KVM: Remove internal timer abstraction

kvm_timer_fn(), the sole inhabitant of timer.c, is only used by lapic.c. Move
it there to make it easier to hack on it.

struct kvm_timer is a thin wrapper around hrtimer, and only adds obfuscation.
Move near its two users (with different names) to prepare for simplification.

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

arch/x86/kvm/Makefile

@@ -12,7 +12,7 @@ kvm-$(CONFIG_IOMMU_API)	+= $(addprefix ../../../virt/kvm/, iommu.o)
 kvm-$(CONFIG_KVM_ASYNC_PF)	+= $(addprefix ../../../virt/kvm/, async_pf.o)
 
 kvm-y			+= x86.o mmu.o emulate.o i8259.o irq.o lapic.o \
-			   i8254.o timer.o cpuid.o pmu.o
+			   i8254.o cpuid.o pmu.o
 kvm-intel-y		+= vmx.o
 kvm-amd-y		+= svm.o
 

arch/x86/kvm/i8254.c

@@ -272,14 +272,14 @@ static void destroy_pit_timer(struct kvm_pit *pit)
 	flush_kthread_work(&pit->expired);
 }
 
-static bool kpit_is_periodic(struct kvm_timer *ktimer)
+static bool kpit_is_periodic(struct kvm_pit_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 = {
+static struct kvm_pit_timer_ops kpit_ops = {
 	.is_periodic = kpit_is_periodic,
 };
 
@@ -322,7 +322,7 @@ static void pit_do_work(struct kthread_work *work)
 
 static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 {
-	struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
+	struct kvm_pit_timer *ktimer = container_of(data, struct kvm_pit_timer, timer);
 	struct kvm_pit *pt = ktimer->kvm->arch.vpit;
 
 	if (ktimer->reinject || !atomic_read(&ktimer->pending)) {
@@ -340,7 +340,7 @@ static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 static void create_pit_timer(struct kvm *kvm, u32 val, int is_period)
 {
 	struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
-	struct kvm_timer *pt = &ps->pit_timer;
+	struct kvm_pit_timer *pt = &ps->pit_timer;
 	s64 interval;
 
 	if (!irqchip_in_kernel(kvm) || ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)

arch/x86/kvm/i8254.h

@@ -21,10 +21,26 @@ struct kvm_kpit_channel_state {
 	ktime_t count_load_time;
 };
 
+struct kvm_pit_timer {
+	struct hrtimer timer;
+	s64 period; 				/* unit: ns */
+	u32 timer_mode_mask;
+	u64 tscdeadline;
+	atomic_t pending;			/* accumulated triggered timers */
+	bool reinject;
+	struct kvm_pit_timer_ops *t_ops;
+	struct kvm *kvm;
+	struct kvm_vcpu *vcpu;
+};
+
+struct kvm_pit_timer_ops {
+	bool (*is_periodic)(struct kvm_pit_timer *);
+};
+
 struct kvm_kpit_state {
 	struct kvm_kpit_channel_state channels[3];
 	u32 flags;
-	struct kvm_timer pit_timer;
+	struct kvm_pit_timer pit_timer;
 	bool is_periodic;
 	u32    speaker_data_on;
 	struct mutex lock;

arch/x86/kvm/lapic.c

@@ -1262,6 +1262,34 @@ static const struct kvm_io_device_ops apic_mmio_ops = {
 	.write    = apic_mmio_write,
 };
 
+static enum hrtimer_restart apic_timer_fn(struct hrtimer *data)
+{
+	struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
+	struct kvm_vcpu *vcpu = ktimer->vcpu;
+	wait_queue_head_t *q = &vcpu->wq;
+
+	/*
+	 * There is a race window between reading and incrementing, but we do
+	 * not care about potentially losing timer events in the !reinject
+	 * case anyway. Note: KVM_REQ_PENDING_TIMER is implicitly checked
+	 * in vcpu_enter_guest.
+	 */
+	if (ktimer->reinject || !atomic_read(&ktimer->pending)) {
+		atomic_inc(&ktimer->pending);
+		/* FIXME: this code should not know anything about vcpus */
+		kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
+	}
+
+	if (waitqueue_active(q))
+		wake_up_interruptible(q);
+
+	if (ktimer->t_ops->is_periodic(ktimer)) {
+		hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
+		return HRTIMER_RESTART;
+	} else
+		return HRTIMER_NORESTART;
+}
+
 int kvm_create_lapic(struct kvm_vcpu *vcpu)
 {
 	struct kvm_lapic *apic;
@@ -1285,7 +1313,7 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu)
 
 	hrtimer_init(&apic->lapic_timer.timer, CLOCK_MONOTONIC,
 		     HRTIMER_MODE_ABS);
-	apic->lapic_timer.timer.function = kvm_timer_fn;
+	apic->lapic_timer.timer.function = apic_timer_fn;
 	apic->lapic_timer.t_ops = &lapic_timer_ops;
 	apic->lapic_timer.kvm = vcpu->kvm;
 	apic->lapic_timer.vcpu = vcpu;

arch/x86/kvm/lapic.h

@@ -2,10 +2,25 @@
 #define __KVM_X86_LAPIC_H
 
 #include "iodev.h"
-#include "kvm_timer.h"
 
 #include <linux/kvm_host.h>
 
+struct kvm_timer {
+	struct hrtimer timer;
+	s64 period; 				/* unit: ns */
+	u32 timer_mode_mask;
+	u64 tscdeadline;
+	atomic_t pending;			/* accumulated triggered timers */
+	bool reinject;
+	struct kvm_timer_ops *t_ops;
+	struct kvm *kvm;
+	struct kvm_vcpu *vcpu;
+};
+
+struct kvm_timer_ops {
+	bool (*is_periodic)(struct kvm_timer *);
+};
+
 struct kvm_lapic {
 	unsigned long base_address;
 	struct kvm_io_device dev;