm_hv_timer_state(vcpu->vcpu_id,
+				apic->lapic_timer.hv_timer_in_use);
+	}
+}
+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;
+
+	kvm_x86_ops->cancel_hv_timer(vcpu);
+	apic->lapic_timer.hv_timer_in_use = false;
+
+	if (atomic_read(&apic->lapic_timer.pending))
+		return;
+
+	start_sw_tscdeadline(apic);
+}
+EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_sw_timer);
+
 static void start_apic_timer(struct kvm_lapic *apic)
 {
 	ktime_t now;
@@ -1334,7 +1396,16 @@ static void start_apic_timer(struct kvm_lapic *apic)
 			   ktime_to_ns(ktime_add_ns(now,
 					apic->lapic_timer.period)));
 	} else if (apic_lvtt_tscdeadline(apic)) {
-		start_sw_tscdeadline(apic);
+		/* lapic timer in tsc deadline mode */
+		u64 tscdeadline = apic->lapic_timer.tscdeadline;
+
+		if (kvm_x86_ops->set_hv_timer &&
+		    !kvm_x86_ops->set_hv_timer(apic->vcpu, tscdeadline)) {
+			apic->lapic_timer.hv_timer_in_use = true;
+			trace_kvm_hv_timer_state(apic->vcpu->vcpu_id,
+					apic->lapic_timer.hv_timer_in_use);
+		} else
+			start_sw_tscdeadline(apic);
 	}
 }