1 files changed, 140 insertions, 101 deletions

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 294698b6daf..518d86471b7 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -5,6 +5,7 @@
  * Copyright (c) 2006 Intel Corporation
  * Copyright (c) 2007 Keir Fraser, XenSource Inc
  * Copyright (c) 2008 Intel Corporation
+ * Copyright 2009 Red Hat, Inc. and/or its affiliates.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -32,9 +33,11 @@
 #define pr_fmt(fmt) "pit: " fmt
 
 #include <linux/kvm_host.h>
+#include <linux/slab.h>
 
 #include "irq.h"
 #include "i8254.h"
+#include "x86.h"
 
 #ifndef CONFIG_X86_64
 #define mod_64(x, y) ((x) - (y) * div64_u64(x, y))
@@ -106,7 +109,7 @@ static s64 __kpit_elapsed(struct kvm *kvm)
 	ktime_t remaining;
 	struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 
-	if (!ps->pit_timer.period)
+	if (!ps->period)
 		return 0;
 
 	/*
@@ -118,9 +121,8 @@ static s64 __kpit_elapsed(struct kvm *kvm)
 	 * itself with the initial count and continues counting
 	 * from there.
 	 */
-	remaining = hrtimer_get_remaining(&ps->pit_timer.timer);
-	elapsed = ps->pit_timer.period - ktime_to_ns(remaining);
-	elapsed = mod_64(elapsed, ps->pit_timer.period);
+	remaining = hrtimer_get_remaining(&ps->timer);
+	elapsed = ps->period - ktime_to_ns(remaining);
 
 	return elapsed;
 }
@@ -229,24 +231,26 @@ static void pit_latch_status(struct kvm *kvm, int channel)
 	}
 }
 
-int pit_has_pending_timer(struct kvm_vcpu *vcpu)
-{
-	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 0;
-}
-
 static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 {
 	struct kvm_kpit_state *ps = container_of(kian, struct kvm_kpit_state,
 						 irq_ack_notifier);
-	raw_spin_lock(&ps->inject_lock);
-	if (atomic_dec_return(&ps->pit_timer.pending) < 0)
-		atomic_inc(&ps->pit_timer.pending);
+	int value;
+
+	spin_lock(&ps->inject_lock);
+	value = atomic_dec_return(&ps->pending);
+	if (value < 0)
+		/* spurious acks can be generated if, for example, the
+		 * PIC is being reset.  Handle it gracefully here
+		 */
+		atomic_inc(&ps->pending);
+	else if (value > 0)
+		/* in this case, we had multiple outstanding pit interrupts
+		 * that we needed to inject.  Reinject
+		 */
+		queue_kthread_work(&ps->pit->worker, &ps->pit->expired);
 	ps->irq_ack = 1;
-	raw_spin_unlock(&ps->inject_lock);
+	spin_unlock(&ps->inject_lock);
 }
 
 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
@@ -257,51 +261,113 @@ void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 	if (!kvm_vcpu_is_bsp(vcpu) || !pit)
 		return;
 
-	timer = &pit->pit_state.pit_timer.timer;
+	timer = &pit->pit_state.timer;
 	if (hrtimer_cancel(timer))
 		hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 }
 
-static void destroy_pit_timer(struct kvm_timer *pt)
+static void destroy_pit_timer(struct kvm_pit *pit)
 {
-	pr_debug("execute del timer!\n");
-	hrtimer_cancel(&pt->timer);
+	hrtimer_cancel(&pit->pit_state.timer);
+	flush_kthread_work(&pit->expired);
 }
 
-static bool kpit_is_periodic(struct kvm_timer *ktimer)
+static void pit_do_work(struct kthread_work *work)
 {
-	struct kvm_kpit_state *ps = container_of(ktimer, struct kvm_kpit_state,
-						 pit_timer);
-	return ps->is_periodic;
+	struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
+	struct kvm *kvm = pit->kvm;
+	struct kvm_vcpu *vcpu;
+	int i;
+	struct kvm_kpit_state *ps = &pit->pit_state;
+	int inject = 0;
+
+	/* Try to inject pending interrupts when
+	 * last one has been acked.
+	 */
+	spin_lock(&ps->inject_lock);
+	if (ps->irq_ack) {
+		ps->irq_ack = 0;
+		inject = 1;
+	}
+	spin_unlock(&ps->inject_lock);
+	if (inject) {
+		kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1, false);
+		kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0, false);
+
+		/*
+		 * Provides NMI watchdog support via Virtual Wire mode.
+		 * The route is: PIT -> PIC -> LVT0 in NMI mode.
+		 *
+		 * Note: Our Virtual Wire implementation is simplified, only
+		 * propagating PIT interrupts to all VCPUs when they have set
+		 * LVT0 to NMI delivery. Other PIC interrupts are just sent to
+		 * VCPU0, and only if its LVT0 is in EXTINT mode.
+		 */
+		if (kvm->arch.vapics_in_nmi_mode > 0)
+			kvm_for_each_vcpu(i, vcpu, kvm)
+				kvm_apic_nmi_wd_deliver(vcpu);
+	}
 }
 
