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Diffstat (limited to 'arch/x86/kvm/i8254.c')
-rw-r--r--arch/x86/kvm/i8254.c376
1 files changed, 235 insertions, 141 deletions
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 4d6f0d293ee..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
@@ -29,10 +30,14 @@
* Based on QEMU and Xen.
*/
+#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))
@@ -104,6 +109,9 @@ static s64 __kpit_elapsed(struct kvm *kvm)
ktime_t remaining;
struct kvm_kpit_state *ps = &kvm->arch.vpit->pit_state;
+ if (!ps->period)
+ return 0;
+
/*
* The Counter does not stop when it reaches zero. In
* Modes 0, 1, 4, and 5 the Counter ``wraps around'' to
@@ -113,9 +121,8 @@ static s64 __kpit_elapsed(struct kvm *kvm)
* itself with the initial count and continues counting
* from there.
*/
- remaining = hrtimer_expires_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;
}
@@ -224,22 +231,24 @@ 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 && vcpu->vcpu_id == 0 && 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);
+ int value;
+
spin_lock(&ps->inject_lock);
- if (atomic_dec_return(&ps->pit_timer.pending) < 0)
- atomic_inc(&ps->pit_timer.pending);
+ 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;
spin_unlock(&ps->inject_lock);
}
@@ -249,54 +258,116 @@ void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
struct kvm_pit *pit = vcpu->kvm->arch.vpit;
struct hrtimer *timer;
- if (vcpu->vcpu_id != 0 || !pit)
+ 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("pit: 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;
-static void create_pit_timer(struct kvm_kpit_state *ps, u32 val, int is_period)
+ if (ps->reinject || !atomic_read(&ps->pending)) {
+ atomic_inc(&ps->pending);
+ queue_kthread_work(&pt->worker, &pt->expired);
+ }
+
+ 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("pit: create pit timer, interval is %llu nsec\n", interval);
+ 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_id = 0;
+ 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);
}
@@ -306,7 +377,7 @@ static void pit_load_count(struct kvm *kvm, int channel, u32 val)
WARN_ON(!mutex_is_locked(&ps->lock));
- pr_debug("pit: load_count val is %d, channel is %d\n", val, channel);
+ pr_debug("load_count val is %d, channel is %d\n", val, channel);
/*
* The largest possible initial count is 0; this is equivalent
@@ -329,33 +400,58 @@ static void pit_load_count(struct kvm *kvm, int channel, u32 val)
case 1:
/* FIXME: enhance mode 4 precision */
case 4:
- create_pit_timer(ps, val, 0);
+ create_pit_timer(kvm, val, 0);
break;
case 2:
case 3:
- 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);
}
}
-void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val)
+void kvm_pit_load_count(struct kvm *kvm, int channel, u32 val, int hpet_legacy_start)
+{
+ u8 saved_mode;
+ if (hpet_legacy_start) {
+ /* save existing mode for later reenablement */
+ saved_mode = kvm->arch.vpit->pit_state.channels[0].mode;
+ kvm->arch.vpit->pit_state.channels[0].mode = 0xff; /* disable timer */
+ pit_load_count(kvm, channel, val);
+ kvm->arch.vpit->pit_state.channels[0].mode = saved_mode;
+ } else {
+ pit_load_count(kvm, channel, val);
+ }
+}
+
+static inline struct kvm_pit *dev_to_pit(struct kvm_io_device *dev)
+{
+ return container_of(dev, struct kvm_pit, dev);
+}
+
+static inline struct kvm_pit *speaker_to_pit(struct kvm_io_device *dev)
