Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 1 | /* |
| 2 | * CPU thread main loop - common bits for user and system mode emulation |
| 3 | * |
| 4 | * Copyright (c) 2003-2005 Fabrice Bellard |
| 5 | * |
| 6 | * This library is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU Lesser General Public |
| 8 | * License as published by the Free Software Foundation; either |
Chetan Pant | d6ea423 | 2020-10-23 12:33:53 +0000 | [diff] [blame] | 9 | * version 2.1 of the License, or (at your option) any later version. |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 10 | * |
| 11 | * This library is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | * Lesser General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Lesser General Public |
| 17 | * License along with this library; if not, see <http://www.gnu.org/licenses/>. |
| 18 | */ |
| 19 | |
| 20 | #include "qemu/osdep.h" |
Paolo Bonzini | 53f5ed9 | 2016-08-28 05:38:24 +0200 | [diff] [blame] | 21 | #include "qemu/main-loop.h" |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 22 | #include "exec/cpu-common.h" |
Markus Armbruster | 2e5b09f | 2019-07-09 17:20:52 +0200 | [diff] [blame] | 23 | #include "hw/core/cpu.h" |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 24 | #include "sysemu/cpus.h" |
Daniel Brodsky | 6e8a355 | 2020-04-03 21:21:08 -0700 | [diff] [blame] | 25 | #include "qemu/lockable.h" |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 26 | |
| 27 | static QemuMutex qemu_cpu_list_lock; |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 28 | static QemuCond exclusive_cond; |
| 29 | static QemuCond exclusive_resume; |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 30 | static QemuCond qemu_work_cond; |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 31 | |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 32 | /* >= 1 if a thread is inside start_exclusive/end_exclusive. Written |
| 33 | * under qemu_cpu_list_lock, read with atomic operations. |
| 34 | */ |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 35 | static int pending_cpus; |
| 36 | |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 37 | void qemu_init_cpu_list(void) |
| 38 | { |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 39 | /* This is needed because qemu_init_cpu_list is also called by the |
| 40 | * child process in a fork. */ |
| 41 | pending_cpus = 0; |
| 42 | |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 43 | qemu_mutex_init(&qemu_cpu_list_lock); |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 44 | qemu_cond_init(&exclusive_cond); |
| 45 | qemu_cond_init(&exclusive_resume); |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 46 | qemu_cond_init(&qemu_work_cond); |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 47 | } |
| 48 | |
| 49 | void cpu_list_lock(void) |
| 50 | { |
| 51 | qemu_mutex_lock(&qemu_cpu_list_lock); |
| 52 | } |
| 53 | |
| 54 | void cpu_list_unlock(void) |
| 55 | { |
| 56 | qemu_mutex_unlock(&qemu_cpu_list_lock); |
| 57 | } |
| 58 | |
| 59 | static bool cpu_index_auto_assigned; |
| 60 | |
| 61 | static int cpu_get_free_index(void) |
| 62 | { |
| 63 | CPUState *some_cpu; |
Alex Bennée | 716386e | 2020-05-20 15:05:38 +0100 | [diff] [blame] | 64 | int max_cpu_index = 0; |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 65 | |
| 66 | cpu_index_auto_assigned = true; |
| 67 | CPU_FOREACH(some_cpu) { |
Alex Bennée | 716386e | 2020-05-20 15:05:38 +0100 | [diff] [blame] | 68 | if (some_cpu->cpu_index >= max_cpu_index) { |
| 69 | max_cpu_index = some_cpu->cpu_index + 1; |
| 70 | } |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 71 | } |
Alex Bennée | 716386e | 2020-05-20 15:05:38 +0100 | [diff] [blame] | 72 | return max_cpu_index; |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 73 | } |
| 74 | |
