| 1 | /* |
| 2 | * QEMU System Emulator |
| 3 | * |
| 4 | * Copyright (c) 2003-2008 Fabrice Bellard |
| 5 | * |
| 6 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 7 | * of this software and associated documentation files (the "Software"), to deal |
| 8 | * in the Software without restriction, including without limitation the rights |
| 9 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 10 | * copies of the Software, and to permit persons to whom the Software is |
| 11 | * furnished to do so, subject to the following conditions: |
| 12 | * |
| 13 | * The above copyright notice and this permission notice shall be included in |
| 14 | * all copies or substantial portions of the Software. |
| 15 | * |
| 16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| 19 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| 22 | * THE SOFTWARE. |
| 23 | */ |
| 24 | |
| 25 | #include "qemu/osdep.h" |
| 26 | #include "qemu/cutils.h" |
| 27 | #include "migration/vmstate.h" |
| 28 | #include "qapi/error.h" |
| 29 | #include "qemu/error-report.h" |
| 30 | #include "system/cpus.h" |
| 31 | #include "qemu/main-loop.h" |
| 32 | #include "qemu/option.h" |
| 33 | #include "qemu/seqlock.h" |
| 34 | #include "system/replay.h" |
| 35 | #include "system/runstate.h" |
| 36 | #include "hw/core/cpu.h" |
| 37 | #include "system/cpu-timers.h" |
| 38 | #include "system/cpu-timers-internal.h" |
| 39 | #include "exec/icount.h" |
| 40 | |
| 41 | /* clock and ticks */ |
| 42 | |
| 43 | static int64_t cpu_get_ticks_locked(void) |
| 44 | { |
| 45 | int64_t ticks = timers_state.cpu_ticks_offset; |
| 46 | if (timers_state.cpu_ticks_enabled) { |
| 47 | ticks += cpu_get_host_ticks(); |
| 48 | } |
| 49 | |
| 50 | if (timers_state.cpu_ticks_prev > ticks) { |
| 51 | /* Non increasing ticks may happen if the host uses software suspend. */ |
| 52 | timers_state.cpu_ticks_offset += timers_state.cpu_ticks_prev - ticks; |
| 53 | ticks = timers_state.cpu_ticks_prev; |
| 54 | } |
| 55 | |
| 56 | timers_state.cpu_ticks_prev = ticks; |
| 57 | return ticks; |
| 58 | } |
| 59 | |
| 60 | /* |
| 61 | * return the time elapsed in VM between vm_start and vm_stop. |
| 62 | * cpu_get_ticks() uses units of the host CPU cycle counter. |
| 63 | */ |
| 64 | int64_t cpu_get_ticks(void) |
| 65 | { |
| 66 | int64_t ticks; |
| 67 | |
| 68 | qemu_spin_lock(&timers_state.vm_clock_lock); |
| 69 | ticks = cpu_get_ticks_locked(); |
| 70 | qemu_spin_unlock(&timers_state.vm_clock_lock); |
| 71 | return ticks; |
| 72 | } |
| 73 | |
| 74 | int64_t cpu_get_clock_locked(void) |
| 75 | { |
| 76 | int64_t time; |
| 77 | |
| 78 | time = timers_state.cpu_clock_offset; |
| 79 | if (timers_state.cpu_ticks_enabled) { |
| 80 | time += get_clock(); |
| 81 | } |
| 82 | |
| 83 | return time; |
| 84 | } |
| 85 | |
| 86 | /* |
| 87 | * Return the monotonic time elapsed in VM, i.e., |
| 88 | * the time between vm_start and vm_stop |
| 89 | */ |
| 90 | int64_t cpu_get_clock(void) |
| 91 | { |
| 92 | int64_t ti; |
| 93 | unsigned start; |
| 94 | |
| 95 | do { |
| 96 | start = seqlock_read_begin(&timers_state.vm_clock_seqlock); |
| 97 | ti = cpu_get_clock_locked(); |
