C++ VirtioBusClass::set_host_notifier方法代码示例

/* Context: QEMU global mutex held */
void virtio_scsi_dataplane_start(VirtIOSCSI *s)
{
    int i;
    int rc;
    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s)));
    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);

    if (s->dataplane_started ||
        s->dataplane_starting ||
        s->dataplane_fenced ||
        s->ctx != iothread_get_aio_context(vs->conf.iothread)) {
        return;
    }

    s->dataplane_starting = true;

    /* Set up guest notifier (irq) */
    rc = k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, true);
    if (rc != 0) {
        fprintf(stderr, "virtio-scsi: Failed to set guest notifiers (%d), "
                "ensure -enable-kvm is set\n", rc);
        goto fail_guest_notifiers;
    }

    aio_context_acquire(s->ctx);
    rc = virtio_scsi_vring_init(s, vs->ctrl_vq, 0);
    if (rc) {
        goto fail_vrings;
    }
    rc = virtio_scsi_vring_init(s, vs->event_vq, 1);
    if (rc) {
        goto fail_vrings;
    }
    for (i = 0; i < vs->conf.num_queues; i++) {
        rc = virtio_scsi_vring_init(s, vs->cmd_vqs[i], i + 2);
        if (rc) {
            goto fail_vrings;
        }
    }

    s->dataplane_starting = false;
    s->dataplane_started = true;
    aio_context_release(s->ctx);
    return;

fail_vrings:
    virtio_scsi_clear_aio(s);
    aio_context_release(s->ctx);
    for (i = 0; i < vs->conf.num_queues + 2; i++) {
        k->set_host_notifier(qbus->parent, i, false);
    }
    k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false);
fail_guest_notifiers:
    s->dataplane_fenced = true;
    s->dataplane_starting = false;
    s->dataplane_started = true;
}

/* Context: QEMU global mutex held */
void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s)
{
    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s->vdev)));
    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
    VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);
    int r;

    if (vblk->dataplane_started || s->starting) {
        return;
    }

    s->starting = true;
    s->vq = virtio_get_queue(s->vdev, 0);

    /* Set up guest notifier (irq) */
    r = k->set_guest_notifiers(qbus->parent, 1, true);
    if (r != 0) {
        fprintf(stderr, "virtio-blk failed to set guest notifier (%d), "
                "ensure -enable-kvm is set\n", r);
        goto fail_guest_notifiers;
    }
    s->guest_notifier = virtio_queue_get_guest_notifier(s->vq);

    /* Set up virtqueue notify */
    r = k->set_host_notifier(qbus->parent, 0, true);
    if (r != 0) {
        fprintf(stderr, "virtio-blk failed to set host notifier (%d)\n", r);
        goto fail_host_notifier;
    }

    s->starting = false;
    vblk->dataplane_started = true;
    trace_virtio_blk_data_plane_start(s);

    blk_set_aio_context(s->conf->conf.blk, s->ctx);

    /* Kick right away to begin processing requests already in vring */
    event_notifier_set(virtio_queue_get_host_notifier(s->vq));

    /* Get this show started by hooking up our callbacks */
    aio_context_acquire(s->ctx);
    virtio_queue_aio_set_host_notifier_handler(s->vq, s->ctx,
                                               virtio_blk_data_plane_handle_output);
    aio_context_release(s->ctx);
    return;

  fail_host_notifier:
    k->set_guest_notifiers(qbus->parent, 1, false);
  fail_guest_notifiers:
    vblk->dataplane_disabled = true;
    s->starting = false;
    vblk->dataplane_started = true;
}

static int virtio_scsi_vring_init(VirtIOSCSI *s, VirtQueue *vq, int n)
{
    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s)));
    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
    int rc;

    /* Set up virtqueue notify */
    rc = k->set_host_notifier(qbus->parent, n, true);
    if (rc != 0) {
        fprintf(stderr, "virtio-scsi: Failed to set host notifier (%d)\n",
                rc);
        s->dataplane_fenced = true;
        return rc;
    }

    virtio_queue_aio_set_host_notifier_handler(vq, s->ctx, true, true);
    return 0;
}

/* Context: QEMU global mutex held */
void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
{
    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s->vdev)));
    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
    VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);


    /* Better luck next time. */
    if (s->disabled) {
        s->disabled = false;
        return;
    }
    if (!s->started || s->stopping) {
        return;
    }
    s->stopping = true;
    vblk->complete_request = s->saved_complete_request;
    trace_virtio_blk_data_plane_stop(s);

    aio_context_acquire(s->ctx);

    /* Stop notifications for new requests from guest */
    aio_set_event_notifier(s->ctx, &s->host_notifier, true, NULL);

    /* Drain and switch bs back to the QEMU main loop */
    blk_set_aio_context(s->conf->conf.blk, qemu_get_aio_context());

    aio_context_release(s->ctx);

    /* Sync vring state back to virtqueue so that non-dataplane request
     * processing can continue when we disable the host notifier below.
     */
    vring_teardown(&s->vring, s->vdev, 0);

    k->set_host_notifier(qbus->parent, 0, false);

    /* Clean up guest notifier (irq) */
    k->set_guest_notifiers(qbus->parent, 1, false);

    s->started = false;
    s->stopping = false;
}

/* Context: QEMU global mutex held */
void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
{
    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s->vdev)));
    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
    VirtIOBlock *vblk = VIRTIO_BLK(s->vdev);

    if (!vblk->dataplane_started || s->stopping) {
        return;
    }

    /* Better luck next time. */
    if (s->disabled) {
        s->disabled = false;
        vblk->dataplane_started = false;
        return;
    }
    s->stopping = true;
    trace_virtio_blk_data_plane_stop(s);

    aio_context_acquire(s->ctx);

    /* Stop notifications for new requests from guest */
    virtio_queue_aio_set_host_notifier_handler(s->vq, s->ctx, false, false);

    /* Drain and switch bs back to the QEMU main loop */
    blk_set_aio_context(s->conf->conf.blk, qemu_get_aio_context());

    aio_context_release(s->ctx);

    k->set_host_notifier(qbus->parent, 0, false);

    /* Clean up guest notifier (irq) */
    k->set_guest_notifiers(qbus->parent, 1, false);

    vblk->dataplane_started = false;
    s->stopping = false;
}

/* Context: QEMU global mutex held */
void virtio_scsi_dataplane_stop(VirtIOSCSI *s)
{
    BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(s)));
    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
    int i;

    if (!s->dataplane_started || s->dataplane_stopping) {
        return;
    }

    /* Better luck next time. */
    if (s->dataplane_fenced) {
        s->dataplane_fenced = false;
        s->dataplane_started = false;
        return;
    }
    s->dataplane_stopping = true;
    assert(s->ctx == iothread_get_aio_context(vs->conf.iothread));

    aio_context_acquire(s->ctx);

    virtio_scsi_clear_aio(s);

    blk_drain_all(); /* ensure there are no in-flight requests */

    aio_context_release(s->ctx);

    for (i = 0; i < vs->conf.num_queues + 2; i++) {
        k->set_host_notifier(qbus->parent, i, false);
    }

    /* Clean up guest notifier (irq) */
    k->set_guest_notifiers(qbus->parent, vs->conf.num_queues + 2, false);
    s->dataplane_stopping = false;
    s->dataplane_started = false;
}