Philippe Mathieu-Daudé | 421a75e | 2020-07-02 12:40:17 +0200 | [diff] [blame] | 75 | CPUTailQ cpus = QTAILQ_HEAD_INITIALIZER(cpus); |
Hyman Huang(黄勇) | ab1a161 | 2022-06-26 01:38:31 +0800 | [diff] [blame] | 76 | static unsigned int cpu_list_generation_id; |
| 77 | |
| 78 | unsigned int cpu_list_generation_id_get(void) |
| 79 | { |
| 80 | return cpu_list_generation_id; |
| 81 | } |
Philippe Mathieu-Daudé | 421a75e | 2020-07-02 12:40:17 +0200 | [diff] [blame] | 82 | |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 83 | void cpu_list_add(CPUState *cpu) |
| 84 | { |
Daniel Brodsky | 6e8a355 | 2020-04-03 21:21:08 -0700 | [diff] [blame] | 85 | QEMU_LOCK_GUARD(&qemu_cpu_list_lock); |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 86 | if (cpu->cpu_index == UNASSIGNED_CPU_INDEX) { |
| 87 | cpu->cpu_index = cpu_get_free_index(); |
| 88 | assert(cpu->cpu_index != UNASSIGNED_CPU_INDEX); |
| 89 | } else { |
| 90 | assert(!cpu_index_auto_assigned); |
| 91 | } |
Emilio G. Cota | 068a5ea | 2018-08-19 05:13:35 -0400 | [diff] [blame] | 92 | QTAILQ_INSERT_TAIL_RCU(&cpus, cpu, node); |
Hyman Huang(黄勇) | ab1a161 | 2022-06-26 01:38:31 +0800 | [diff] [blame] | 93 | cpu_list_generation_id++; |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 94 | } |
| 95 | |
| 96 | void cpu_list_remove(CPUState *cpu) |
| 97 | { |
Daniel Brodsky | 6e8a355 | 2020-04-03 21:21:08 -0700 | [diff] [blame] | 98 | QEMU_LOCK_GUARD(&qemu_cpu_list_lock); |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 99 | if (!QTAILQ_IN_USE(cpu, node)) { |
| 100 | /* there is nothing to undo since cpu_exec_init() hasn't been called */ |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 101 | return; |
| 102 | } |
| 103 | |
Emilio G. Cota | 068a5ea | 2018-08-19 05:13:35 -0400 | [diff] [blame] | 104 | QTAILQ_REMOVE_RCU(&cpus, cpu, node); |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 105 | cpu->cpu_index = UNASSIGNED_CPU_INDEX; |
Hyman Huang(黄勇) | ab1a161 | 2022-06-26 01:38:31 +0800 | [diff] [blame] | 106 | cpu_list_generation_id++; |
Paolo Bonzini | 267f685 | 2016-08-28 03:45:14 +0200 | [diff] [blame] | 107 | } |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 108 | |
Philippe Mathieu-Daudé | 421a75e | 2020-07-02 12:40:17 +0200 | [diff] [blame] | 109 | CPUState *qemu_get_cpu(int index) |
| 110 | { |
| 111 | CPUState *cpu; |
| 112 | |
| 113 | CPU_FOREACH(cpu) { |
| 114 | if (cpu->cpu_index == index) { |
| 115 | return cpu; |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | return NULL; |
| 120 | } |
| 121 | |
| 122 | /* current CPU in the current thread. It is only valid inside cpu_exec() */ |
| 123 | __thread CPUState *current_cpu; |
| 124 | |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 125 | struct qemu_work_item { |
Emilio G. Cota | 0c0fcc2 | 2020-06-12 20:02:24 +0100 | [diff] [blame] | 126 | QSIMPLEQ_ENTRY(qemu_work_item) node; |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 127 | run_on_cpu_func func; |
Paolo Bonzini | 14e6fe1 | 2016-10-31 10:36:08 +0100 | [diff] [blame] | 128 | run_on_cpu_data data; |
Paolo Bonzini | 53f5ed9 | 2016-08-28 05:38:24 +0200 | [diff] [blame] | 129 | bool free, exclusive, done; |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 130 | }; |
| 131 | |
| 132 | static void queue_work_on_cpu(CPUState *cpu, struct qemu_work_item *wi) |
| 133 | { |
| 134 | qemu_mutex_lock(&cpu->work_mutex); |
Emilio G. Cota | 0c0fcc2 | 2020-06-12 20:02:24 +0100 | [diff] [blame] | 135 | QSIMPLEQ_INSERT_TAIL(&cpu->work_list, wi, node); |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 136 | wi->done = false; |
| 137 | qemu_mutex_unlock(&cpu->work_mutex); |
| 138 | |
| 139 | qemu_cpu_kick(cpu); |
| 140 | } |
| 141 | |
Paolo Bonzini | 14e6fe1 | 2016-10-31 10:36:08 +0100 | [diff] [blame] | 142 | void do_run_on_cpu(CPUState *cpu, run_on_cpu_func func, run_on_cpu_data data, |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 143 | QemuMutex *mutex) |
| 144 | { |
