C++ qemu_mutex_lock函数代码示例

void process_queued_cpu_work(CPUState *cpu)
{
    struct qemu_work_item *wi;

    if (cpu->queued_work_first == NULL) {
        return;
    }

    qemu_mutex_lock(&cpu->work_mutex);
    while (cpu->queued_work_first != NULL) {
        wi = cpu->queued_work_first;
        cpu->queued_work_first = wi->next;
        if (!cpu->queued_work_first) {
            cpu->queued_work_last = NULL;
        }
        qemu_mutex_unlock(&cpu->work_mutex);
        if (wi->exclusive) {
            /* Running work items outside the BQL avoids the following deadlock:
             * 1) start_exclusive() is called with the BQL taken while another
             * CPU is running; 2) cpu_exec in the other CPU tries to takes the
             * BQL, so it goes to sleep; start_exclusive() is sleeping too, so
             * neither CPU can proceed.
             */
            qemu_mutex_unlock_iothread();
            start_exclusive();
            wi->func(cpu, wi->data);
            end_exclusive();
            qemu_mutex_lock_iothread();
        } else {
            wi->func(cpu, wi->data);
        }
        qemu_mutex_lock(&cpu->work_mutex);
        if (wi->free) {
            g_free(wi);
        } else {
            atomic_mb_set(&wi->done, true);
        }
    }
    qemu_mutex_unlock(&cpu->work_mutex);
    qemu_cond_broadcast(&qemu_work_cond);
}

static inline void res_tbl_dealloc(RdmaRmResTbl *tbl, uint32_t handle)
{
    pr_dbg("%s, handle=%d\n", tbl->name, handle);

    qemu_mutex_lock(&tbl->lock);

    if (handle < tbl->tbl_sz) {
        clear_bit(handle, tbl->bitmap);
    }

    qemu_mutex_unlock(&tbl->lock);
}

static void char_pty_finalize(Object *obj)
{
    Chardev *chr = CHARDEV(obj);
    PtyChardev *s = PTY_CHARDEV(obj);

    qemu_mutex_lock(&chr->chr_write_lock);
    pty_chr_state(chr, 0);
    object_unref(OBJECT(s->ioc));
    pty_chr_timer_cancel(s);
    qemu_mutex_unlock(&chr->chr_write_lock);
    qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
}

static
void sifive_plic_set_claimed(SiFivePLICState *plic, int irq, bool claimed)
{
    qemu_mutex_lock(&plic->lock);
    uint32_t word = irq >> 5;
    if (claimed) {
        plic->claimed[word] |= (1 << (irq & 31));
    } else {
        plic->claimed[word] &= ~(1 << (irq & 31));
    }
    qemu_mutex_unlock(&plic->lock);
}

static
void sifive_plic_set_pending(SiFivePLICState *plic, int irq, bool pending)
{
    qemu_mutex_lock(&plic->lock);
    uint32_t word = irq >> 5;
    if (pending) {
        plic->pending[word] |= (1 << (irq & 31));
    } else {
        plic->pending[word] &= ~(1 << (irq & 31));
    }
    qemu_mutex_unlock(&plic->lock);
}

static void qemu_wait_io_event(CPUState *env)
{
    while (!tcg_has_work())
        qemu_cond_timedwait(env->halt_cond, &qemu_global_mutex, 1000);

    qemu_mutex_unlock(&qemu_global_mutex);

    /*
     * Users of qemu_global_mutex can be starved, having no chance
     * to acquire it since this path will get to it first.
     * So use another lock to provide fairness.
     */
    qemu_mutex_lock(&qemu_fair_mutex);
    qemu_mutex_unlock(&qemu_fair_mutex);

    qemu_mutex_lock(&qemu_global_mutex);
    if (env->stop) {
        env->stop = 0;
        env->stopped = 1;
        qemu_cond_signal(&qemu_pause_cond);
    }
}

void cpu_list_add(CPUState *cpu)
{
    qemu_mutex_lock(&qemu_cpu_list_lock);
    if (cpu->cpu_index == UNASSIGNED_CPU_INDEX) {
        cpu->cpu_index = cpu_get_free_index();
        assert(cpu->cpu_index != UNASSIGNED_CPU_INDEX);
    } else {
        assert(!cpu_index_auto_assigned);
    }
    QTAILQ_INSERT_TAIL(&cpus, cpu, node);
    qemu_mutex_unlock(&qemu_cpu_list_lock);

    finish_safe_work(cpu);
}

/**
 * Install new regions list
 */
static void hostmem_listener_commit(MemoryListener *listener)
{
    HostMem *hostmem = container_of(listener, HostMem, listener);

    qemu_mutex_lock(&hostmem->current_regions_lock);
    g_free(hostmem->current_regions);
    hostmem->current_regions = hostmem->new_regions;
    hostmem->num_current_regions = hostmem->num_new_regions;
    qemu_mutex_unlock(&hostmem->current_regions_lock);

    /* Reset new regions list */
    hostmem->new_regions = NULL;
    hostmem->num_new_regions = 0;
}

static void qemu_tcg_wait_io_event(void)
{
    CPUState *env;

    while (!any_cpu_has_work())
        qemu_cond_timedwait(tcg_halt_cond, &qemu_global_mutex, 1000);

    qemu_mutex_unlock(&qemu_global_mutex);

