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