| 145 | struct qemu_work_item wi; |
| 146 | |
| 147 | if (qemu_cpu_is_self(cpu)) { |
| 148 | func(cpu, data); |
| 149 | return; |
| 150 | } |
| 151 | |
| 152 | wi.func = func; |
| 153 | wi.data = data; |
Paolo Bonzini | 0e55539 | 2016-09-06 17:28:03 +0200 | [diff] [blame] | 154 | wi.done = false; |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 155 | wi.free = false; |
Paolo Bonzini | 53f5ed9 | 2016-08-28 05:38:24 +0200 | [diff] [blame] | 156 | wi.exclusive = false; |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 157 | |
| 158 | queue_work_on_cpu(cpu, &wi); |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 159 | while (!qatomic_mb_read(&wi.done)) { |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 160 | CPUState *self_cpu = current_cpu; |
| 161 | |
| 162 | qemu_cond_wait(&qemu_work_cond, mutex); |
| 163 | current_cpu = self_cpu; |
| 164 | } |
| 165 | } |
| 166 | |
Paolo Bonzini | 14e6fe1 | 2016-10-31 10:36:08 +0100 | [diff] [blame] | 167 | void async_run_on_cpu(CPUState *cpu, run_on_cpu_func func, run_on_cpu_data data) |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 168 | { |
| 169 | struct qemu_work_item *wi; |
| 170 | |
Markus Armbruster | b21e238 | 2022-03-15 15:41:56 +0100 | [diff] [blame] | 171 | wi = g_new0(struct qemu_work_item, 1); |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 172 | wi->func = func; |
| 173 | wi->data = data; |
| 174 | wi->free = true; |
| 175 | |
| 176 | queue_work_on_cpu(cpu, wi); |
| 177 | } |
| 178 | |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 179 | /* Wait for pending exclusive operations to complete. The CPU list lock |
| 180 | must be held. */ |
| 181 | static inline void exclusive_idle(void) |
| 182 | { |
| 183 | while (pending_cpus) { |
| 184 | qemu_cond_wait(&exclusive_resume, &qemu_cpu_list_lock); |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | /* Start an exclusive operation. |
Paolo Bonzini | 758e1b2 | 2016-09-02 23:33:38 +0200 | [diff] [blame] | 189 | Must only be called from outside cpu_exec. */ |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 190 | void start_exclusive(void) |
| 191 | { |
| 192 | CPUState *other_cpu; |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 193 | int running_cpus; |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 194 | |
| 195 | qemu_mutex_lock(&qemu_cpu_list_lock); |
| 196 | exclusive_idle(); |
| 197 | |
| 198 | /* Make all other cpus stop executing. */ |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 199 | qatomic_set(&pending_cpus, 1); |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 200 | |
| 201 | /* Write pending_cpus before reading other_cpu->running. */ |
| 202 | smp_mb(); |
| 203 | running_cpus = 0; |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 204 | CPU_FOREACH(other_cpu) { |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 205 | if (qatomic_read(&other_cpu->running)) { |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 206 | other_cpu->has_waiter = true; |
| 207 | running_cpus++; |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 208 | qemu_cpu_kick(other_cpu); |
| 209 | } |
| 210 | } |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 211 | |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 212 | qatomic_set(&pending_cpus, running_cpus + 1); |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 213 | while (pending_cpus > 1) { |
| 214 | qemu_cond_wait(&exclusive_cond, &qemu_cpu_list_lock); |
| 215 | } |
Paolo Bonzini | 758e1b2 | 2016-09-02 23:33:38 +0200 | [diff] [blame] | 216 | |
| 217 | /* Can release mutex, no one will enter another exclusive |
| 218 | * section until end_exclusive resets pending_cpus to 0. |
| 219 | */ |
| 220 | qemu_mutex_unlock(&qemu_cpu_list_lock); |
Emilio G. Cota | cfbc3c6 | 2018-11-26 17:14:43 -0500 | [diff] [blame] | 221 | |
