/*
* KVM in-kernel PIT (i8254) support
*
* Copyright (c) 2003-2004 Fabrice Bellard
* Copyright (c) 2012 Jan Kiszka, Siemens AG
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/timer.h"
#include "sysemu/sysemu.h"
#include "hw/timer/i8254.h"
#include "hw/timer/i8254_internal.h"
#include "sysemu/kvm.h"
#define KVM_PIT_REINJECT_BIT 0
#define CALIBRATION_ROUNDS 3
#define KVM_PIT(obj) OBJECT_CHECK(KVMPITState, (obj), TYPE_KVM_I8254)
#define KVM_PIT_CLASS(class) \
OBJECT_CLASS_CHECK(KVMPITClass, (class), TYPE_KVM_I8254)
#define KVM_PIT_GET_CLASS(obj) \
OBJECT_GET_CLASS(KVMPITClass, (obj), TYPE_KVM_I8254)
typedef struct KVMPITState {
PITCommonState parent_obj;
LostTickPolicy lost_tick_policy;
bool vm_stopped;
int64_t kernel_clock_offset;
} KVMPITState;
typedef struct KVMPITClass {
PITCommonClass parent_class;
DeviceRealize parent_realize;
} KVMPITClass;
static int64_t abs64(int64_t v)
{
return v < 0 ? -v : v;
}
static void kvm_pit_update_clock_offset(KVMPITState *s)
{
int64_t offset, clock_offset;
struct timespec ts;
int i;
/*
* Measure the delta between CLOCK_MONOTONIC, the base used for
* kvm_pit_channel_state::count_load_time, and QEMU_CLOCK_VIRTUAL. Take the
* minimum of several samples to filter out scheduling noise.
*/
clock_offset = INT64_MAX;
for (i = 0; i < CALIBRATION_ROUNDS; i++) {
offset = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
clock_gettime(CLOCK_MONOTONIC, &ts);
offset -= ts.tv_nsec;
offset -= (int64_t)ts.tv_sec * 1000000000;
if (abs64(offset) < abs64(clock_offset)) {
clock_offset = offset;
}
}
s->kernel_clock_offset = clock_offset;
}
static void kvm_pit_get(PITCommonState *pit)
{
KVMPITState *s = KVM_PIT(pit);
struct kvm_pit_state2 kpit;
struct kvm_pit_channel_state *kchan;
struct PITChannelState *sc;
int i, ret;
/* No need to re-read the state if VM is stopped. */
if (s->vm_stopped) {
return;
}
if (kvm_has_pit_state2()) {
ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT2, &kpit);
if (ret < 0) {
fprintf(stderr, "KVM_GET_PIT2 failed: %s\n", strerror(ret));
abort();
}
pit->channels[0].irq_disabled = kpit.flags & KVM_PIT_FLAGS_HPET_LEGACY;
} else {
/*
* kvm_pit_state2 is superset of kvm_pit_state struct,
* so we can use it for KVM_GET_PIT as well.
*/
ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT, &kpit);
if (ret < 0) {
fprintf(stderr, "KVM_GET_PIT failed: %s\n", strerror(ret));
abort();
}
}
for (i = 0; i < 3; i++) {
kchan = &kpit.channels[i];
sc = &pit->channels[i];
sc->count = kchan->count;
sc->latched_count = kchan->latched_count;
sc->count_latched = kchan->count_latched;
sc->status_latched = kchan->status_latched;
sc->status = kchan->status;
sc->read_state = kchan->read_state;
sc->write_state = kchan->write_state;
sc->write_latch = kchan->write_latch;
sc->rw_mode = kchan->rw_mode;
sc->mode = kchan->mode;
sc->bcd = kchan->bcd;
sc->gate = kchan->gate;
sc->count_load_time = kchan->count_load_time + s->kernel_clock_offset;
}
sc = &pit->channels[0];
sc->next_transition_time =
pit_get_next_transition_time(sc, sc->count_load_time);
}
static void kvm_pit_put(PITCommonState *pit)
{
KVMPITState *s = KVM_PIT(pit);
struct kvm_pit_state2 kpit = {};
struct kvm_pit_channel_state *kchan;
struct PITChannelState *sc;
int i, ret;
/* The offset keeps changing as long as the VM is stopped. */
if (s->vm_stopped) {
kvm_pit_update_clock_offset(s);
}
kpit.flags = pit->channels[0].irq_disabled ? KVM_PIT_FLAGS_HPET_LEGACY : 0;
for (i = 0; i < 3; i++) {
kchan = &kpit.channels[i];
sc = &pit->channels[i];
kchan->count = sc->count;
kchan->latched_count = sc->latched_count;
kchan->count_latched = sc->count_latched;
kchan->status_latched = sc->status_latched;
kchan->status = sc->status;
kchan->read_state = sc->read_state;
kchan->write_state = sc->write_state;
kchan->write_latch = sc->write_latch;
