void qemu_event_set(QemuEvent *ev)
{
if (atomic_mb_read(&ev->value) != EV_SET) {
if (atomic_xchg(&ev->value, EV_SET) == EV_BUSY) {
/* There were waiters, wake them up. */
futex_wake(ev, INT_MAX);
}
}
}
void qemu_event_reset(QemuEvent *ev)
{
if (atomic_mb_read(&ev->value) == EV_SET) {
/*
* If there was a concurrent reset (or even reset+wait),
* do nothing. Otherwise change EV_SET->EV_FREE.
*/
atomic_or(&ev->value, EV_FREE);
}
}
void qemu_event_wait(QemuEvent *ev)
{
unsigned value;
value = atomic_mb_read(&ev->value);
if (value != EV_SET) {
if (value == EV_FREE) {
/*
* Leave the event reset and tell qemu_event_set that there
* are waiters. No need to retry, because there cannot be
* a concurent busy->free transition. After the CAS, the
* event will be either set or busy.
*/
if (atomic_cmpxchg(&ev->value, EV_FREE, EV_BUSY) == EV_SET) {
return;
}
}
futex_wait(ev, EV_BUSY);
}
}
void do_run_on_cpu(CPUState *cpu, run_on_cpu_func func, run_on_cpu_data data,
QemuMutex *mutex)
{
struct qemu_work_item wi;
if (qemu_cpu_is_self(cpu)) {
func(cpu, data);
return;
}
wi.func = func;
wi.data = data;
wi.done = false;
wi.free = false;
wi.exclusive = false;
queue_work_on_cpu(cpu, &wi);
while (!atomic_mb_read(&wi.done)) {
CPUState *self_cpu = current_cpu;
qemu_cond_wait(&qemu_work_cond, mutex);
current_cpu = self_cpu;
}
}
PostcopyState postcopy_state_get(void)
{
return atomic_mb_read(&incoming_postcopy_state);
}