diff options
Diffstat (limited to 'system/cpus.c')
| -rw-r--r-- | system/cpus.c | 102 |
1 files changed, 67 insertions, 35 deletions
diff --git a/system/cpus.c b/system/cpus.c index a444a747f0..68d161d96b 100644 --- a/system/cpus.c +++ b/system/cpus.c @@ -65,7 +65,8 @@ #endif /* CONFIG_LINUX */ -static QemuMutex qemu_global_mutex; +/* The Big QEMU Lock (BQL) */ +static QemuMutex bql; /* * The chosen accelerator is supposed to register this. @@ -259,14 +260,33 @@ void cpu_interrupt(CPUState *cpu, int mask) } } +/* + * True if the vm was previously suspended, and has not been woken or reset. + */ +static int vm_was_suspended; + +void vm_set_suspended(bool suspended) +{ + vm_was_suspended = suspended; +} + +bool vm_get_suspended(void) +{ + return vm_was_suspended; +} + static int do_vm_stop(RunState state, bool send_stop) { int ret = 0; + RunState oldstate = runstate_get(); - if (runstate_is_running()) { + if (runstate_is_live(oldstate)) { + vm_was_suspended = (oldstate == RUN_STATE_SUSPENDED); runstate_set(state); cpu_disable_ticks(); - pause_all_vcpus(); + if (oldstate == RUN_STATE_RUNNING) { + pause_all_vcpus(); + } vm_state_notify(0, state); if (send_stop) { qapi_event_send_stop(); @@ -389,14 +409,14 @@ void qemu_init_cpu_loop(void) qemu_init_sigbus(); qemu_cond_init(&qemu_cpu_cond); qemu_cond_init(&qemu_pause_cond); - qemu_mutex_init(&qemu_global_mutex); + qemu_mutex_init(&bql); qemu_thread_get_self(&io_thread); } void run_on_cpu(CPUState *cpu, run_on_cpu_func func, run_on_cpu_data data) { - do_run_on_cpu(cpu, func, data, &qemu_global_mutex); + do_run_on_cpu(cpu, func, data, &bql); } static void qemu_cpu_stop(CPUState *cpu, bool exit) @@ -428,7 +448,7 @@ void qemu_wait_io_event(CPUState *cpu) slept = true; qemu_plugin_vcpu_idle_cb(cpu); } - qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex); + qemu_cond_wait(cpu->halt_cond, &bql); } if (slept) { qemu_plugin_vcpu_resume_cb(cpu); @@ -481,46 +501,46 @@ bool qemu_in_vcpu_thread(void) return current_cpu && qemu_cpu_is_self(current_cpu); } -QEMU_DEFINE_STATIC_CO_TLS(bool, iothread_locked) +QEMU_DEFINE_STATIC_CO_TLS(bool, bql_locked) -bool qemu_mutex_iothread_locked(void) +bool bql_locked(void) { - return get_iothread_locked(); + return get_bql_locked(); } bool qemu_in_main_thread(void) { - return qemu_mutex_iothread_locked(); + return bql_locked(); } /* * The BQL is taken from so many places that it is worth profiling the * callers directly, instead of funneling them all through a single function. */ -void qemu_mutex_lock_iothread_impl(const char *file, int line) +void bql_lock_impl(const char *file, int line) { - QemuMutexLockFunc bql_lock = qatomic_read(&qemu_bql_mutex_lock_func); + QemuMutexLockFunc bql_lock_fn = qatomic_read(&bql_mutex_lock_func); - g_assert(!qemu_mutex_iothread_locked()); - bql_lock(&qemu_global_mutex, file, line); - set_iothread_locked(true); + g_assert(!bql_locked()); + bql_lock_fn(&bql, file, line); + set_bql_locked(true); } -void qemu_mutex_unlock_iothread(void) +void bql_unlock(void) { - g_assert(qemu_mutex_iothread_locked()); - set_iothread_locked(false); - qemu_mutex_unlock(&qemu_global_mutex); + g_assert(bql_locked()); + set_bql_locked(false); + qemu_mutex_unlock(&bql); } -void qemu_cond_wait_iothread(QemuCond *cond) +void qemu_cond_wait_bql(QemuCond *cond) { - qemu_cond_wait(cond, &qemu_global_mutex); + qemu_cond_wait(cond, &bql); } -void qemu_cond_timedwait_iothread(QemuCond *cond, int ms) +void qemu_cond_timedwait_bql(QemuCond *cond, int ms) { - qemu_cond_timedwait(cond, &qemu_global_mutex, ms); + qemu_cond_timedwait(cond, &bql, ms); } /* signal CPU creation */ @@ -571,15 +591,15 @@ void pause_all_vcpus(void) replay_mutex_unlock(); while (!all_vcpus_paused()) { - qemu_cond_wait(&qemu_pause_cond, &qemu_global_mutex); + qemu_cond_wait(&qemu_pause_cond, &bql); CPU_FOREACH(cpu) { qemu_cpu_kick(cpu); } } - qemu_mutex_unlock_iothread(); + bql_unlock(); replay_mutex_lock(); - qemu_mutex_lock_iothread(); + bql_lock(); } void cpu_resume(CPUState *cpu) @@ -608,9 +628,9 @@ void cpu_remove_sync(CPUState *cpu) cpu->stop = true; cpu->unplug = true; qemu_cpu_kick(cpu); - qemu_mutex_unlock_iothread(); + bql_unlock(); qemu_thread_join(cpu->thread); - qemu_mutex_lock_iothread(); + bql_lock(); } void cpus_register_accel(const AccelOpsClass *ops) @@ -649,7 +669,7 @@ void qemu_init_vcpu(CPUState *cpu) cpus_accel->create_vcpu_thread(cpu); while (!cpu->created) { - qemu_cond_wait(&qemu_cpu_cond, &qemu_global_mutex); + qemu_cond_wait(&qemu_cpu_cond, &bql); } } @@ -679,11 +699,13 @@ int vm_stop(RunState state) /** * Prepare for (re)starting the VM. - * Returns -1 if the vCPUs are not to be restarted (e.g. if they are already - * running or in case of an error condition), 0 otherwise. + * Returns 0 if the vCPUs should be restarted, -1 on an error condition, + * and 1 otherwise. */ int vm_prepare_start(bool step_pending) { + int ret = vm_was_suspended ? 1 : 0; + RunState state = vm_was_suspended ? RUN_STATE_SUSPENDED : RUN_STATE_RUNNING; RunState requested; qemu_vmstop_requested(&requested); @@ -714,9 +736,10 @@ int vm_prepare_start(bool step_pending) qapi_event_send_resume(); cpu_enable_ticks(); - runstate_set(RUN_STATE_RUNNING); - vm_state_notify(1, RUN_STATE_RUNNING); - return 0; + runstate_set(state); + vm_state_notify(1, state); + vm_was_suspended = false; + return ret; } void vm_start(void) @@ -726,11 +749,20 @@ void vm_start(void) } } +void vm_resume(RunState state) +{ + if (runstate_is_live(state)) { + vm_start(); + } else { + runstate_set(state); + } +} + /* does a state transition even if the VM is already stopped, current state is forgotten forever */ int vm_stop_force_state(RunState state) { - if (runstate_is_running()) { + if (runstate_is_live(runstate_get())) { return vm_stop(state); } else { int ret; |