KVM: unify part of generic timer handling

Hide the internals of vcpu awakening / injection from the in-kernel
emulated timers. This makes future changes in this logic easier and
decreases the distance to more generic timer handling.

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

arch/x86/kvm/Makefile

@@ -14,7 +14,7 @@ endif
 EXTRA_CFLAGS += -Ivirt/kvm -Iarch/x86/kvm
 
 kvm-objs := $(common-objs) x86.o mmu.o x86_emulate.o i8259.o irq.o lapic.o \
-	i8254.o
+	i8254.o timer.o
 obj-$(CONFIG_KVM) += kvm.o
 kvm-intel-objs = vmx.o
 obj-$(CONFIG_KVM_INTEL) += kvm-intel.o

arch/x86/kvm/i8254.c

@@ -219,25 +219,6 @@ static void pit_latch_status(struct kvm *kvm, int channel)
 	}
 }
 
-static int __pit_timer_fn(struct kvm_kpit_state *ps)
-{
-	struct kvm_vcpu *vcpu0 = ps->pit->kvm->vcpus[0];
-	struct kvm_kpit_timer *pt = &ps->pit_timer;
-
-	if (!atomic_inc_and_test(&pt->pending))
-		set_bit(KVM_REQ_PENDING_TIMER, &vcpu0->requests);
-
-	if (!pt->reinject)
-		atomic_set(&pt->pending, 1);
-
-	if (vcpu0 && waitqueue_active(&vcpu0->wq))
-		wake_up_interruptible(&vcpu0->wq);
-
-	hrtimer_add_expires_ns(&pt->timer, pt->period);
-
-	return (pt->period == 0 ? 0 : 1);
-}
-
 int pit_has_pending_timer(struct kvm_vcpu *vcpu)
 {
 	struct kvm_pit *pit = vcpu->kvm->arch.vpit;
@@ -258,21 +239,6 @@ static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
 	spin_unlock(&ps->inject_lock);
 }
 
-static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
-{
-	struct kvm_kpit_state *ps;
-	int restart_timer = 0;
-
-	ps = container_of(data, struct kvm_kpit_state, pit_timer.timer);
-
-	restart_timer = __pit_timer_fn(ps);
-
-	if (restart_timer)
-		return HRTIMER_RESTART;
-	else
-		return HRTIMER_NORESTART;
-}
-
 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 {
 	struct kvm_pit *pit = vcpu->kvm->arch.vpit;
@@ -286,15 +252,26 @@ void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 		hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 }
 
-static void destroy_pit_timer(struct kvm_kpit_timer *pt)
+static void destroy_pit_timer(struct kvm_timer *pt)
 {
 	pr_debug("pit: execute del timer!\n");
 	hrtimer_cancel(&pt->timer);
 }
 
+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;
+}
+
+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_kpit_timer *pt = &ps->pit_timer;
+	struct kvm_timer *pt = &ps->pit_timer;
 	s64 interval;
 
 	interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
@@ -304,7 +281,13 @@ static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
 	/* TODO The new value only affected after the retriggered */
 	hrtimer_cancel(&pt->timer);
 	pt->period = (is_period == 0) ? 0 : interval;
-	pt->timer.function = pit_timer_fn;
+	ps->is_periodic = is_period;
+
+	pt->timer.function = kvm_timer_fn;
+	pt->t_ops = &kpit_ops;
+	pt->kvm = ps->pit->kvm;
+	pt->vcpu_id = 0;
+
 	atomic_set(&pt->pending, 0);
 	ps->irq_ack = 1;
 

arch/x86/kvm/i8254.h

@@ -3,14 +3,6 @@
 
 #include "iodev.h"
 
