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Annotation of qemu/hw/kvm/i8254.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * KVM in-kernel PIT (i8254) support
        !             3:  *
        !             4:  * Copyright (c) 2003-2004 Fabrice Bellard
        !             5:  * Copyright (c) 2012      Jan Kiszka, Siemens AG
        !             6:  *
        !             7:  * Permission is hereby granted, free of charge, to any person obtaining a copy
        !             8:  * of this software and associated documentation files (the "Software"), to deal
        !             9:  * in the Software without restriction, including without limitation the rights
        !            10:  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
        !            11:  * copies of the Software, and to permit persons to whom the Software is
        !            12:  * furnished to do so, subject to the following conditions:
        !            13:  *
        !            14:  * The above copyright notice and this permission notice shall be included in
        !            15:  * all copies or substantial portions of the Software.
        !            16:  *
        !            17:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
        !            18:  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
        !            19:  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
        !            20:  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
        !            21:  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
        !            22:  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
        !            23:  * THE SOFTWARE.
        !            24:  */
        !            25: #include "qemu-timer.h"
        !            26: #include "sysemu.h"
        !            27: #include "hw/i8254.h"
        !            28: #include "hw/i8254_internal.h"
        !            29: #include "kvm.h"
        !            30: 
        !            31: #define KVM_PIT_REINJECT_BIT 0
        !            32: 
        !            33: #define CALIBRATION_ROUNDS   3
        !            34: 
        !            35: typedef struct KVMPITState {
        !            36:     PITCommonState pit;
        !            37:     LostTickPolicy lost_tick_policy;
        !            38:     bool state_valid;
        !            39: } KVMPITState;
        !            40: 
        !            41: static int64_t abs64(int64_t v)
        !            42: {
        !            43:     return v < 0 ? -v : v;
        !            44: }
        !            45: 
        !            46: static void kvm_pit_get(PITCommonState *pit)
        !            47: {
        !            48:     KVMPITState *s = DO_UPCAST(KVMPITState, pit, pit);
        !            49:     struct kvm_pit_state2 kpit;
        !            50:     struct kvm_pit_channel_state *kchan;
        !            51:     struct PITChannelState *sc;
        !            52:     int64_t offset, clock_offset;
        !            53:     struct timespec ts;
        !            54:     int i, ret;
        !            55: 
        !            56:     if (s->state_valid) {
        !            57:         return;
        !            58:     }
        !            59: 
        !            60:     /*
        !            61:      * Measure the delta between CLOCK_MONOTONIC, the base used for
        !            62:      * kvm_pit_channel_state::count_load_time, and vm_clock. Take the
        !            63:      * minimum of several samples to filter out scheduling noise.
        !            64:      */
        !            65:     clock_offset = INT64_MAX;
        !            66:     for (i = 0; i < CALIBRATION_ROUNDS; i++) {
        !            67:         offset = qemu_get_clock_ns(vm_clock);
        !            68:         clock_gettime(CLOCK_MONOTONIC, &ts);
        !            69:         offset -= ts.tv_nsec;
        !            70:         offset -= (int64_t)ts.tv_sec * 1000000000;
        !            71:         if (abs64(offset) < abs64(clock_offset)) {
        !            72:             clock_offset = offset;
        !            73:         }
        !            74:     }
        !            75: 
        !            76:     if (kvm_has_pit_state2()) {
        !            77:         ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT2, &kpit);
        !            78:         if (ret < 0) {
        !            79:             fprintf(stderr, "KVM_GET_PIT2 failed: %s\n", strerror(ret));
        !            80:             abort();
        !            81:         }
        !            82:         pit->channels[0].irq_disabled = kpit.flags & KVM_PIT_FLAGS_HPET_LEGACY;
        !            83:     } else {
        !            84:         /*
        !            85:          * kvm_pit_state2 is superset of kvm_pit_state struct,
        !            86:          * so we can use it for KVM_GET_PIT as well.