| 98 | } while (seqlock_read_retry(&timers_state.vm_clock_seqlock, start)); |
| 99 | |
| 100 | return ti; |
| 101 | } |
| 102 | |
| 103 | /* |
| 104 | * enable cpu_get_ticks() |
| 105 | * Caller must hold BQL which serves as mutex for vm_clock_seqlock. |
| 106 | */ |
| 107 | void cpu_enable_ticks(void) |
| 108 | { |
| 109 | seqlock_write_lock(&timers_state.vm_clock_seqlock, |
| 110 | &timers_state.vm_clock_lock); |
| 111 | if (!timers_state.cpu_ticks_enabled) { |
| 112 | timers_state.cpu_ticks_offset -= cpu_get_host_ticks(); |
| 113 | timers_state.cpu_clock_offset -= get_clock(); |
| 114 | timers_state.cpu_ticks_enabled = 1; |
| 115 | } |
| 116 | seqlock_write_unlock(&timers_state.vm_clock_seqlock, |
| 117 | &timers_state.vm_clock_lock); |
| 118 | } |
| 119 | |
| 120 | /* |
| 121 | * disable cpu_get_ticks() : the clock is stopped. You must not call |
| 122 | * cpu_get_ticks() after that. |
| 123 | * Caller must hold BQL which serves as mutex for vm_clock_seqlock. |
| 124 | */ |
| 125 | void cpu_disable_ticks(void) |
| 126 | { |
| 127 | seqlock_write_lock(&timers_state.vm_clock_seqlock, |
| 128 | &timers_state.vm_clock_lock); |
| 129 | if (timers_state.cpu_ticks_enabled) { |
| 130 | timers_state.cpu_ticks_offset += cpu_get_host_ticks(); |
| 131 | timers_state.cpu_clock_offset = cpu_get_clock_locked(); |
| 132 | timers_state.cpu_ticks_enabled = 0; |
| 133 | } |
| 134 | seqlock_write_unlock(&timers_state.vm_clock_seqlock, |
| 135 | &timers_state.vm_clock_lock); |
| 136 | } |
| 137 | |
| 138 | static bool icount_state_needed(void *opaque) |
| 139 | { |
| 140 | return icount_enabled(); |
| 141 | } |
| 142 | |
| 143 | static bool warp_timer_state_needed(void *opaque) |
| 144 | { |
| 145 | TimersState *s = opaque; |
| 146 | return s->icount_warp_timer != NULL; |
| 147 | } |
| 148 | |
| 149 | static bool adjust_timers_state_needed(void *opaque) |
| 150 | { |
| 151 | TimersState *s = opaque; |
| 152 | return s->icount_rt_timer != NULL; |
| 153 | } |
| 154 | |
| 155 | static bool icount_shift_state_needed(void *opaque) |
| 156 | { |
| 157 | return icount_enabled() == ICOUNT_ADAPTATIVE; |
| 158 | } |
| 159 | |
| 160 | /* |
| 161 | * Subsection for warp timer migration is optional, because may not be created |
| 162 | */ |
| 163 | static const VMStateDescription icount_vmstate_warp_timer = { |
| 164 | .name = "timer/icount/warp_timer", |
| 165 | .version_id = 1, |
| 166 | .minimum_version_id = 1, |
| 167 | .needed = warp_timer_state_needed, |
| 168 | .fields = (const VMStateField[]) { |
| 169 | VMSTATE_INT64(vm_clock_warp_start, TimersState), |
| 170 | VMSTATE_TIMER_PTR(icount_warp_timer, TimersState), |
| 171 | VMSTATE_END_OF_LIST() |
| 172 | } |
| 173 | }; |
| 174 | |
| 175 | static const VMStateDescription icount_vmstate_adjust_timers = { |
| 176 | .name = "timer/icount/timers", |
| 177 | .version_id = 1, |
| 178 | .minimum_version_id = 1, |
| 179 | .needed = adjust_timers_state_needed, |
| 180 | .fields = (const VMStateField[]) { |
| 181 | VMSTATE_TIMER_PTR(icount_rt_timer, TimersState), |
| 182 | VMSTATE_TIMER_PTR(icount_vm_timer, TimersState), |
| 183 | VMSTATE_END_OF_LIST() |
| 184 | } |
