hw/i386/kvm/i8254.c - qemu - Git at Google

 /*
  * 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/osdep.h"
 #include <linux/kvm.h>
 #include "qapi/qapi-types-machine.h"
 #include "qapi/error.h"
 #include "qemu/module.h"
 #include "qemu/timer.h"
 #include "sysemu/runstate.h"
 #include "hw/timer/i8254.h"
 #include "hw/timer/i8254_internal.h"
 #include "hw/qdev-properties-system.h"
 #include "sysemu/kvm.h"
 #include "qom/object.h"

 #define KVM_PIT_REINJECT_BIT 0

 #define CALIBRATION_ROUNDS   3

 typedef struct KVMPITClass KVMPITClass;
 typedef struct KVMPITState KVMPITState;
 DECLARE_OBJ_CHECKERS(KVMPITState, KVMPITClass,
                      KVM_PIT, TYPE_KVM_I8254)

 struct KVMPITState {
     PITCommonState parent_obj;

     LostTickPolicy lost_tick_policy;
     bool vm_stopped;
     int64_t kernel_clock_offset;
 };

 struct KVMPITClass {
     PITCommonClass parent_class;

     DeviceRealize parent_realize;
 };

 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, bool 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_io(&pit->ioports, OBJECT(dev), NULL, 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);

     device_class_set_parent_realize(dc, kvm_pit_realizefn,
                                     &kpc->parent_realize);
     k->set_channel_gate = kvm_pit_set_gate;
     k->get_channel_info = kvm_pit_get_channel_info;
     dc->reset = kvm_pit_reset;
     device_class_set_props(dc, 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)
	/*
	* 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/osdep.h"
	#include <linux/kvm.h>
	#include "qapi/qapi-types-machine.h"
	#include "qapi/error.h"
	#include "qemu/module.h"
	#include "qemu/timer.h"
	#include "sysemu/runstate.h"
	#include "hw/timer/i8254.h"
	#include "hw/timer/i8254_internal.h"
	#include "hw/qdev-properties-system.h"
	#include "sysemu/kvm.h"
	#include "qom/object.h"

	#define KVM_PIT_REINJECT_BIT 0

	#define CALIBRATION_ROUNDS 3

	typedef struct KVMPITClass KVMPITClass;
	typedef struct KVMPITState KVMPITState;
	DECLARE_OBJ_CHECKERS(KVMPITState, KVMPITClass,
	KVM_PIT, TYPE_KVM_I8254)

	struct KVMPITState {
	PITCommonState parent_obj;

	LostTickPolicy lost_tick_policy;
	bool vm_stopped;
	int64_t kernel_clock_offset;
	};

	struct KVMPITClass {
	PITCommonClass parent_class;

	DeviceRealize parent_realize;
	};

	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, bool 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_io(&pit->ioports, OBJECT(dev), NULL, 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);

	device_class_set_parent_realize(dc, kvm_pit_realizefn,
	&kpc->parent_realize);
	k->set_channel_gate = kvm_pit_set_gate;
	k->get_channel_info = kvm_pit_get_channel_info;
	dc->reset = kvm_pit_reset;
	device_class_set_props(dc, 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)