On 19/01/2018 09:44, Pavel Dovgalyuk wrote:
> while (all_cpu_threads_idle()) {
> + qemu_mutex_lock_iothread();
> stop_tcg_kick_timer();
> qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex);
> + qemu_mutex_unlock_iothread();
> }
cpu_has_work cannot be called outside BQL yet. You first need to access
cpu->interrupt_request with atomics.
In general, testing the condition outside the mutex is a very dangerous
pattern (and I'm usually the one who enjoys dangerous patterns).
But also, taking a slightly wider look:
> static void qemu_tcg_rr_wait_io_event(CPUState *cpu)
> {
> while (all_cpu_threads_idle()) {
> + qemu_mutex_lock_iothread();
> stop_tcg_kick_timer();
> qemu_cond_wait(cpu->halt_cond, &qemu_global_mutex);
> + qemu_mutex_unlock_iothread();
> }
>
> start_tcg_kick_timer();
>
> qemu_wait_io_event_common(cpu);
> -
> - qemu_mutex_unlock_iothread();
> }
>
You are adding a qemu_mutex_lock_iothread to a function that wasn't
there before. Either it was broken before, or it is now.
Paolo