| 222 | current_cpu->in_exclusive_context = true; |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 223 | } |
| 224 | |
Paolo Bonzini | 758e1b2 | 2016-09-02 23:33:38 +0200 | [diff] [blame] | 225 | /* Finish an exclusive operation. */ |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 226 | void end_exclusive(void) |
| 227 | { |
Emilio G. Cota | cfbc3c6 | 2018-11-26 17:14:43 -0500 | [diff] [blame] | 228 | current_cpu->in_exclusive_context = false; |
| 229 | |
Paolo Bonzini | 758e1b2 | 2016-09-02 23:33:38 +0200 | [diff] [blame] | 230 | qemu_mutex_lock(&qemu_cpu_list_lock); |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 231 | qatomic_set(&pending_cpus, 0); |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 232 | qemu_cond_broadcast(&exclusive_resume); |
| 233 | qemu_mutex_unlock(&qemu_cpu_list_lock); |
| 234 | } |
| 235 | |
| 236 | /* Wait for exclusive ops to finish, and begin cpu execution. */ |
| 237 | void cpu_exec_start(CPUState *cpu) |
| 238 | { |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 239 | qatomic_set(&cpu->running, true); |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 240 | |
| 241 | /* Write cpu->running before reading pending_cpus. */ |
| 242 | smp_mb(); |
| 243 | |
| 244 | /* 1. start_exclusive saw cpu->running == true and pending_cpus >= 1. |
| 245 | * After taking the lock we'll see cpu->has_waiter == true and run---not |
| 246 | * for long because start_exclusive kicked us. cpu_exec_end will |
| 247 | * decrement pending_cpus and signal the waiter. |
| 248 | * |
| 249 | * 2. start_exclusive saw cpu->running == false but pending_cpus >= 1. |
| 250 | * This includes the case when an exclusive item is running now. |
| 251 | * Then we'll see cpu->has_waiter == false and wait for the item to |
| 252 | * complete. |
| 253 | * |
| 254 | * 3. pending_cpus == 0. Then start_exclusive is definitely going to |
| 255 | * see cpu->running == true, and it will kick the CPU. |
| 256 | */ |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 257 | if (unlikely(qatomic_read(&pending_cpus))) { |
Daniel Brodsky | 6e8a355 | 2020-04-03 21:21:08 -0700 | [diff] [blame] | 258 | QEMU_LOCK_GUARD(&qemu_cpu_list_lock); |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 259 | if (!cpu->has_waiter) { |
| 260 | /* Not counted in pending_cpus, let the exclusive item |
| 261 | * run. Since we have the lock, just set cpu->running to true |
| 262 | * while holding it; no need to check pending_cpus again. |
| 263 | */ |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 264 | qatomic_set(&cpu->running, false); |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 265 | exclusive_idle(); |
| 266 | /* Now pending_cpus is zero. */ |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 267 | qatomic_set(&cpu->running, true); |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 268 | } else { |
| 269 | /* Counted in pending_cpus, go ahead and release the |
| 270 | * waiter at cpu_exec_end. |
| 271 | */ |
| 272 | } |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 273 | } |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 274 | } |
| 275 | |
| 276 | /* Mark cpu as not executing, and release pending exclusive ops. */ |
| 277 | void cpu_exec_end(CPUState *cpu) |
| 278 | { |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 279 | qatomic_set(&cpu->running, false); |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 280 | |
| 281 | /* Write cpu->running before reading pending_cpus. */ |
| 282 | smp_mb(); |
| 283 | |
| 284 | /* 1. start_exclusive saw cpu->running == true. Then it will increment |
| 285 | * pending_cpus and wait for exclusive_cond. After taking the lock |
| 286 | * we'll see cpu->has_waiter == true. |
| 287 | * |
| 288 | * 2. start_exclusive saw cpu->running == false but here pending_cpus >= 1. |
| 289 | * This includes the case when an exclusive item started after setting |