    /*
     * Users of qemu_global_mutex can be starved, having no chance
     * to acquire it since this path will get to it first.
     * So use another lock to provide fairness.
     */
    qemu_mutex_lock(&qemu_fair_mutex);
    qemu_mutex_unlock(&qemu_fair_mutex);

    qemu_mutex_lock(&qemu_global_mutex);

    for (env = first_cpu; env != NULL; env = env->next_cpu) {
        qemu_wait_io_event_common(env);
    }
}

static void iothread_complete(UserCreatable *obj, Error **errp)
{
    Error *local_error = NULL;
    IOThread *iothread = IOTHREAD(obj);
    char *name, *thread_name;

    iothread->stopping = false;
    iothread->running = true;
    iothread->thread_id = -1;
    iothread->ctx = aio_context_new(&local_error);
    if (!iothread->ctx) {
        error_propagate(errp, local_error);
        return;
    }

    aio_context_set_poll_params(iothread->ctx,
                                iothread->poll_max_ns,
                                iothread->poll_grow,
                                iothread->poll_shrink,
                                &local_error);
    if (local_error) {
        error_propagate(errp, local_error);
        aio_context_unref(iothread->ctx);
        iothread->ctx = NULL;
        return;
    }

    qemu_mutex_init(&iothread->init_done_lock);
    qemu_cond_init(&iothread->init_done_cond);
    iothread->once = (GOnce) G_ONCE_INIT;

    /* This assumes we are called from a thread with useful CPU affinity for us
     * to inherit.
     */
    name = object_get_canonical_path_component(OBJECT(obj));
    thread_name = g_strdup_printf("IO %s", name);
    qemu_thread_create(&iothread->thread, thread_name, iothread_run,
                       iothread, QEMU_THREAD_JOINABLE);
    g_free(thread_name);
    g_free(name);

    /* Wait for initialization to complete */
    qemu_mutex_lock(&iothread->init_done_lock);
    while (iothread->thread_id == -1) {
        qemu_cond_wait(&iothread->init_done_cond,
                       &iothread->init_done_lock);
    }
    qemu_mutex_unlock(&iothread->init_done_lock);
}

static void queue_work_on_cpu(CPUState *cpu, struct qemu_work_item *wi)
{
    qemu_mutex_lock(&cpu->work_mutex);
    if (cpu->queued_work_first == NULL) {
        cpu->queued_work_first = wi;
    } else {
        cpu->queued_work_last->next = wi;
    }
    cpu->queued_work_last = wi;
    wi->next = NULL;
    wi->done = false;
    qemu_mutex_unlock(&cpu->work_mutex);

    qemu_cpu_kick(cpu);
}

void qemu_mutex_lock_iothread(void)
{
    LOGD_CPUS("%s1\n", __func__);
    if (!tcg_enabled()) {
    LOGD_CPUS("%s2\n", __func__);    
        qemu_mutex_lock(&qemu_global_mutex);
        LOGD_CPUS("%s3\n", __func__);
    } else {
        LOGD_CPUS("%s4\n", __func__);
        iothread_requesting_mutex = true;
        if (qemu_mutex_trylock(&qemu_global_mutex)) {
            LOGD_CPUS("%s5\n", __func__);
            qemu_cpu_kick_thread(first_cpu);
            LOGD_CPUS("%s6\n", __func__);
            qemu_mutex_lock(&qemu_global_mutex);
            LOGD_CPUS("%s7\n", __func__);
        }
        LOGD_CPUS("%s8\n", __func__);
        iothread_requesting_mutex = false;
        LOGD_CPUS("%s9\n", __func__);
        qemu_cond_broadcast(&qemu_io_proceeded_cond);
        LOGD_CPUS("%s10\n", __func__);
    }
}

QEMUBH *aio_bh_new(AioContext *ctx, QEMUBHFunc *cb, void *opaque)
{
    QEMUBH *bh;
    bh = g_new0(QEMUBH, 1);
    bh->ctx = ctx;
    bh->cb = cb;
    bh->opaque = opaque;
    qemu_mutex_lock(&ctx->bh_lock);
    bh->next = ctx->first_bh;
    /* Make sure that the members are ready before putting bh into list */
    smp_wmb();
    ctx->first_bh = bh;
    qemu_mutex_unlock(&ctx->bh_lock);
    return bh;
}

static void pci_edu_uninit(PCIDevice *pdev)
{
    EduState *edu = DO_UPCAST(EduState, pdev, pdev);

    qemu_mutex_lock(&edu->thr_mutex);
    edu->stopping = true;
    qemu_mutex_unlock(&edu->thr_mutex);
    qemu_cond_signal(&edu->thr_cond);
    qemu_thread_join(&edu->thread);

    qemu_cond_destroy(&edu->thr_cond);
    qemu_mutex_destroy(&edu->thr_mutex);

    timer_del(&edu->dma_timer);
}

void cpu_list_remove(CPUState *cpu)
{
    qemu_mutex_lock(&qemu_cpu_list_lock);
    if (!QTAILQ_IN_USE(cpu, node)) {
        /* there is nothing to undo since cpu_exec_init() hasn't been called */
        qemu_mutex_unlock(&qemu_cpu_list_lock);
        return;
    }

    assert(!(cpu_index_auto_assigned && cpu != QTAILQ_LAST(&cpus, CPUTailQ)));

    QTAILQ_REMOVE(&cpus, cpu, node);
    cpu->cpu_index = UNASSIGNED_CPU_INDEX;
    qemu_mutex_unlock(&qemu_cpu_list_lock);
}