-struct kvm_kpit_timer {
-	struct hrtimer timer;
-	int irq;
-	s64 period; /* unit: ns */
-	atomic_t pending;
-	bool reinject;
-};
-
 struct kvm_kpit_channel_state {
 	u32 count; /* can be 65536 */
 	u16 latched_count;
@@ -29,7 +21,8 @@ struct kvm_kpit_channel_state {
 
 struct kvm_kpit_state {
 	struct kvm_kpit_channel_state channels[3];
-	struct kvm_kpit_timer pit_timer;
+	struct kvm_timer pit_timer;
+	bool is_periodic;
 	u32    speaker_data_on;
 	struct mutex lock;
 	struct kvm_pit *pit;

arch/x86/kvm/kvm_timer.h

@@ -0,0 +1,18 @@
+
+struct kvm_timer {
+	struct hrtimer timer;
+	s64 period; 				/* unit: ns */
+	atomic_t pending;			/* accumulated triggered timers */
+	bool reinject;
+	struct kvm_timer_ops *t_ops;
+	struct kvm *kvm;
+	int vcpu_id;
+};
+
+struct kvm_timer_ops {
+        bool (*is_periodic)(struct kvm_timer *);
+};
+
+
+enum hrtimer_restart kvm_timer_fn(struct hrtimer *data);
+

arch/x86/kvm/lapic.c

@@ -528,12 +528,13 @@ static u32 apic_get_tmcct(struct kvm_lapic *apic)
 	if (apic_get_reg(apic, APIC_TMICT) == 0)
 		return 0;
 
-	remaining = hrtimer_expires_remaining(&apic->timer.dev);
+	remaining = hrtimer_expires_remaining(&apic->lapic_timer.timer);
 	if (ktime_to_ns(remaining) < 0)
 		remaining = ktime_set(0, 0);
 
-	ns = mod_64(ktime_to_ns(remaining), apic->timer.period);
-	tmcct = div64_u64(ns, (APIC_BUS_CYCLE_NS * apic->timer.divide_count));
+	ns = mod_64(ktime_to_ns(remaining), apic->lapic_timer.period);
+	tmcct = div64_u64(ns,
+			 (APIC_BUS_CYCLE_NS * apic->divide_count));
 
 	return tmcct;
 }
@@ -620,25 +621,25 @@ static void update_divide_count(struct kvm_lapic *apic)
 	tdcr = apic_get_reg(apic, APIC_TDCR);
 	tmp1 = tdcr & 0xf;
 	tmp2 = ((tmp1 & 0x3) | ((tmp1 & 0x8) >> 1)) + 1;
-	apic->timer.divide_count = 0x1 << (tmp2 & 0x7);
+	apic->divide_count = 0x1 << (tmp2 & 0x7);
 
 	apic_debug("timer divide count is 0x%x\n",
-				   apic->timer.divide_count);
+				   apic->lapic_timer.divide_count);
 }
 
 static void start_apic_timer(struct kvm_lapic *apic)
 {
-	ktime_t now = apic->timer.dev.base->get_time();
+	ktime_t now = apic->lapic_timer.timer.base->get_time();
 
-	apic->timer.period = apic_get_reg(apic, APIC_TMICT) *
-		    APIC_BUS_CYCLE_NS * apic->timer.divide_count;
-	atomic_set(&apic->timer.pending, 0);
+	apic->lapic_timer.period = apic_get_reg(apic, APIC_TMICT) *
+		    APIC_BUS_CYCLE_NS * apic->divide_count;
+	atomic_set(&apic->lapic_timer.pending, 0);
 
-	if (!apic->timer.period)
+	if (!apic->lapic_timer.period)
 		return;
 
-	hrtimer_start(&apic->timer.dev,
-		      ktime_add_ns(now, apic->timer.period),
+	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"
@@ -647,9 +648,9 @@ static void start_apic_timer(struct kvm_lapic *apic)
 			   "expire @ 0x%016" PRIx64 ".\n", __func__,
 			   APIC_BUS_CYCLE_NS, ktime_to_ns(now),
 			   apic_get_reg(apic, APIC_TMICT),
-			   apic->timer.period,
+			   apic->lapic_timer.period,
 			   ktime_to_ns(ktime_add_ns(now,
-					apic->timer.period)));
+					apic->lapic_timer.period)));
 }
 
 static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val)
@@ -731,7 +732,7 @@ static void apic_mmio_write(struct kvm_io_device *this,
 				apic_set_reg(apic, APIC_LVTT + 0x10 * i,
 					     lvt_val | APIC_LVT_MASKED);
 			}
-			atomic_set(&apic->timer.pending, 0);
+			atomic_set(&apic->lapic_timer.pending, 0);
 