| 290 | * cpu->running to false and before we read pending_cpus. Then we'll see |
| 291 | * cpu->has_waiter == false and not touch pending_cpus. The next call to |
| 292 | * cpu_exec_start will run exclusive_idle if still necessary, thus waiting |
| 293 | * for the item to complete. |
| 294 | * |
| 295 | * 3. pending_cpus == 0. Then start_exclusive is definitely going to |
| 296 | * see cpu->running == false, and it can ignore this CPU until the |
| 297 | * next cpu_exec_start. |
| 298 | */ |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 299 | if (unlikely(qatomic_read(&pending_cpus))) { |
Daniel Brodsky | 6e8a355 | 2020-04-03 21:21:08 -0700 | [diff] [blame] | 300 | QEMU_LOCK_GUARD(&qemu_cpu_list_lock); |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 301 | if (cpu->has_waiter) { |
| 302 | cpu->has_waiter = false; |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 303 | qatomic_set(&pending_cpus, pending_cpus - 1); |
Paolo Bonzini | c265e97 | 2016-08-31 21:33:58 +0200 | [diff] [blame] | 304 | if (pending_cpus == 1) { |
| 305 | qemu_cond_signal(&exclusive_cond); |
| 306 | } |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 307 | } |
| 308 | } |
Paolo Bonzini | ab12997 | 2016-08-31 16:56:04 +0200 | [diff] [blame] | 309 | } |
| 310 | |
Paolo Bonzini | 14e6fe1 | 2016-10-31 10:36:08 +0100 | [diff] [blame] | 311 | void async_safe_run_on_cpu(CPUState *cpu, run_on_cpu_func func, |
| 312 | run_on_cpu_data data) |
Paolo Bonzini | 53f5ed9 | 2016-08-28 05:38:24 +0200 | [diff] [blame] | 313 | { |
| 314 | struct qemu_work_item *wi; |
| 315 | |
Markus Armbruster | b21e238 | 2022-03-15 15:41:56 +0100 | [diff] [blame] | 316 | wi = g_new0(struct qemu_work_item, 1); |
Paolo Bonzini | 53f5ed9 | 2016-08-28 05:38:24 +0200 | [diff] [blame] | 317 | wi->func = func; |
| 318 | wi->data = data; |
| 319 | wi->free = true; |
| 320 | wi->exclusive = true; |
| 321 | |
| 322 | queue_work_on_cpu(cpu, wi); |
| 323 | } |
| 324 | |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 325 | void process_queued_cpu_work(CPUState *cpu) |
| 326 | { |
| 327 | struct qemu_work_item *wi; |
| 328 | |
Emilio G. Cota | 0c0fcc2 | 2020-06-12 20:02:24 +0100 | [diff] [blame] | 329 | qemu_mutex_lock(&cpu->work_mutex); |
| 330 | if (QSIMPLEQ_EMPTY(&cpu->work_list)) { |
| 331 | qemu_mutex_unlock(&cpu->work_mutex); |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 332 | return; |
| 333 | } |
Emilio G. Cota | 0c0fcc2 | 2020-06-12 20:02:24 +0100 | [diff] [blame] | 334 | while (!QSIMPLEQ_EMPTY(&cpu->work_list)) { |
| 335 | wi = QSIMPLEQ_FIRST(&cpu->work_list); |
| 336 | QSIMPLEQ_REMOVE_HEAD(&cpu->work_list, node); |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 337 | qemu_mutex_unlock(&cpu->work_mutex); |
Paolo Bonzini | 53f5ed9 | 2016-08-28 05:38:24 +0200 | [diff] [blame] | 338 | if (wi->exclusive) { |
| 339 | /* Running work items outside the BQL avoids the following deadlock: |
| 340 | * 1) start_exclusive() is called with the BQL taken while another |
| 341 | * CPU is running; 2) cpu_exec in the other CPU tries to takes the |
| 342 | * BQL, so it goes to sleep; start_exclusive() is sleeping too, so |
| 343 | * neither CPU can proceed. |
| 344 | */ |
| 345 | qemu_mutex_unlock_iothread(); |
| 346 | start_exclusive(); |
| 347 | wi->func(cpu, wi->data); |
| 348 | end_exclusive(); |
| 349 | qemu_mutex_lock_iothread(); |
| 350 | } else { |
| 351 | wi->func(cpu, wi->data); |
| 352 | } |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 353 | qemu_mutex_lock(&cpu->work_mutex); |
| 354 | if (wi->free) { |
| 355 | g_free(wi); |
| 356 | } else { |
Stefan Hajnoczi | d73415a | 2020-09-23 11:56:46 +0100 | [diff] [blame] | 357 | qatomic_mb_set(&wi->done, true); |
Sergey Fedorov | d148d90 | 2016-08-29 09:51:00 +0200 | [diff] [blame] | 358 | } |
| 359 | } |
| 360 | qemu_mutex_unlock(&cpu->work_mutex); |
| 361 | qemu_cond_broadcast(&qemu_work_cond); |
| 362 | } |