[patch 1/8] KVM: timer interface unification

[Marcelo Tosatti <mtosatti@redhat.com>]

[-- Attachment #1: kvm-timer-abstract --]
[-- Type: text/plain, Size: 16572 bytes --]

Hide details of timer emulation behind an interface, and unify
the hrtimer based implementation.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm-new/arch/x86/kvm/i8254.c
===================================================================
--- kvm-new.orig/arch/x86/kvm/i8254.c
+++ kvm-new/arch/x86/kvm/i8254.c
@@ -113,7 +113,7 @@ static s64 __kpit_elapsed(struct kvm *kv
 	 * itself with the initial count and continues counting
 	 * from there.
 	 */
-	remaining = hrtimer_expires_remaining(&ps->pit_timer.timer);
+	remaining = kvm_timer_remaining(&ps->pit_timer);
 	elapsed = ps->pit_timer.period - ktime_to_ns(remaining);
 	elapsed = mod_64(elapsed, ps->pit_timer.period);
 
@@ -229,7 +229,7 @@ int pit_has_pending_timer(struct kvm_vcp
 	struct kvm_pit *pit = vcpu->kvm->arch.vpit;
 
 	if (pit && kvm_vcpu_is_bsp(vcpu) && pit->pit_state.irq_ack)
-		return atomic_read(&pit->pit_state.pit_timer.pending);
+		return kvm_timer_has_pending(&pit->pit_state.pit_timer);
 	return 0;
 }
 
@@ -238,42 +238,17 @@ static void kvm_pit_ack_irq(struct kvm_i
 	struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 						 irq_ack_notifier);
 	spin_lock(&ps->inject_lock);
-	if (atomic_dec_return(&ps->pit_timer.pending) < 0)
-		atomic_inc(&ps->pit_timer.pending);
+	kvm_timer_ack(&ps->pit_timer);
 	ps->irq_ack = 1;
 	spin_unlock(&ps->inject_lock);
 }
 
-void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
-{
-	struct kvm_pit *pit = vcpu->kvm->arch.vpit;
-	struct hrtimer *timer;
-
-	if (!kvm_vcpu_is_bsp(vcpu) || !pit)
-		return;
-
-	timer = &pit->pit_state.pit_timer.timer;
-	if (hrtimer_cancel(timer))
-		hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
-}
-
 static void destroy_pit_timer(struct kvm_timer *pt)
 {
 	pr_debug("pit: execute del timer!\n");
-	hrtimer_cancel(&pt->timer);
+	kvm_timer_cancel(pt);
 }
 
-static bool kpit_is_periodic(struct kvm_timer *ktimer)
-{
-	struct kvm_kpit_state *ps = container_of(ktimer, struct kvm_kpit_state,
-						 pit_timer);
-	return ps->is_periodic;
-}
-
-static struct kvm_timer_ops kpit_ops = {
-	.is_periodic = kpit_is_periodic,
-};
-
 static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
 {
 	struct kvm_timer *pt = &ps->pit_timer;
@@ -284,20 +259,10 @@ static void create_pit_timer(struct kvm_
 	pr_debug("pit: create pit timer, interval is %llu nsec\n", interval);
 
 	/* TODO The new value only affected after the retriggered */
-	hrtimer_cancel(&pt->timer);
-	pt->period = interval;
-	ps->is_periodic = is_period;
-
-	pt->timer.function = kvm_timer_fn;
-	pt->t_ops = &kpit_ops;
-	pt->kvm = ps->pit->kvm;
-	pt->vcpu = pt->kvm->bsp_vcpu;
+	kvm_timer_cancel(pt);
 
-	atomic_set(&pt->pending, 0);
 	ps->irq_ack = 1;
-
-	hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
-		      HRTIMER_MODE_ABS);
+	kvm_timer_start(pt, interval, is_period);
 }
 
 static void pit_load_count(struct kvm *kvm, int channel, u32 val)
@@ -545,7 +510,7 @@ static int speaker_ioport_read(struct kv
 	return 0;
 }
 
-void kvm_pit_reset(struct kvm_pit *pit)
+static void kvm_pit_reset(struct kvm_pit *pit)
 {
 	int i;
 	struct kvm_kpit_channel_state *c;
@@ -559,7 +524,7 @@ void kvm_pit_reset(struct kvm_pit *pit)
 	}
 	mutex_unlock(&pit->pit_state.lock);
 