 		}
 		break;
@@ -763,7 +764,7 @@ static void apic_mmio_write(struct kvm_io_device *this,
 		break;
 
 	case APIC_TMICT:
-		hrtimer_cancel(&apic->timer.dev);
+		hrtimer_cancel(&apic->lapic_timer.timer);
 		apic_set_reg(apic, APIC_TMICT, val);
 		start_apic_timer(apic);
 		return;
@@ -803,7 +804,7 @@ void kvm_free_lapic(struct kvm_vcpu *vcpu)
 	if (!vcpu->arch.apic)
 		return;
 
-	hrtimer_cancel(&vcpu->arch.apic->timer.dev);
+	hrtimer_cancel(&vcpu->arch.apic->lapic_timer.timer);
 
 	if (vcpu->arch.apic->regs_page)
 		__free_page(vcpu->arch.apic->regs_page);
@@ -881,7 +882,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu)
 	ASSERT(apic != NULL);
 
 	/* Stop the timer in case it's a reset to an active apic */
-	hrtimer_cancel(&apic->timer.dev);
+	hrtimer_cancel(&apic->lapic_timer.timer);
 
 	apic_set_reg(apic, APIC_ID, vcpu->vcpu_id << 24);
 	apic_set_reg(apic, APIC_LVR, APIC_VERSION);
@@ -906,7 +907,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu)
 		apic_set_reg(apic, APIC_TMR + 0x10 * i, 0);
 	}
 	update_divide_count(apic);
-	atomic_set(&apic->timer.pending, 0);
+	atomic_set(&apic->lapic_timer.pending, 0);
 	if (vcpu->vcpu_id == 0)
 		vcpu->arch.apic_base |= MSR_IA32_APICBASE_BSP;
 	apic_update_ppr(apic);
@@ -937,22 +938,11 @@ EXPORT_SYMBOL_GPL(kvm_lapic_enabled);
  *----------------------------------------------------------------------
  */
 
-/* TODO: make sure __apic_timer_fn runs in current pCPU */
-static int __apic_timer_fn(struct kvm_lapic *apic)
+static bool lapic_is_periodic(struct kvm_timer *ktimer)
 {
-	int result = 0;
-	wait_queue_head_t *q = &apic->vcpu->wq;
-
-	if(!atomic_inc_and_test(&apic->timer.pending))
-		set_bit(KVM_REQ_PENDING_TIMER, &apic->vcpu->requests);
-	if (waitqueue_active(q))
-		wake_up_interruptible(q);
-
-	if (apic_lvtt_period(apic)) {
-		result = 1;
-		hrtimer_add_expires_ns(&apic->timer.dev, apic->timer.period);
-	}
-	return result;
+	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)
@@ -960,7 +950,7 @@ 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->timer.pending);
+		return atomic_read(&lapic->lapic_timer.pending);
 
 	return 0;
 }
@@ -987,20 +977,9 @@ void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu)
 		kvm_apic_local_deliver(apic, APIC_LVT0);
 }
 
-static enum hrtimer_restart apic_timer_fn(struct hrtimer *data)
-{
-	struct kvm_lapic *apic;
-	int restart_timer = 0;
-
-	apic = container_of(data, struct kvm_lapic, timer.dev);
-
-	restart_timer = __apic_timer_fn(apic);
-
-	if (restart_timer)
-		return HRTIMER_RESTART;
-	else
-		return HRTIMER_NORESTART;
-}
+struct kvm_timer_ops lapic_timer_ops = {
+	.is_periodic = lapic_is_periodic,
+};
 
 int kvm_create_lapic(struct kvm_vcpu *vcpu)
 {
@@ -1025,8 +1004,13 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu)
 	memset(apic->regs, 0, PAGE_SIZE);
 	apic->vcpu = vcpu;
 