        !            87:          */
        !            88:         ret = kvm_vm_ioctl(kvm_state, KVM_GET_PIT, &kpit);
        !            89:         if (ret < 0) {
        !            90:             fprintf(stderr, "KVM_GET_PIT failed: %s\n", strerror(ret));
        !            91:             abort();
        !            92:         }
        !            93:     }
        !            94:     for (i = 0; i < 3; i++) {
        !            95:         kchan = &kpit.channels[i];
        !            96:         sc = &pit->channels[i];
        !            97:         sc->count = kchan->count;
        !            98:         sc->latched_count = kchan->latched_count;
        !            99:         sc->count_latched = kchan->count_latched;
        !           100:         sc->status_latched = kchan->status_latched;
        !           101:         sc->status = kchan->status;
        !           102:         sc->read_state = kchan->read_state;
        !           103:         sc->write_state = kchan->write_state;
        !           104:         sc->write_latch = kchan->write_latch;
        !           105:         sc->rw_mode = kchan->rw_mode;
        !           106:         sc->mode = kchan->mode;
        !           107:         sc->bcd = kchan->bcd;
        !           108:         sc->gate = kchan->gate;
        !           109:         sc->count_load_time = kchan->count_load_time + clock_offset;
        !           110:     }
        !           111: 
        !           112:     sc = &pit->channels[0];
        !           113:     sc->next_transition_time =
        !           114:         pit_get_next_transition_time(sc, sc->count_load_time);
        !           115: }
        !           116: 
        !           117: static void kvm_pit_put(PITCommonState *s)
        !           118: {
        !           119:     struct kvm_pit_state2 kpit;
        !           120:     struct kvm_pit_channel_state *kchan;
        !           121:     struct PITChannelState *sc;
        !           122:     int i, ret;
        !           123: 
        !           124:     kpit.flags = s->channels[0].irq_disabled ? KVM_PIT_FLAGS_HPET_LEGACY : 0;
        !           125:     for (i = 0; i < 3; i++) {
        !           126:         kchan = &kpit.channels[i];
        !           127:         sc = &s->channels[i];
        !           128:         kchan->count = sc->count;
        !           129:         kchan->latched_count = sc->latched_count;
        !           130:         kchan->count_latched = sc->count_latched;
        !           131:         kchan->status_latched = sc->status_latched;
        !           132:         kchan->status = sc->status;
        !           133:         kchan->read_state = sc->read_state;
        !           134:         kchan->write_state = sc->write_state;
        !           135:         kchan->write_latch = sc->write_latch;
        !           136:         kchan->rw_mode = sc->rw_mode;
        !           137:         kchan->mode = sc->mode;
        !           138:         kchan->bcd = sc->bcd;
        !           139:         kchan->gate = sc->gate;
        !           140:         kchan->count_load_time = sc->count_load_time;
        !           141:     }
        !           142: 
        !           143:     ret = kvm_vm_ioctl(kvm_state,
        !           144:                        kvm_has_pit_state2() ? KVM_SET_PIT2 : KVM_SET_PIT,
        !           145:                        &kpit);
        !           146:     if (ret < 0) {
        !           147:         fprintf(stderr, "%s failed: %s\n",
        !           148:                 kvm_has_pit_state2() ? "KVM_SET_PIT2" : "KVM_SET_PIT",
        !           149:                 strerror(ret));
        !           150:         abort();
        !           151:     }
        !           152: }
        !           153: 
        !           154: static void kvm_pit_set_gate(PITCommonState *s, PITChannelState *sc, int val)
        !           155: {
        !           156:     kvm_pit_get(s);
        !           157: 
        !           158:     switch (sc->mode) {
        !           159:     default:
        !           160:     case 0:
        !           161:     case 4:
        !           162:         /* XXX: just disable/enable counting */
        !           163:         break;
        !           164:     case 1:
        !           165:     case 2:
        !           166:     case 3:
        !           167:     case 5:
        !           168:         if (sc->gate < val) {
        !           169:             /* restart counting on rising edge */
        !           170:             sc->count_load_time = qemu_get_clock_ns(vm_clock);
        !           171:         }
        !           172:         break;
        !           173:     }
        !           174:     sc->gate = val;
        !           175: 
        !           176:     kvm_pit_put(s);
        !           177: }
        !           178: 
        !           179: static void kvm_pit_get_channel_info(PITCommonState *s, PITChannelState *sc,
        !           180:                                      PITChannelInfo *info)
        !           181: {
        !           182:     kvm_pit_get(s);
        !           183: 
        !           184:     pit_get_channel_info_common(s, sc, info);
        !           185: }
        !           186: 
        !           187: static void kvm_pit_reset(DeviceState *dev)
        !           188: {
        !           189:     PITCommonState *s = DO_UPCAST(PITCommonState, dev.qdev, dev);
        !           190: 
        !           191:     pit_reset_common(s);
        !           192: 