-	atomic_set(&pit->pit_state.pit_timer.pending, 0);
+	kvm_timer_reset(&pit->pit_state.pit_timer);
 	pit->pit_state.irq_ack = 1;
 }
 
@@ -568,7 +533,7 @@ static void pit_mask_notifer(struct kvm_
 	struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 
 	if (!mask) {
-		atomic_set(&pit->pit_state.pit_timer.pending, 0);
+		kvm_timer_reset(&pit->pit_state.pit_timer);
 		pit->pit_state.irq_ack = 1;
 	}
 }
@@ -608,8 +573,8 @@ struct kvm_pit *kvm_create_pit(struct kv
 
 	pit_state = &pit->pit_state;
 	pit_state->pit = pit;
-	hrtimer_init(&pit_state->pit_timer.timer,
-		     CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	kvm_timer_init(kvm, &pit_state->pit_timer);
+
 	pit_state->irq_ack_notifier.gsi = 0;
 	pit_state->irq_ack_notifier.irq_acked = kvm_pit_ack_irq;
 	kvm_register_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
@@ -634,14 +599,11 @@ struct kvm_pit *kvm_create_pit(struct kv
 
 void kvm_free_pit(struct kvm *kvm)
 {
-	struct hrtimer *timer;
-
 	if (kvm->arch.vpit) {
+		kvm_timer_cancel(&kvm->arch.vpit->pit_state.pit_timer);
 		kvm_unregister_irq_mask_notifier(kvm, 0,
 					       &kvm->arch.vpit->mask_notifier);
 		mutex_lock(&kvm->arch.vpit->pit_state.lock);
-		timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
-		hrtimer_cancel(timer);
 		kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
 		mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 		kfree(kvm->arch.vpit);
@@ -686,7 +648,7 @@ void kvm_inject_pit_timer_irqs(struct kv
 		 * last one has been acked.
 		 */
 		spin_lock(&ps->inject_lock);
-		if (atomic_read(&ps->pit_timer.pending) && ps->irq_ack) {
+		if (kvm_timer_has_pending(&ps->pit_timer) && ps->irq_ack) {
 			ps->irq_ack = 0;
 			inject = 1;
 		}
Index: kvm-new/arch/x86/kvm/kvm_timer.h
===================================================================
--- kvm-new.orig/arch/x86/kvm/kvm_timer.h
+++ kvm-new/arch/x86/kvm/kvm_timer.h
@@ -1,18 +1,25 @@
 
 struct kvm_timer {
 	struct hrtimer timer;
-	s64 period; 				/* unit: ns */
-	atomic_t pending;			/* accumulated triggered timers */
+	s64 period; 			/* unit: ns */
+	atomic_t pending;		/* accumulated triggered timers */
 	bool reinject;
-	struct kvm_timer_ops *t_ops;
+	bool periodic;
 	struct kvm *kvm;
 	struct kvm_vcpu *vcpu;
 };
 
-struct kvm_timer_ops {
-        bool (*is_periodic)(struct kvm_timer *);
-};
+void kvm_timer_init(struct kvm *kvm, struct kvm_timer *ktimer);
+void kvm_timer_start(struct kvm_timer *ktimer, u64 interval, bool periodic);
+void kvm_timer_cancel(struct kvm_timer *ktimer);
+void kvm_timer_vcpu_bind(struct kvm_timer *ktimer, struct kvm_vcpu *vcpu);
+
+int kvm_timer_has_pending(struct kvm_timer *ktimer);
+void kvm_timer_ack(struct kvm_timer *ktimer);
+void kvm_timer_reset(struct kvm_timer *ktimer);
+
+void kvm_migrate_timer(struct kvm_timer *ktimer);
 
 
-enum hrtimer_restart kvm_timer_fn(struct hrtimer *data);
+ktime_t kvm_timer_remaining(struct kvm_timer *ktimer);
 
Index: kvm-new/arch/x86/kvm/lapic.c
===================================================================
--- kvm-new.orig/arch/x86/kvm/lapic.c
+++ kvm-new/arch/x86/kvm/lapic.c
@@ -485,7 +485,7 @@ static u32 apic_get_tmcct(struct kvm_lap
 	if (apic_get_reg(apic, APIC_TMICT) == 0)
 		return 0;
 
-	remaining = hrtimer_expires_remaining(&apic->lapic_timer.timer);
+	remaining = kvm_timer_remaining(&apic->lapic_timer);
 	if (ktime_to_ns(remaining) < 0)
 		remaining = ktime_set(0, 0);
 