-static struct kvm_timer_ops kpit_ops = {
-	.is_periodic = kpit_is_periodic,
-};
+static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
+{
+	struct kvm_kpit_state *ps = container_of(data, struct kvm_kpit_state, timer);
+	struct kvm_pit *pt = ps->kvm->arch.vpit;
+
+	if (ps->reinject || !atomic_read(&ps->pending)) {
+		atomic_inc(&ps->pending);
+		queue_kthread_work(&pt->worker, &pt->expired);
+	}
 
-static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
+	if (ps->is_periodic) {
+		hrtimer_add_expires_ns(&ps->timer, ps->period);
+		return HRTIMER_RESTART;
+	} else
+		return HRTIMER_NORESTART;
+}
+
+static void create_pit_timer(struct kvm *kvm, u32 val, int is_period)
 {
-	struct kvm_timer *pt = &ps->pit_timer;
+	struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
 	s64 interval;
 
+	if (!irqchip_in_kernel(kvm) || ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)
+		return;
+
 	interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
 
 	pr_debug("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;
+	hrtimer_cancel(&ps->timer);
+	flush_kthread_work(&ps->pit->expired);
+	ps->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;
+	ps->timer.function = pit_timer_fn;
+	ps->kvm = ps->pit->kvm;
 
-	atomic_set(&pt->pending, 0);
+	atomic_set(&ps->pending, 0);
 	ps->irq_ack = 1;
 
-	hrtimer_start(&pt->timer, ktime_add_ns(ktime_get(), interval),
+	/*
+	 * Do not allow the guest to program periodic timers with small
+	 * interval, since the hrtimers are not throttled by the host
+	 * scheduler.
+	 */
+	if (ps->is_periodic) {
+		s64 min_period = min_timer_period_us * 1000LL;
+
+		if (ps->period < min_period) {
+			pr_info_ratelimited(
+			    "kvm: requested %lld ns "
+			    "i8254 timer period limited to %lld ns\n",
+			    ps->period, min_period);
+			ps->period = min_period;
+		}
+	}
+
+	hrtimer_start(&ps->timer, ktime_add_ns(ktime_get(), interval),
 		      HRTIMER_MODE_ABS);
 }
 
@@ -334,18 +400,14 @@ static void pit_load_count(struct kvm *kvm, int channel, u32 val)
 	case 1:
         /* FIXME: enhance mode 4 precision */
 	case 4:
-		if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)) {
-			create_pit_timer(ps, val, 0);
-		}
+		create_pit_timer(kvm, val, 0);
 		break;
 	case 2:
 	case 3:
-		if (!(ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)){
-			create_pit_timer(ps, val, 1);
-		}
+		create_pit_timer(kvm, val, 1);
 		break;
 	default:
-		destroy_pit_timer(&ps->pit_timer);
+		destroy_pit_timer(kvm->arch.vpit);
 	}
 }
 
@@ -581,7 +643,7 @@ void kvm_pit_reset(struct kvm_pit *pit)
 	}
 	mutex_unlock(&pit->pit_state.lock);
 
-	atomic_set(&pit->pit_state.pit_timer.pending, 0);
+	atomic_set(&pit->pit_state.pending, 0);
 	pit->pit_state.irq_ack = 1;
 }
 
@@ -590,7 +652,7 @@ static void pit_mask_notifer(struct kvm_irq_mask_notifier *kimn, bool mask)
 	struct kvm_pit *pit = container_of(kimn, struct kvm_pit, mask_notifier);
 
 	if (!mask) {
-		atomic_set(&pit->pit_state.pit_timer.pending, 0);
+		atomic_set(&pit->pit_state.pending, 0);
 		pit->pit_state.irq_ack = 1;
 	}
 }
@@ -610,6 +672,8 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 {
 	struct kvm_pit *pit;
 	struct kvm_kpit_state *pit_state;
+	struct pid *pid;
+	pid_t pid_nr;
 	int ret;
 
