Merge tag 'v3.14.43-rt42-lno1' of git://git.linaro.org/people/anders.roxell/linux-rt into linux-linaro-lsk-v3.14-rtlsk-v3.14-15.06-rt

Linux 3.14.43-rt42

Changes since v3.14.39-rt37:
- KVM: lapic: mark LAPIC timer handler as irqsafe
- KVM: use simple waitqueue for vcpu->wq
- hotplug: Use set_cpus_allowed_ptr() in sync_unplug_thread()
- rt, nohz_full: fix nohz_full for PREEMPT_RT_FULL
- kernel/irq_work: fix no_hz deadlock

* tag 'v3.14.43-rt42-lno1' of git://git.linaro.org/people/anders.roxell/linux-rt: (360 commits)
  Linux 3.14.43-rt42 REBASE
  rt, nohz_full: fix nohz_full for PREEMPT_RT_FULL
  hotplug: Use set_cpus_allowed_ptr() in sync_unplug_thread()
  KVM: use simple waitqueue for vcpu->wq
  KVM: lapic: mark LAPIC timer handler as irqsafe
  kernel/irq_work: fix no_hz deadlock
  netpoll: guard the access to dev->npinfo with rcu_read_lock/unlock_bh() for CONFIG_PREEMPT_RT_FULL=y
  Revert "timers: do not raise softirq unconditionally"
  fs,btrfs: fix rt deadlock on extent_buffer->lock
  staging: Mark rtl8821ae as broken
  timers: Reduce future __run_timers() latency for first add to empty list
  timers: Reduce future __run_timers() latency for newly emptied list
  timers: Reduce __run_timers() latency for empty list
  timers: Track total number of timers in list
  fs/aio: simple simple work
  lockdep: selftest: fix warnings due to missing PREEMPT_RT conditionals
  thermal: Defer thermal wakups to threads
  locking: ww_mutex: fix ww_mutex vs self-deadlock
  Revert "rwsem-rt: Do not allow readers to nest"
  sunrpc: make svc_xprt_do_enqueue() use get_cpu_light()
  ...

1 files changed, 42 insertions, 6 deletions

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 453e5fbbb7ae..8b25d010d5e4 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1031,8 +1031,38 @@ static void update_divide_count(struct kvm_lapic *apic)
 				   apic->divide_count);
 }
 
+
+static enum hrtimer_restart apic_timer_fn(struct hrtimer *data);
+
+static void apic_timer_expired(struct hrtimer *data)
+{
+	int ret, i = 0;
+	enum hrtimer_restart r;
+	struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
+
+	r = apic_timer_fn(data);
+
+	if (r == HRTIMER_RESTART) {
+		do {
+			ret = hrtimer_start_expires(data, HRTIMER_MODE_ABS);
+			if (ret == -ETIME)
+				hrtimer_add_expires_ns(&ktimer->timer,
+							ktimer->period);
+			i++;
+		} while (ret == -ETIME && i < 10);
+
+		if (ret == -ETIME) {
+			printk_once(KERN_ERR "%s: failed to reprogram timer\n",
+			       __func__);
+			WARN_ON_ONCE(1);
+		}
+	}
+}
+
+
 static void start_apic_timer(struct kvm_lapic *apic)
 {
+	int ret;
 	ktime_t now;
 	atomic_set(&apic->lapic_timer.pending, 0);
 
@@ -1062,9 +1092,11 @@ static void start_apic_timer(struct kvm_lapic *apic)
 			}
 		}
 
-		hrtimer_start(&apic->lapic_timer.timer,
+		ret = hrtimer_start(&apic->lapic_timer.timer,
 			      ktime_add_ns(now, apic->lapic_timer.period),
 			      HRTIMER_MODE_ABS);
+		if (ret == -ETIME)
+			apic_timer_expired(&apic->lapic_timer.timer);
 
 		apic_debug("%s: bus cycle is %" PRId64 "ns, now 0x%016"
 			   PRIx64 ", "
@@ -1094,8 +1126,10 @@ static void start_apic_timer(struct kvm_lapic *apic)
 			ns = (tscdeadline - guest_tsc) * 1000000ULL;
 			do_div(ns, this_tsc_khz);
 		}
-		hrtimer_start(&apic->lapic_timer.timer,
+		ret = hrtimer_start(&apic->lapic_timer.timer,
 			ktime_add_ns(now, ns), HRTIMER_MODE_ABS);
+		if (ret == -ETIME)
+			apic_timer_expired(&apic->lapic_timer.timer);
 
 		local_irq_restore(flags);
 	}
@@ -1533,7 +1567,7 @@ static enum hrtimer_restart apic_timer_fn(struct hrtimer *data)
 	struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
 	struct kvm_lapic *apic = container_of(ktimer, struct kvm_lapic, lapic_timer);
 	struct kvm_vcpu *vcpu = apic->vcpu;
-	wait_queue_head_t *q = &vcpu->wq;
+	struct swait_head *q = &vcpu->wq;
 
 	/*
 	 * There is a race window between reading and incrementing, but we do
@@ -1547,8 +1581,8 @@ static enum hrtimer_restart apic_timer_fn(struct hrtimer *data)
 		kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
 	}
 
-	if (waitqueue_active(q))
-		wake_up_interruptible(q);
+	if (swaitqueue_active(q))
+		swait_wake_interruptible(q);
 
 	if (lapic_is_periodic(apic)) {
 		hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
@@ -1581,6 +1615,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu)
 	hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC,
 		     HRTIMER_MODE_ABS);
 	apic->lapic_timer.timer.function = apic_timer_fn;
+	apic->lapic_timer.timer.irqsafe = 1;
 
 	/*
 	 * APIC is created enabled. This will prevent kvm_lapic_set_base from
@@ -1699,7 +1734,8 @@ void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
 
 	timer = &vcpu->arch.apic->lapic_timer.timer;
 	if (hrtimer_cancel(timer))
-		hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
+		if (hrtimer_start_expires(timer, HRTIMER_MODE_ABS) == -ETIME)
+			apic_timer_expired(timer);
 }
 
 /*