@@ -601,28 +601,13 @@ static void update_divide_count(struct k
 
 static void start_apic_timer(struct kvm_lapic *apic)
 {
-	ktime_t now = apic->lapic_timer.timer.base->get_time();
-
-	apic->lapic_timer.period = apic_get_reg(apic, APIC_TMICT) *
+	u64 period = apic_get_reg(apic, APIC_TMICT) *
 		    APIC_BUS_CYCLE_NS * apic->divide_count;
-	atomic_set(&apic->lapic_timer.pending, 0);
 
-	if (!apic->lapic_timer.period)
+	if (!period)
 		return;
 
-	hrtimer_start(&apic->lapic_timer.timer,
-		      ktime_add_ns(now, apic->lapic_timer.period),
-		      HRTIMER_MODE_ABS);
-
-	apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
-			   PRIx64 ", "
-			   "timer initial count 0x%x, period %lldns, "
-			   "expire @ 0x%016" PRIx64 ".\n", __func__,
-			   APIC_BUS_CYCLE_NS, ktime_to_ns(now),
-			   apic_get_reg(apic, APIC_TMICT),
-			   apic->lapic_timer.period,
-			   ktime_to_ns(ktime_add_ns(now,
-					apic->lapic_timer.period)));
+	kvm_timer_start(&apic->lapic_timer, period, apic_lvtt_period(apic));
 }
 
 static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val)
@@ -706,8 +691,6 @@ static int apic_mmio_write(struct kvm_io
 				apic_set_reg(apic, APIC_LVTT + 0x10 * i,
 					     lvt_val | APIC_LVT_MASKED);
 			}
-			atomic_set(&apic->lapic_timer.pending, 0);
-
 		}
 		break;
 
@@ -738,7 +721,7 @@ static int apic_mmio_write(struct kvm_io
 		break;
 
 	case APIC_TMICT:
-		hrtimer_cancel(&apic->lapic_timer.timer);
+		kvm_timer_cancel(&apic->lapic_timer);
 		apic_set_reg(apic, APIC_TMICT, val);
 		start_apic_timer(apic);
 		return 0;
@@ -763,7 +746,7 @@ void kvm_free_lapic(struct kvm_vcpu *vcp
 	if (!vcpu->arch.apic)
 		return;
 
-	hrtimer_cancel(&vcpu->arch.apic->lapic_timer.timer);
+	kvm_timer_cancel(&vcpu->arch.apic->lapic_timer);
 
 	if (vcpu->arch.apic->regs_page)
 		__free_page(vcpu->arch.apic->regs_page);
@@ -834,7 +817,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vc
 	ASSERT(apic != NULL);
 
 	/* Stop the timer in case it's a reset to an active apic */
-	hrtimer_cancel(&apic->lapic_timer.timer);
+	kvm_timer_cancel(&apic->lapic_timer);
 
 	apic_set_reg(apic, APIC_ID, vcpu->vcpu_id << 24);
 	apic_set_reg(apic, APIC_LVR, APIC_VERSION);
@@ -860,7 +843,6 @@ void kvm_lapic_reset(struct kvm_vcpu *vc
 	}
 	apic->irr_pending = false;
 	update_divide_count(apic);
-	atomic_set(&apic->lapic_timer.pending, 0);
 	if (kvm_vcpu_is_bsp(vcpu))
 		vcpu->arch.apic_base |= MSR_IA32_APICBASE_BSP;
 	apic_update_ppr(apic);
@@ -889,19 +871,12 @@ int kvm_lapic_enabled(struct kvm_vcpu *v
  *----------------------------------------------------------------------
  */
 
-static bool lapic_is_periodic(struct kvm_timer *ktimer)
-{
-	struct kvm_lapic *apic = container_of(ktimer, struct kvm_lapic,
-					      lapic_timer);
-	return apic_lvtt_period(apic);
-}
-
 int apic_has_pending_timer(struct kvm_vcpu *vcpu)
 {
 	struct kvm_lapic *lapic = vcpu->arch.apic;
 
 	if (lapic && apic_enabled(lapic) && apic_lvt_enabled(lapic, APIC_LVTT))
-		return atomic_read(&lapic->lapic_timer.pending);
+		return kvm_timer_has_pending(&lapic->lapic_timer);
 
 	return 0;
 }
@@ -928,10 +903,6 @@ void kvm_apic_nmi_wd_deliver(struct kvm_
 		kvm_apic_local_deliver(apic, APIC_LVT0);
 }
 
