From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 29 Jun 2017 17:14:50 +0200
Subject: KVM: lapic: reorganize restart_apic_timer
Patch-mainline: v4.13-rc1
Git-commit: a749e247f745f609fd1106f1400ea063fe9b18ba
References: bsc#1077761

Move the code to cancel the hv timer into the caller, just before
it starts the hrtimer.  Check availability of the hv timer in
start_hv_timer.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Alexander Graf <agraf@suse.de>
---
 arch/x86/kvm/lapic.c |   85 ++++++++++++++++++++++++---------------------------
 arch/x86/kvm/lapic.h |    2 -
 arch/x86/kvm/x86.c   |    8 ++--
 3 files changed, 45 insertions(+), 50 deletions(-)

--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1499,17 +1499,21 @@
 
 static void cancel_hv_timer(struct kvm_lapic *apic)
 {
+	WARN_ON(!apic->lapic_timer.hv_timer_in_use);
 	preempt_disable();
 	kvm_x86_ops->cancel_hv_timer(apic->vcpu);
 	apic->lapic_timer.hv_timer_in_use = false;
 	preempt_enable();
 }
 
-static bool __start_hv_timer(struct kvm_lapic *apic)
+static bool start_hv_timer(struct kvm_lapic *apic)
 {
 	struct kvm_timer *ktimer = &apic->lapic_timer;
 	int r;
 
+	if (!kvm_x86_ops->set_hv_timer)
+		return false;
+
 	if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending))
 		return false;
 
@@ -1527,19 +1531,30 @@
 	 */
 	if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending))
 		return false;
+
+	trace_kvm_hv_timer_state(apic->vcpu->vcpu_id, true);
 	return true;
 }
 
-static bool start_hv_timer(struct kvm_lapic *apic)
+static void start_sw_timer(struct kvm_lapic *apic)
 {
-	if (!__start_hv_timer(apic)) {
-		if (apic->lapic_timer.hv_timer_in_use)
-			cancel_hv_timer(apic);
-	}
+	struct kvm_timer *ktimer = &apic->lapic_timer;
+	if (apic->lapic_timer.hv_timer_in_use)
+		cancel_hv_timer(apic);
+	if (!apic_lvtt_period(apic) && atomic_read(&ktimer->pending))
+		return;
+
+	if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic))
+		start_sw_period(apic);
+	else if (apic_lvtt_tscdeadline(apic))
+		start_sw_tscdeadline(apic);
+	trace_kvm_hv_timer_state(apic->vcpu->vcpu_id, false);
+}
 
-	trace_kvm_hv_timer_state(apic->vcpu->vcpu_id,
-			apic->lapic_timer.hv_timer_in_use);
-	return apic->lapic_timer.hv_timer_in_use;
+static void restart_apic_timer(struct kvm_lapic *apic)
+{
+	if (!start_hv_timer(apic))
+		start_sw_timer(apic);
 }
 
 void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu)
@@ -1553,19 +1568,14 @@
 
 	if (apic_lvtt_period(apic) && apic->lapic_timer.period) {
 		advance_periodic_target_expiration(apic);
-		if (!start_hv_timer(apic))
-			start_sw_period(apic);
+		restart_apic_timer(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);
-
-	start_hv_timer(apic);
+	restart_apic_timer(vcpu->arch.apic);
 }
 EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_hv_timer);
 
@@ -1574,33 +1584,28 @@
 	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_timer(apic);
+	if (apic->lapic_timer.hv_timer_in_use)
+		start_sw_timer(apic);
+}
+EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_sw_timer);
 
-	if (atomic_read(&apic->lapic_timer.pending))
-		return;
+void kvm_lapic_restart_hv_timer(struct kvm_vcpu *vcpu)
+{
+	struct kvm_lapic *apic = vcpu->arch.apic;
 
-	if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic))
-		start_sw_period(apic);
-	else if (apic_lvtt_tscdeadline(apic))
-		start_sw_tscdeadline(apic);
+	WARN_ON(!apic->lapic_timer.hv_timer_in_use);
+	restart_apic_timer(apic);
 }
-EXPORT_SYMBOL_GPL(kvm_lapic_switch_to_sw_timer);
 
 static void start_apic_timer(struct kvm_lapic *apic)
 {
 	atomic_set(&apic->lapic_timer.pending, 0);
 
-	if (apic_lvtt_period(apic) || apic_lvtt_oneshot(apic)) {
-		if (set_target_expiration(apic) &&
-			!(kvm_x86_ops->set_hv_timer && start_hv_timer(apic)))
-			start_sw_period(apic);
-	} else if (apic_lvtt_tscdeadline(apic)) {
-		if (!(kvm_x86_ops->set_hv_timer && start_hv_timer(apic)))
-			start_sw_tscdeadline(apic);
-	}
+	if ((apic_lvtt_period(apic) || apic_lvtt_oneshot(apic))
+	    && !set_target_expiration(apic))
+		return;
+
+	restart_apic_timer(apic);
 }
 
 static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val)
@@ -1831,16 +1836,6 @@
  * 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)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -87,7 +87,6 @@
 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);
 
@@ -216,4 +215,5 @@
 void kvm_lapic_switch_to_hv_timer(struct kvm_vcpu *vcpu);
 void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu);
 bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu);
+void kvm_lapic_restart_hv_timer(struct kvm_vcpu *vcpu);
 #endif
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2842,10 +2842,10 @@
 			kvm_vcpu_write_tsc_offset(vcpu, offset);
 			vcpu->arch.tsc_catchup = 1;
 		}
-		if (kvm_lapic_hv_timer_in_use(vcpu) &&
-				kvm_x86_ops->set_hv_timer(vcpu,
-					kvm_get_lapic_target_expiration_tsc(vcpu)))
-			kvm_lapic_switch_to_sw_timer(vcpu);
+
+		if (kvm_lapic_hv_timer_in_use(vcpu))
+			kvm_lapic_restart_hv_timer(vcpu);
+
 		/*
 		 * On a host with synchronized TSC, there is no need to update
 		 * kvmclock on vcpu->cpu migration