 	pit = kzalloc(sizeof(struct kvm_pit), GFP_KERNEL);
@@ -624,19 +688,33 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 
 	mutex_init(&pit->pit_state.lock);
 	mutex_lock(&pit->pit_state.lock);
-	raw_spin_lock_init(&pit->pit_state.inject_lock);
+	spin_lock_init(&pit->pit_state.inject_lock);
+
+	pid = get_pid(task_tgid(current));
+	pid_nr = pid_vnr(pid);
+	put_pid(pid);
+
+	init_kthread_worker(&pit->worker);
+	pit->worker_task = kthread_run(kthread_worker_fn, &pit->worker,
+				       "kvm-pit/%d", pid_nr);
+	if (IS_ERR(pit->worker_task)) {
+		mutex_unlock(&pit->pit_state.lock);
+		kvm_free_irq_source_id(kvm, pit->irq_source_id);
+		kfree(pit);
+		return NULL;
+	}
+	init_kthread_work(&pit->expired, pit_do_work);
 
 	kvm->arch.vpit = pit;
 	pit->kvm = kvm;
 
 	pit_state = &pit->pit_state;
 	pit_state->pit = pit;
-	hrtimer_init(&pit_state->pit_timer.timer,
-		     CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	hrtimer_init(&pit_state->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
 	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);
-	pit_state->pit_timer.reinject = true;
+	pit_state->reinject = true;
 	mutex_unlock(&pit->pit_state.lock);
 
 	kvm_pit_reset(pit);
@@ -645,14 +723,16 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
 	kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 
 	kvm_iodevice_init(&pit->dev, &pit_dev_ops);
-	ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, &pit->dev);
+	ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, KVM_PIT_BASE_ADDRESS,
+				      KVM_PIT_MEM_LENGTH, &pit->dev);
 	if (ret < 0)
 		goto fail;
 
 	if (flags & KVM_PIT_SPEAKER_DUMMY) {
 		kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
 		ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
-						&pit->speaker_dev);
+					      KVM_SPEAKER_BASE_ADDRESS, 4,
+					      &pit->speaker_dev);
 		if (ret < 0)
 			goto fail_unregister;
 	}
@@ -666,7 +746,7 @@ fail:
 	kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 	kvm_unregister_irq_ack_notifier(kvm, &pit_state->irq_ack_notifier);
 	kvm_free_irq_source_id(kvm, pit->irq_source_id);
-
+	kthread_stop(pit->worker_task);
 	kfree(pit);
 	return NULL;
 }
@@ -676,61 +756,20 @@ void kvm_free_pit(struct kvm *kvm)
 	struct hrtimer *timer;
 
 	if (kvm->arch.vpit) {
+		kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &kvm->arch.vpit->dev);
+		kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS,
+					      &kvm->arch.vpit->speaker_dev);
 		kvm_unregister_irq_mask_notifier(kvm, 0,
 					       &kvm->arch.vpit->mask_notifier);
 		kvm_unregister_irq_ack_notifier(kvm,
 				&kvm->arch.vpit->pit_state.irq_ack_notifier);
 		mutex_lock(&kvm->arch.vpit->pit_state.lock);
-		timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
+		timer = &kvm->arch.vpit->pit_state.timer;
 		hrtimer_cancel(timer);
+		flush_kthread_work(&kvm->arch.vpit->expired);
+		kthread_stop(kvm->arch.vpit->worker_task);
 		kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
 		mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 		kfree(kvm->arch.vpit);
 	}
 }
-
-static void __inject_pit_timer_intr(struct kvm *kvm)
-{
-	struct kvm_vcpu *vcpu;
-	int i;
-
-	kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
-	kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
-
-	/*
-	 * Provides NMI watchdog support via Virtual Wire mode.
-	 * The route is: PIT -> PIC -> LVT0 in NMI mode.
-	 *
-	 * Note: Our Virtual Wire implementation is simplified, only
-	 * propagating PIT interrupts to all VCPUs when they have set
-	 * LVT0 to NMI delivery. Other PIC interrupts are just sent to
-	 * VCPU0, and only if its LVT0 is in EXTINT mode.
-	 */
-	if (kvm->arch.vapics_in_nmi_mode > 0)
-		kvm_for_each_vcpu(i, vcpu, kvm)
-			kvm_apic_nmi_wd_deliver(vcpu);
-}
-
-void kvm_inject_pit_timer_irqs(struct kvm_vcpu *vcpu)
-{
-	struct kvm_pit *pit = vcpu->kvm->arch.vpit;
-	struct kvm *kvm = vcpu->kvm;
-	struct kvm_kpit_state *ps;
-
-	if (pit) {
-		int inject = 0;
-		ps = &pit->pit_state;
-
-		/* Try to inject pending interrupts when
-		 * last one has been acked.
-		 */
-		raw_spin_lock(&ps->inject_lock);
-		if (atomic_read(&ps->pit_timer.pending) && ps->irq_ack) {
-			ps->irq_ack = 0;
-			inject = 1;
-		}
-		raw_spin_unlock(&ps->inject_lock);
-		if (inject)
-			__inject_pit_timer_intr(kvm);
-	}
-}