kchan->rw_mode = sc->rw_mode;
kchan->mode = sc->mode;
kchan->bcd = sc->bcd;
kchan->gate = sc->gate;
kchan->count_load_time = sc->count_load_time - s->kernel_clock_offset;
}
ret = kvm_vm_ioctl(kvm_state,
kvm_has_pit_state2() ? KVM_SET_PIT2 : KVM_SET_PIT,
&kpit);
if (ret < 0) {
fprintf(stderr, "%s failed: %s\n",
kvm_has_pit_state2() ? "KVM_SET_PIT2" : "KVM_SET_PIT",
strerror(ret));
abort();
}
}
static void kvm_pit_set_gate(PITCommonState *s, PITChannelState *sc, int val)
{
kvm_pit_get(s);
switch (sc->mode) {
default:
case 0:
case 4:
/* XXX: just disable/enable counting */
break;
case 1:
case 2:
case 3:
case 5:
if (sc->gate < val) {
/* restart counting on rising edge */
sc->count_load_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
}
break;
}
sc->gate = val;
kvm_pit_put(s);
}
static void kvm_pit_get_channel_info(PITCommonState *s, PITChannelState *sc,
PITChannelInfo *info)
{
kvm_pit_get(s);
pit_get_channel_info_common(s, sc, info);
}
static void kvm_pit_reset(DeviceState *dev)
{
PITCommonState *s = PIT_COMMON(dev);
pit_reset_common(s);
kvm_pit_put(s);
}
static void kvm_pit_irq_control(void *opaque, int n, int enable)
{
PITCommonState *pit = opaque;
PITChannelState *s = &pit->channels[0];
kvm_pit_get(pit);
s->irq_disabled = !enable;
kvm_pit_put(pit);
}
static void kvm_pit_vm_state_change(void *opaque, int running,
RunState state)
{
KVMPITState *s = opaque;
if (running) {
kvm_pit_update_clock_offset(s);
kvm_pit_put(PIT_COMMON(s));
s->vm_stopped = false;
} else {
kvm_pit_update_clock_offset(s);
kvm_pit_get(PIT_COMMON(s));
s->vm_stopped = true;
}
}
static void kvm_pit_realizefn(DeviceState *dev, Error **errp)
{
PITCommonState *pit = PIT_COMMON(dev);
KVMPITClass *kpc = KVM_PIT_GET_CLASS(dev);
KVMPITState *s = KVM_PIT(pit);
struct kvm_pit_config config = {
.flags = 0,
};
int ret;
if (kvm_check_extension(kvm_state, KVM_CAP_PIT2)) {
ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT2, &config);
} else {
ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT);
}
if (ret < 0) {
error_setg(errp, "Create kernel PIC irqchip failed: %s",
strerror(ret));
return;
}
switch (s->lost_tick_policy) {
case LOST_TICK_POLICY_DELAY:
break; /* enabled by default */
case LOST_TICK_POLICY_DISCARD:
if (kvm_check_extension(kvm_state, KVM_CAP_REINJECT_CONTROL)) {
struct kvm_reinject_control control = { .pit_reinject = 0 };
ret = kvm_vm_ioctl(kvm_state, KVM_REINJECT_CONTROL, &control);
if (ret < 0) {
error_setg(errp,
"Can't disable in-kernel PIT reinjection: %s",
strerror(ret));
return;
}
}
break;
default:
error_setg(errp, "Lost tick policy not supported.");
return;
}
memory_region_init_reservation(&pit->ioports, NULL, "kvm-pit", 4);
qdev_init_gpio_in(dev, kvm_pit_irq_control, 1);
qemu_add_vm_change_state_handler(kvm_pit_vm_state_change, s);
kpc->parent_realize(dev, errp);
}
static Property kvm_pit_properties[] = {
DEFINE_PROP_UINT32("iobase", PITCommonState, iobase, -1),
DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", KVMPITState,
lost_tick_policy, LOST_TICK_POLICY_DELAY),
DEFINE_PROP_END_OF_LIST(),
};
static void kvm_pit_class_init(ObjectClass *klass, void *data)
{
KVMPITClass *kpc = KVM_PIT_CLASS(klass);
PITCommonClass *k = PIT_COMMON_CLASS(klass);
DeviceClass *dc = DEVICE_CLASS(klass);
kpc->parent_realize = dc->realize;
dc->realize = kvm_pit_realizefn;
k->set_channel_gate = kvm_pit_set_gate;
k->get_channel_info = kvm_pit_get_channel_info;
dc->reset = kvm_pit_reset;
dc->props = kvm_pit_properties;
}
static const TypeInfo kvm_pit_info = {
.name = TYPE_KVM_I8254,
.parent = TYPE_PIT_COMMON,
.instance_size = sizeof(KVMPITState),
.class_init = kvm_pit_class_init,
.class_size = sizeof(KVMPITClass),
};
static void kvm_pit_register(void)
{
type_register_static(&kvm_pit_info);
}
type_init(kvm_pit_register)