        !           193:     kvm_pit_put(s);
        !           194: }
        !           195: 
        !           196: static void kvm_pit_irq_control(void *opaque, int n, int enable)
        !           197: {
        !           198:     PITCommonState *pit = opaque;
        !           199:     PITChannelState *s = &pit->channels[0];
        !           200: 
        !           201:     kvm_pit_get(pit);
        !           202: 
        !           203:     s->irq_disabled = !enable;
        !           204: 
        !           205:     kvm_pit_put(pit);
        !           206: }
        !           207: 
        !           208: static void kvm_pit_vm_state_change(void *opaque, int running,
        !           209:                                     RunState state)
        !           210: {
        !           211:     KVMPITState *s = opaque;
        !           212: 
        !           213:     if (running) {
        !           214:         s->state_valid = false;
        !           215:     } else {
        !           216:         kvm_pit_get(&s->pit);
        !           217:         s->state_valid = true;
        !           218:     }
        !           219: }
        !           220: 
        !           221: static int kvm_pit_initfn(PITCommonState *pit)
        !           222: {
        !           223:     KVMPITState *s = DO_UPCAST(KVMPITState, pit, pit);
        !           224:     struct kvm_pit_config config = {
        !           225:         .flags = 0,
        !           226:     };
        !           227:     int ret;
        !           228: 
        !           229:     if (kvm_check_extension(kvm_state, KVM_CAP_PIT2)) {
        !           230:         ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT2, &config);
        !           231:     } else {
        !           232:         ret = kvm_vm_ioctl(kvm_state, KVM_CREATE_PIT);
        !           233:     }
        !           234:     if (ret < 0) {
        !           235:         fprintf(stderr, "Create kernel PIC irqchip failed: %s\n",
        !           236:                 strerror(ret));
        !           237:         return ret;
        !           238:     }
        !           239:     switch (s->lost_tick_policy) {
        !           240:     case LOST_TICK_DELAY:
        !           241:         break; /* enabled by default */
        !           242:     case LOST_TICK_DISCARD:
        !           243:         if (kvm_check_extension(kvm_state, KVM_CAP_REINJECT_CONTROL)) {
        !           244:             struct kvm_reinject_control control = { .pit_reinject = 0 };
        !           245: 
        !           246:             ret = kvm_vm_ioctl(kvm_state, KVM_REINJECT_CONTROL, &control);
        !           247:             if (ret < 0) {
        !           248:                 fprintf(stderr,
        !           249:                         "Can't disable in-kernel PIT reinjection: %s\n",
        !           250:                         strerror(ret));
        !           251:                 return ret;
        !           252:             }
        !           253:         }
        !           254:         break;
        !           255:     default:
        !           256:         return -EINVAL;
        !           257:     }
        !           258: 
        !           259:     memory_region_init_reservation(&pit->ioports, "kvm-pit", 4);
        !           260: 
        !           261:     qdev_init_gpio_in(&pit->dev.qdev, kvm_pit_irq_control, 1);
        !           262: 
        !           263:     qemu_add_vm_change_state_handler(kvm_pit_vm_state_change, s);
        !           264: 
        !           265:     return 0;
        !           266: }
        !           267: 
        !           268: static Property kvm_pit_properties[] = {
        !           269:     DEFINE_PROP_HEX32("iobase", KVMPITState, pit.iobase,  -1),
        !           270:     DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", KVMPITState,
        !           271:                                lost_tick_policy, LOST_TICK_DELAY),
        !           272:     DEFINE_PROP_END_OF_LIST(),
        !           273: };
        !           274: 
        !           275: static void kvm_pit_class_init(ObjectClass *klass, void *data)
        !           276: {
        !           277:     PITCommonClass *k = PIT_COMMON_CLASS(klass);
        !           278:     DeviceClass *dc = DEVICE_CLASS(klass);
        !           279: 
        !           280:     k->init = kvm_pit_initfn;
        !           281:     k->set_channel_gate = kvm_pit_set_gate;
        !           282:     k->get_channel_info = kvm_pit_get_channel_info;
        !           283:     k->pre_save = kvm_pit_get;
        !           284:     k->post_load = kvm_pit_put;
        !           285:     dc->reset = kvm_pit_reset;
        !           286:     dc->props = kvm_pit_properties;
        !           287: }
        !           288: 
        !           289: static TypeInfo kvm_pit_info = {
        !           290:     .name          = "kvm-pit",
        !           291:     .parent        = TYPE_PIT_COMMON,
        !           292:     .instance_size = sizeof(KVMPITState),
        !           293:     .class_init = kvm_pit_class_init,
        !           294: };
        !           295: 
        !           296: static void kvm_pit_register(void)
        !           297: {
        !           298:     type_register_static(&kvm_pit_info);
        !           299: }
        !           300: 
        !           301: type_init(kvm_pit_register)

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