[Qemu-devel] pause_all_vcpus() TCG bug?

[Andreas Färber]

Hello,

This is today's function, with annotations and question inline:

void pause_all_vcpus(void)
{
    CPUArchState *penv = first_cpu;

    qemu_clock_enable(vm_clock, false);
    while (penv) {
        CPUState *pcpu = ENV_GET_CPU(penv);
        pcpu->stop = true;
        qemu_cpu_kick(pcpu);
        penv = penv->next_cpu;
    }

/* So, at this point penv == NULL. */

    if (qemu_in_vcpu_thread()) {
        cpu_stop_current();
        if (!kvm_enabled()) {
            while (penv) {

/* Looks like this can never be true then? */
/* Is penv = first_cpu; missing? */

                CPUState *pcpu = ENV_GET_CPU(penv);
                pcpu->stop = 0;

/* 0 instead of false may hint at a mismerge... */

                pcpu->stopped = true;
                penv = penv->next_cpu;
            }
            return;
        }
    }

    while (!all_vcpus_paused()) {
        qemu_cond_wait(&qemu_pause_cond, &qemu_global_mutex);
        penv = first_cpu;
        while (penv) {
            qemu_cpu_kick(ENV_GET_CPU(penv));
            penv = penv->next_cpu;
        }
    }
}

Thanks,
Andreas

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