Re: [PATCH v2] hw/nvme: Use ioeventfd to handle doorbell updates

[Keith Busch]

On Thu, Jun 30, 2022 at 11:22:31AM +0800, Jinhao Fan wrote:
> +static int nvme_init_sq_ioeventfd(NvmeSQueue *sq)
> +{
> +    NvmeCtrl *n = sq->ctrl;
> +    uint16_t offset = sq->sqid << 3;
> +    int ret;
> +
> +    ret = event_notifier_init(&sq->notifier, 0);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +
> +    event_notifier_set_handler(&sq->notifier, nvme_sq_notifier);
> +    memory_region_add_eventfd(&n->iomem,
> +                              0x1000 + offset, 4, false, 0, &sq->notifier);
> +
> +    return 0;
> +}
> +
>  static void nvme_free_sq(NvmeSQueue *sq, NvmeCtrl *n)
>  {
>      n->sq[sq->sqid] = NULL;
>      timer_free(sq->timer);
> +    event_notifier_cleanup(&sq->notifier);
>      g_free(sq->io_req);
>      if (sq->sqid) {
>          g_free(sq);

I believe there needs to be a corresponding memory_region_del_eventfd() when
deleting the queue before event_notifier_cleanup(), otherwise you'll leak
invalid listeners.