-static struct kvm_timer_ops lapic_timer_ops = {
-	.is_periodic = lapic_is_periodic,
-};
-
 static const struct kvm_io_device_ops apic_mmio_ops = {
 	.read     = apic_mmio_read,
 	.write    = apic_mmio_write,
@@ -960,12 +931,8 @@ int kvm_create_lapic(struct kvm_vcpu *vc
 	memset(apic->regs, 0, PAGE_SIZE);
 	apic->vcpu = vcpu;
 
-	hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC,
-		     HRTIMER_MODE_ABS);
-	apic->lapic_timer.timer.function = kvm_timer_fn;
-	apic->lapic_timer.t_ops = &lapic_timer_ops;
-	apic->lapic_timer.kvm = vcpu->kvm;
-	apic->lapic_timer.vcpu = vcpu;
+	kvm_timer_init(vcpu->kvm, &apic->lapic_timer);
+	kvm_timer_vcpu_bind(&apic->lapic_timer, vcpu);
 
 	apic->base_address = APIC_DEFAULT_PHYS_BASE;
 	vcpu->arch.apic_base = APIC_DEFAULT_PHYS_BASE;
@@ -1015,9 +982,9 @@ void kvm_inject_apic_timer_irqs(struct k
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
 
-	if (apic && atomic_read(&apic->lapic_timer.pending) > 0) {
+	if (apic && kvm_timer_has_pending(&apic->lapic_timer)) {
 		if (kvm_apic_local_deliver(apic, APIC_LVTT))
-			atomic_dec(&apic->lapic_timer.pending);
+			kvm_timer_ack(&apic->lapic_timer);
 	}
 }
 
@@ -1043,24 +1010,11 @@ void kvm_apic_post_state_restore(struct 
 			     MSR_IA32_APICBASE_BASE;
 	apic_set_reg(apic, APIC_LVR, APIC_VERSION);
 	apic_update_ppr(apic);
-	hrtimer_cancel(&apic->lapic_timer.timer);
+	kvm_timer_cancel(&apic->lapic_timer);
 	update_divide_count(apic);
 	start_apic_timer(apic);
 }
 
-void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
-{
-	struct kvm_lapic *apic = vcpu->arch.apic;
-	struct hrtimer *timer;
-
-	if (!apic)
-		return;
-
-	timer = &apic->lapic_timer.timer;
-	if (hrtimer_cancel(timer))
-		hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
-}
-
 void kvm_lapic_sync_from_vapic(struct kvm_vcpu *vcpu)
 {
 	u32 data;
Index: kvm-new/arch/x86/kvm/timer.c
===================================================================
--- kvm-new.orig/arch/x86/kvm/timer.c
+++ kvm-new/arch/x86/kvm/timer.c
@@ -23,7 +23,7 @@ static int __kvm_timer_fn(struct kvm_vcp
 	if (waitqueue_active(q))
 		wake_up_interruptible(q);
 
-	if (ktimer->t_ops->is_periodic(ktimer)) {
+	if (ktimer->periodic) {
 		hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
 		restart_timer = 1;
 	}
@@ -31,7 +31,7 @@ static int __kvm_timer_fn(struct kvm_vcp
 	return restart_timer;
 }
 
-enum hrtimer_restart kvm_timer_fn(struct hrtimer *data)
+static enum hrtimer_restart kvm_timer_fn(struct hrtimer *data)
 {
 	int restart_timer;
 	struct kvm_vcpu *vcpu;
@@ -48,3 +48,58 @@ enum hrtimer_restart kvm_timer_fn(struct
 		return HRTIMER_NORESTART;
 }
 