+{
+ return container_of(dev, struct kvm_pit, speaker_dev);
+}
+
+static inline int pit_in_range(gpa_t addr)
{
- mutex_lock(&kvm->arch.vpit->pit_state.lock);
- pit_load_count(kvm, channel, val);
- mutex_unlock(&kvm->arch.vpit->pit_state.lock);
+ return ((addr >= KVM_PIT_BASE_ADDRESS) &&
+ (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
}
-static void pit_ioport_write(struct kvm_io_device *this,
- gpa_t addr, int len, const void *data)
+static int pit_ioport_write(struct kvm_io_device *this,
+ gpa_t addr, int len, const void *data)
{
- struct kvm_pit *pit = (struct kvm_pit *)this->private;
+ struct kvm_pit *pit = dev_to_pit(this);
struct kvm_kpit_state *pit_state = &pit->pit_state;
struct kvm *kvm = pit->kvm;
int channel, access;
struct kvm_kpit_channel_state *s;
u32 val = *(u32 *) data;
+ if (!pit_in_range(addr))
+ return -EOPNOTSUPP;
val &= 0xff;
addr &= KVM_PIT_CHANNEL_MASK;
@@ -363,8 +459,8 @@ static void pit_ioport_write(struct kvm_io_device *this,
mutex_lock(&pit_state->lock);
if (val != 0)
- pr_debug("pit: write addr is 0x%x, len is %d, val is 0x%x\n",
- (unsigned int)addr, len, val);
+ pr_debug("write addr is 0x%x, len is %d, val is 0x%x\n",
+ (unsigned int)addr, len, val);
if (addr == 3) {
channel = val >> 6;
@@ -418,18 +514,24 @@ static void pit_ioport_write(struct kvm_io_device *this,
}
mutex_unlock(&pit_state->lock);
+ return 0;
}
-static void pit_ioport_read(struct kvm_io_device *this,
- gpa_t addr, int len, void *data)
+static int pit_ioport_read(struct kvm_io_device *this,
+ gpa_t addr, int len, void *data)
{
- struct kvm_pit *pit = (struct kvm_pit *)this->private;
+ struct kvm_pit *pit = dev_to_pit(this);
struct kvm_kpit_state *pit_state = &pit->pit_state;
struct kvm *kvm = pit->kvm;
int ret, count;
struct kvm_kpit_channel_state *s;
+ if (!pit_in_range(addr))
+ return -EOPNOTSUPP;
addr &= KVM_PIT_CHANNEL_MASK;
+ if (addr == 3)
+ return 0;
+
s = &pit_state->channels[addr];
mutex_lock(&pit_state->lock);
@@ -482,37 +584,36 @@ static void pit_ioport_read(struct kvm_io_device *this,
memcpy(data, (char *)&ret, len);
mutex_unlock(&pit_state->lock);
+ return 0;
}
-static int pit_in_range(struct kvm_io_device *this, gpa_t addr,
- int len, int is_write)
-{
- return ((addr >= KVM_PIT_BASE_ADDRESS) &&
- (addr < KVM_PIT_BASE_ADDRESS + KVM_PIT_MEM_LENGTH));
-}
-
-static void speaker_ioport_write(struct kvm_io_device *this,
- gpa_t addr, int len, const void *data)
+static int speaker_ioport_write(struct kvm_io_device *this,
+ gpa_t addr, int len, const void *data)
{
- struct kvm_pit *pit = (struct kvm_pit *)this->private;
+ struct kvm_pit *pit = speaker_to_pit(this);
struct kvm_kpit_state *pit_state = &pit->pit_state;
struct kvm *kvm = pit->kvm;
u32 val = *(u32 *) data;
+ if (addr != KVM_SPEAKER_BASE_ADDRESS)
+ return -EOPNOTSUPP;
mutex_lock(&pit_state->lock);
pit_state->speaker_data_on = (val >> 1) & 1;
pit_set_gate(kvm, 2, val & 1);
mutex_unlock(&pit_state->lock);
+ return 0;
}
-static void speaker_ioport_read(struct kvm_io_device *this,
- gpa_t addr, int len, void *data)
+static int speaker_ioport_read(struct kvm_io_device *this,
+ gpa_t addr, int len, void *data)
{
- struct kvm_pit *pit = (struct kvm_pit *)this->private;
+ struct kvm_pit *pit = speaker_to_pit(this);
struct kvm_kpit_state *pit_state = &pit->pit_state;
struct kvm *kvm = pit->kvm;
unsigned int refresh_clock;
int ret;
