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Date: Wed, 01 May 2013 15:33:09 +0200
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Subject: [Qemu-devel] pause_all_vcpus() TCG bug?
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To: qemu-devel <qemu-devel@nongnu.org>
Cc: Peter Maydell <peter.maydell@linaro.org>, =?UTF-8?B?6Zmz6Z+L5Lu7?= <chenwj@iis.sinica.edu.tw>

Hello,

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

void pause_all_vcpus(void)
{
    CPUArchState *penv =3D first_cpu;

    qemu_clock_enable(vm_clock, false);
    while (penv) {
        CPUState *pcpu =3D ENV_GET_CPU(penv);
        pcpu->stop =3D true;
        qemu_cpu_kick(pcpu);
        penv =3D penv->next_cpu;
    }

/* So, at this point penv =3D=3D NULL. */

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

/* Looks like this can never be true then? */
/* Is penv =3D first_cpu; missing? */

                CPUState *pcpu =3D ENV_GET_CPU(penv);
                pcpu->stop =3D 0;

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

                pcpu->stopped =3D true;
                penv =3D penv->next_cpu;
            }
            return;
        }
    }

    while (!all_vcpus_paused()) {
        qemu_cond_wait(&qemu_pause_cond, &qemu_global_mutex);
        penv =3D first_cpu;
        while (penv) {
            qemu_cpu_kick(ENV_GET_CPU(penv));
            penv =3D penv->next_cpu;
        }
    }
}

Thanks,
Andreas

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