-	hrtimer_init(&apic->timer.dev, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
-	apic->timer.dev.function = apic_timer_fn;
+	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_id = vcpu->vcpu_id;
+
 	apic->base_address = APIC_DEFAULT_PHYS_BASE;
 	vcpu->arch.apic_base = APIC_DEFAULT_PHYS_BASE;
 
@@ -1079,9 +1063,9 @@ void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;
 
-	if (apic && atomic_read(&apic->timer.pending) > 0) {
+	if (apic && atomic_read(&apic->lapic_timer.pending) > 0) {
 		if (kvm_apic_local_deliver(apic, APIC_LVTT))
-			atomic_dec(&apic->timer.pending);
+			atomic_dec(&apic->lapic_timer.pending);
 	}
 }
 
@@ -1107,7 +1091,7 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu)
 			     MSR_IA32_APICBASE_BASE;
 	apic_set_reg(apic, APIC_LVR, APIC_VERSION);
 	apic_update_ppr(apic);
-	hrtimer_cancel(&apic->timer.dev);
+	hrtimer_cancel(&apic->lapic_timer.timer);
 	update_divide_count(apic);
 	start_apic_timer(apic);
 }
@@ -1120,7 +1104,7 @@ void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
 	if (!apic)
 		return;
 
-	timer = &apic->timer.dev;
+	timer = &apic->lapic_timer.timer;
 	if (hrtimer_cancel(timer))
 		hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 }

arch/x86/kvm/lapic.h

@@ -2,18 +2,15 @@
 #define __KVM_X86_LAPIC_H
 
 #include "iodev.h"
+#include "kvm_timer.h"
 
 #include <linux/kvm_host.h>
 
 struct kvm_lapic {
 	unsigned long base_address;
 	struct kvm_io_device dev;
-	struct {
-		atomic_t pending;
-		s64 period;	/* unit: ns */
-		u32 divide_count;
-		struct hrtimer dev;
-	} timer;
+	struct kvm_timer lapic_timer;
+	u32 divide_count;
 	struct kvm_vcpu *vcpu;
 	struct page *regs_page;
 	void *regs;

arch/x86/kvm/timer.c

@@ -0,0 +1,46 @@
+#include <linux/kvm_host.h>
+#include <linux/kvm.h>
+#include <linux/hrtimer.h>
+#include <asm/atomic.h>
+#include "kvm_timer.h"
+
+static int __kvm_timer_fn(struct kvm_vcpu *vcpu, struct kvm_timer *ktimer)
+{
+	int restart_timer = 0;
+	wait_queue_head_t *q = &vcpu->wq;
+
+	/* FIXME: this code should not know anything about vcpus */
+	if (!atomic_inc_and_test(&ktimer->pending))
+		set_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
+
+	if (!ktimer->reinject)
+		atomic_set(&ktimer->pending, 1);
+
+	if (waitqueue_active(q))
+		wake_up_interruptible(q);
+
+	if (ktimer->t_ops->is_periodic(ktimer)) {
+		hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
+		restart_timer = 1;
+	}
+
+	return restart_timer;
+}
+
+enum hrtimer_restart kvm_timer_fn(struct hrtimer *data)
+{
+	int restart_timer;
+	struct kvm_vcpu *vcpu;
+	struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
+
+	vcpu = ktimer->kvm->vcpus[ktimer->vcpu_id];
+	if (!vcpu)
+		return HRTIMER_NORESTART;
+
+	restart_timer = __kvm_timer_fn(vcpu, ktimer);
+	if (restart_timer)
+		return HRTIMER_RESTART;
+	else
+		return HRTIMER_NORESTART;
+}
+