RE: [PATCH v2] vhost: add runtime locking check in unsafe APIs

["Xia, Chenbo" <chenbo.xia@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Wednesday, May 11, 2022 2:59 PM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>; Ding, Xuan
> <xuan.ding@intel.com>; Hu, Jiayu <jiayu.hu@intel.com>; Jiang, Cheng1
> <cheng1.jiang@intel.com>; Pai G, Sunil <sunil.pai.g@intel.com>;
> david.marchand@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH v2] vhost: add runtime locking check in unsafe APIs
> 
> This patch adds runtime checks in unsafe Vhost async APIs,
> to ensure the access lock is taken.
> 
> The detection won't work every time, as another thread
> could take the lock, but it would help to detect misuse
> of these unsafe API.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  lib/vhost/vhost.c      | 18 ++++++++++++++++++
>  lib/vhost/virtio_net.c |  6 ++++++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
> index df0bb9d043..39cbeb415c 100644
> --- a/lib/vhost/vhost.c
> +++ b/lib/vhost/vhost.c
> @@ -1732,6 +1732,12 @@ rte_vhost_async_channel_register_thread_unsafe(int
> vid, uint16_t queue_id)
>  	if (unlikely(vq == NULL || !dev->async_copy))
>  		return -1;
> 
> +	if (unlikely(!rte_spinlock_is_locked(&vq->access_lock))) {
> +		VHOST_LOG_CONFIG(ERR, "(%s) %s() called without access lock
> taken.\n",
> +				dev->ifname, __func__);
> +		return -1;
> +	}
> +
>  	return async_channel_register(vid, queue_id);
>  }
> 
> @@ -1796,6 +1802,12 @@
> rte_vhost_async_channel_unregister_thread_unsafe(int vid, uint16_t
> queue_id)
>  	if (vq == NULL)
>  		return -1;
> 
> +	if (unlikely(!rte_spinlock_is_locked(&vq->access_lock))) {
> +		VHOST_LOG_CONFIG(ERR, "(%s) %s() called without access lock
> taken.\n",
> +				dev->ifname, __func__);
> +		return -1;
> +	}
> +
>  	if (!vq->async)
>  		return 0;
> 
> @@ -1925,6 +1937,12 @@ rte_vhost_async_get_inflight_thread_unsafe(int vid,
> uint16_t queue_id)
>  	if (vq == NULL)
>  		return ret;
> 
> +	if (unlikely(!rte_spinlock_is_locked(&vq->access_lock))) {
> +		VHOST_LOG_CONFIG(ERR, "(%s) %s() called without access lock
> taken.\n",
> +				dev->ifname, __func__);
> +		return -1;
> +	}
> +
>  	if (!vq->async)
>  		return ret;
> 
> diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
> index 5f432b0d77..59163bc165 100644
> --- a/lib/vhost/virtio_net.c
> +++ b/lib/vhost/virtio_net.c
> @@ -2091,6 +2091,12 @@ rte_vhost_clear_queue_thread_unsafe(int vid,
> uint16_t queue_id,
> 
>  	vq = dev->virtqueue[queue_id];
> 
> +	if (unlikely(!rte_spinlock_is_locked(&vq->access_lock))) {
> +		VHOST_LOG_DATA(ERR, "(%s) %s() called without access lock
> taken.\n",
> +				dev->ifname, __func__);
> +		return -1;
> +	}
> +
>  	if (unlikely(!vq->async)) {
>  		VHOST_LOG_DATA(ERR, "(%s) %s: async not registered for queue
> id %d.\n",
>  			dev->ifname, __func__, queue_id);
> --
> 2.35.1

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>