+ if (addr != KVM_SPEAKER_BASE_ADDRESS)
+ return -EOPNOTSUPP;
/* Refresh clock toggles at about 15us. We approximate as 2^14ns. */
refresh_clock = ((unsigned int)ktime_to_ns(ktime_get()) >> 14) & 1;
@@ -524,12 +625,7 @@ static void speaker_ioport_read(struct kvm_io_device *this,
len = sizeof(ret);
memcpy(data, (char *)&ret, len);
mutex_unlock(&pit_state->lock);
-}
-
-static int speaker_in_range(struct kvm_io_device *this, gpa_t addr,
- int len, int is_write)
-{
- return (addr == KVM_SPEAKER_BASE_ADDRESS);
+ return 0;
}
void kvm_pit_reset(struct kvm_pit *pit)
@@ -538,6 +634,7 @@ void kvm_pit_reset(struct kvm_pit *pit)
struct kvm_kpit_channel_state *c;
mutex_lock(&pit->pit_state.lock);
+ pit->pit_state.flags = 0;
for (i = 0; i < 3; i++) {
c = &pit->pit_state.channels[i];
c->mode = 0xff;
@@ -546,7 +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;
}
@@ -555,15 +652,29 @@ 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;
}
}
-struct kvm_pit *kvm_create_pit(struct kvm *kvm)
+static const struct kvm_io_device_ops pit_dev_ops = {
+ .read = pit_ioport_read,
+ .write = pit_ioport_write,
+};
+
+static const struct kvm_io_device_ops speaker_dev_ops = {
+ .read = speaker_ioport_read,
+ .write = speaker_ioport_write,
+};
+
+/* Caller must hold slots_lock */
+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);
if (!pit)
@@ -579,30 +690,31 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm)
mutex_lock(&pit->pit_state.lock);
spin_lock_init(&pit->pit_state.inject_lock);
- /* Initialize PIO device */
- pit->dev.read = pit_ioport_read;
- pit->dev.write = pit_ioport_write;
- pit->dev.in_range = pit_in_range;
- pit->dev.private = pit;
- kvm_io_bus_register_dev(&kvm->pio_bus, &pit->dev);
+ pid = get_pid(task_tgid(current));
+ pid_nr = pid_vnr(pid);
+ put_pid(pid);
- pit->speaker_dev.read = speaker_ioport_read;
- pit->speaker_dev.write = speaker_ioport_write;
- pit->speaker_dev.in_range = speaker_in_range;
- pit->speaker_dev.private = pit;
- kvm_io_bus_register_dev(&kvm->pio_bus, &pit->speaker_dev);
+ 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);
@@ -610,7 +722,33 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm)
pit->mask_notifier.func = pit_mask_notifer;
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, 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,
+ KVM_SPEAKER_BASE_ADDRESS, 4,
+ &pit->speaker_dev);
+ if (ret < 0)
+ goto fail_unregister;
+ }
+
return pit;
+
+fail_unregister:
+ kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
+
+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;
}
void kvm_free_pit(struct kvm *kvm)
@@ -618,64 +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;
-
- mutex_lock(&kvm->lock);
- kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
- kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
- mutex_unlock(&kvm->lock);
-
- /*
- * 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)
- for (i = 0; i < KVM_MAX_VCPUS; ++i) {
- vcpu = kvm->vcpus[i];
- if (vcpu)
- 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 (vcpu && pit) {
- int inject = 0;
- ps = &pit->pit_state;
-
- /* Try to inject pending interrupts when
- * last one has been acked.
- */
- spin_lock(&ps->inject_lock);
- if (atomic_read(&ps->pit_timer.pending) && ps->irq_ack) {
- ps->irq_ack = 0;
- inject = 1;
- }
- spin_unlock(&ps->inject_lock);
- if (inject)
- __inject_pit_timer_intr(kvm);
- }
-}