| 185 | }; |
| 186 | |
| 187 | static const VMStateDescription icount_vmstate_shift = { |
| 188 | .name = "timer/icount/shift", |
| 189 | .version_id = 2, |
| 190 | .minimum_version_id = 2, |
| 191 | .needed = icount_shift_state_needed, |
| 192 | .fields = (const VMStateField[]) { |
| 193 | VMSTATE_INT16(icount_time_shift, TimersState), |
| 194 | VMSTATE_INT64(last_delta, TimersState), |
| 195 | VMSTATE_END_OF_LIST() |
| 196 | } |
| 197 | }; |
| 198 | |
| 199 | /* |
| 200 | * This is a subsection for icount migration. |
| 201 | */ |
| 202 | static const VMStateDescription icount_vmstate_timers = { |
| 203 | .name = "timer/icount", |
| 204 | .version_id = 1, |
| 205 | .minimum_version_id = 1, |
| 206 | .needed = icount_state_needed, |
| 207 | .fields = (const VMStateField[]) { |
| 208 | VMSTATE_INT64(qemu_icount_bias, TimersState), |
| 209 | VMSTATE_INT64(qemu_icount, TimersState), |
| 210 | VMSTATE_END_OF_LIST() |
| 211 | }, |
| 212 | .subsections = (const VMStateDescription * const []) { |
| 213 | &icount_vmstate_warp_timer, |
| 214 | &icount_vmstate_adjust_timers, |
| 215 | &icount_vmstate_shift, |
| 216 | NULL |
| 217 | } |
| 218 | }; |
| 219 | |
| 220 | static const VMStateDescription vmstate_timers = { |
| 221 | .name = "timer", |
| 222 | .version_id = 2, |
| 223 | .minimum_version_id = 1, |
| 224 | .fields = (const VMStateField[]) { |
| 225 | VMSTATE_INT64(cpu_ticks_offset, TimersState), |
| 226 | VMSTATE_UNUSED(8), |
| 227 | VMSTATE_INT64_V(cpu_clock_offset, TimersState, 2), |
| 228 | VMSTATE_END_OF_LIST() |
| 229 | }, |
| 230 | .subsections = (const VMStateDescription * const []) { |
| 231 | &icount_vmstate_timers, |
| 232 | NULL |
| 233 | } |
| 234 | }; |
| 235 | |
| 236 | static void do_nothing(CPUState *cpu, run_on_cpu_data unused) |
| 237 | { |
| 238 | } |
| 239 | |
| 240 | void qemu_timer_notify_cb(void *opaque, QEMUClockType type) |
| 241 | { |
| 242 | if (!icount_enabled() || type != QEMU_CLOCK_VIRTUAL) { |
| 243 | qemu_notify_event(); |
| 244 | return; |
| 245 | } |
| 246 | |
| 247 | if (qemu_in_vcpu_thread()) { |
| 248 | /* |
| 249 | * A CPU is currently running; send it out of the |
| 250 | * tcg_cpu_exec() loop so it will recalculate its |
| 251 | * icount deadline immediately. |
| 252 | */ |
| 253 | cpu_exit(current_cpu); |
| 254 | } else if (first_cpu) { |
| 255 | /* |
| 256 | * cpu_exit() is not enough to kick a halted CPU out of |
| 257 | * qemu_tcg_wait_io_event. async_run_on_cpu, instead, |
| 258 | * causes cpu_thread_is_idle to return false. This way, |
| 259 | * handle_icount_deadline can run. |
| 260 | * If we have no CPUs at all for some reason, we don't |
| 261 | * need to do anything. |
| 262 | */ |
| 263 | async_run_on_cpu(first_cpu, do_nothing, RUN_ON_CPU_NULL); |
| 264 | } |
| 265 | } |
| 266 | |
| 267 | TimersState timers_state; |
| 268 | |
| 269 | /* initialize timers state and the cpu throttle for convenience */ |
| 270 | void cpu_timers_init(void) |
| 271 | { |
| 272 | seqlock_init(&timers_state.vm_clock_seqlock); |
| 273 | qemu_spin_init(&timers_state.vm_clock_lock); |
| 274 | vmstate_register(NULL, 0, &vmstate_timers, &timers_state); |
| 275 | } |