+void kvm_timer_init(struct kvm *kvm, struct kvm_timer *ktimer)
+{
+	ktimer->kvm = kvm;
+	hrtimer_init(&ktimer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	ktimer->timer.function = kvm_timer_fn;
+}
+
+void kvm_timer_vcpu_bind(struct kvm_timer *ktimer, struct kvm_vcpu *vcpu)
+{
+	ktimer->vcpu = vcpu;
+}
+
+void kvm_timer_start(struct kvm_timer *ktimer, u64 interval, bool periodic)
+{
+	hrtimer_cancel(&ktimer->timer);
+	atomic_set(&ktimer->pending, 0);
+	ktimer->periodic = periodic;
+	ktimer->period = interval;
+	hrtimer_start(&ktimer->timer, ktime_add_ns(ktime_get(), interval),
+			HRTIMER_MODE_ABS);
+}
+
+void kvm_timer_cancel(struct kvm_timer *ktimer)
+{
+	hrtimer_cancel(&ktimer->timer);
+	atomic_set(&ktimer->pending, 0);
+}
+
+int kvm_timer_has_pending(struct kvm_timer *ktimer)
+{
+	return atomic_read(&ktimer->pending);
+}
+
+void kvm_timer_ack(struct kvm_timer *ktimer)
+{
+	if (atomic_dec_return(&ktimer->pending) < 0)
+		atomic_inc(&ktimer->pending);
+}
+
+void kvm_timer_reset(struct kvm_timer *ktimer)
+{
+	atomic_set(&ktimer->pending, 0);
+}
+
+void kvm_migrate_timer(struct kvm_timer *ktimer)
+{
+	if (hrtimer_cancel(&ktimer->timer))
+		hrtimer_start_expires(&ktimer->timer, HRTIMER_MODE_ABS);
+}
+
+ktime_t kvm_timer_remaining(struct kvm_timer *ktimer)
+{
+	return hrtimer_expires_remaining(&ktimer->timer);
+}
+
Index: kvm-new/arch/x86/kvm/i8254.h
===================================================================
--- kvm-new.orig/arch/x86/kvm/i8254.h
+++ kvm-new/arch/x86/kvm/i8254.h
@@ -22,7 +22,6 @@ struct kvm_kpit_channel_state {
 struct kvm_kpit_state {
 	struct kvm_kpit_channel_state channels[3];
 	struct kvm_timer pit_timer;
-	bool is_periodic;
 	u32    speaker_data_on;
 	struct mutex lock;
 	struct kvm_pit *pit;
@@ -52,6 +51,5 @@ void kvm_inject_pit_timer_irqs(struct kv
 void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val);
 struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags);
 void kvm_free_pit(struct kvm *kvm);
-void kvm_pit_reset(struct kvm_pit *pit);
 
 #endif
Index: kvm-new/arch/x86/kvm/irq.c
===================================================================
--- kvm-new.orig/arch/x86/kvm/irq.c
+++ kvm-new/arch/x86/kvm/irq.c
@@ -94,6 +94,26 @@ void kvm_inject_pending_timer_irqs(struc
 }
 EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
 
+static void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
+{
+	struct kvm_lapic *apic = vcpu->arch.apic;
+
+	if (!apic)
+		return;
+
+	kvm_migrate_timer(&apic->lapic_timer);
+}
+
+static void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
+{
+	struct kvm_pit *pit = vcpu->kvm->arch.vpit;
+
+	if (!kvm_vcpu_is_bsp(vcpu) || !pit)
+		return;
+
+	kvm_migrate_timer(&pit->pit_state.pit_timer);
+}
+
 void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
 {
 	__kvm_migrate_apic_timer(vcpu);
Index: kvm-new/arch/x86/kvm/irq.h
===================================================================
--- kvm-new.orig/arch/x86/kvm/irq.h
+++ kvm-new/arch/x86/kvm/irq.h
@@ -94,8 +94,6 @@ void kvm_pic_reset(struct kvm_kpic_state
 void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu);
 void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu);
 void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu);
-void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu);
-void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu);
 void __kvm_migrate_timers(struct kvm_vcpu *vcpu);
 
 int pit_has_pending_timer(struct kvm_vcpu *vcpu);
Index: kvm-new/arch/x86/kvm/x86.c
===================================================================
--- kvm-new.orig/arch/x86/kvm/x86.c
+++ kvm-new/arch/x86/kvm/x86.c
@@ -4565,6 +4565,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(st
 int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
 {
 	int r;
+	struct kvm *kvm = vcpu->kvm;
 
 	/* We do fxsave: this must be aligned. */
 	BUG_ON((unsigned long)&vcpu->arch.host_fx_image & 0xF);
@@ -4578,6 +4579,9 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu 
 	if (r < 0)
 		goto free_vcpu;
 
+	if (kvm->arch.vpit && kvm_vcpu_is_bsp(vcpu))
+		kvm_timer_vcpu_bind(&kvm->arch.vpit->pit_state.pit_timer, vcpu);
+
 	return 0;
 free_vcpu:
 	kvm_x86_ops->vcpu_free(vcpu);

--