vhost: add thread-unsafe async registration

This patch adds thread unsafe version for async register and unregister functions. Signed-off-by: Jiayu Hu <[email protected]> Reviewed-by: Chenbo Xia <[email protected]> Reviewed-by: Maxime Coquelin <[email protected]>
minhuw · Jul 21, 2021 · fa51f1a · fa51f1a
1 parent acbc388
commit fa51f1a
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Showing 4 changed files with 173 additions and 36 deletions.
diff --git a/doc/guides/prog_guide/vhost_lib.rst b/doc/guides/prog_guide/vhost_lib.rst
@@ -256,6 +256,14 @@ The following is an overview of some key Vhost API functions:
     vhost invokes this function to get the copy data completed by async
     devices.
 
+* ``rte_vhost_async_channel_register_thread_unsafe(vid, queue_id, config, ops)``
+
+  Register an async copy device channel for a vhost queue without
+  performing any locking.
+
+  This function is only safe to call in vhost callback functions
+  (i.e., struct vhost_device_ops).
+
 * ``rte_vhost_async_channel_unregister(vid, queue_id)``
 
   Unregister the async copy device channel from a vhost queue.
@@ -268,6 +276,14 @@ The following is an overview of some key Vhost API functions:
   devices for all vhost queues in destroy_device(), when a
   virtio device is paused or shut down.
 
+* ``rte_vhost_async_channel_unregister_thread_unsafe(vid, queue_id)``
+
+  Unregister the async copy device channel for a vhost queue without
+  performing any locking.
+
+  This function is only safe to call in vhost callback functions
+  (i.e., struct vhost_device_ops).
+
 * ``rte_vhost_submit_enqueue_burst(vid, queue_id, pkts, count, comp_pkts, comp_count)``
 
   Submit an enqueue request to transmit ``count`` packets from host to guest

diff --git a/lib/vhost/rte_vhost_async.h b/lib/vhost/rte_vhost_async.h
@@ -140,6 +140,47 @@ int rte_vhost_async_channel_register(int vid, uint16_t queue_id,
 __rte_experimental
 int rte_vhost_async_channel_unregister(int vid, uint16_t queue_id);
 
+/**
+ * Register an async channel for a vhost queue without performing any
+ * locking
+ *
+ * @note This function does not perform any locking, and is only safe to
+ *       call in vhost callback functions.
+ *
+ * @param vid
+ *  vhost device id async channel to be attached to
+ * @param queue_id
+ *  vhost queue id async channel to be attached to
+ * @param config
+ *  Async channel configuration
+ * @param ops
+ *  Async channel operation callbacks
+ * @return
+ *  0 on success, -1 on failures
+ */
+__rte_experimental
+int rte_vhost_async_channel_register_thread_unsafe(int vid, uint16_t queue_id,
+	struct rte_vhost_async_config config,
+	struct rte_vhost_async_channel_ops *ops);
+
+/**
+ * Unregister an async channel for a vhost queue without performing any
+ * locking
+ *
+ * @note This function does not perform any locking, and is only safe to
+ *       call in vhost callback functions.
+ *
+ * @param vid
+ *  vhost device id async channel to be detached from
+ * @param queue_id
+ *  vhost queue id async channel to be detached from
+ * @return
+ *  0 on success, -1 on failures
+ */
+__rte_experimental
+int rte_vhost_async_channel_unregister_thread_unsafe(int vid,
+		uint16_t queue_id);
+
 /**
  * This function submits enqueue data to async engine. Successfully
  * enqueued packets can be transfer completed or being occupied by DMA

diff --git a/lib/vhost/version.map b/lib/vhost/version.map
@@ -82,4 +82,6 @@ EXPERIMENTAL {
 
 	# added in 21.08
 	rte_vhost_async_get_inflight;
+	rte_vhost_async_channel_register_thread_unsafe;
+	rte_vhost_async_channel_unregister_thread_unsafe;
 };
diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
@@ -1619,43 +1619,19 @@ int rte_vhost_extern_callback_register(int vid,
 	return 0;
 }
 
-int
-rte_vhost_async_channel_register(int vid, uint16_t queue_id,
+static __rte_always_inline int
+async_channel_register(int vid, uint16_t queue_id,
 		struct rte_vhost_async_config config,
 		struct rte_vhost_async_channel_ops *ops)
 {
-	struct vhost_virtqueue *vq;
 	struct virtio_net *dev = get_device(vid);
-
-	if (dev == NULL || ops == NULL)
-		return -1;
-
-	if (queue_id >= VHOST_MAX_VRING)
-		return -1;
-
-	vq = dev->virtqueue[queue_id];
-
-	if (unlikely(vq == NULL || !dev->async_copy))
-		return -1;
-
-	if (unlikely(!(config.features & RTE_VHOST_ASYNC_INORDER))) {
-		VHOST_LOG_CONFIG(ERR,
-			"async copy is not supported on non-inorder mode "
-			"(vid %d, qid: %d)\n", vid, queue_id);
-		return -1;
-	}
-
-	if (unlikely(ops->check_completed_copies == NULL ||
-		ops->transfer_data == NULL))
-		return -1;
-
-	rte_spinlock_lock(&vq->access_lock);
+	struct vhost_virtqueue *vq = dev->virtqueue[queue_id];
 
 	if (unlikely(vq->async_registered)) {
 		VHOST_LOG_CONFIG(ERR,
 			"async register failed: channel already registered "
 			"(vid %d, qid: %d)\n", vid, queue_id);
-		goto reg_out;
+		return -1;
 	}
 
 	vq->async_pkts_info = rte_malloc_socket(NULL,
@@ -1666,7 +1642,7 @@ rte_vhost_async_channel_register(int vid, uint16_t queue_id,
 		VHOST_LOG_CONFIG(ERR,
 			"async register failed: cannot allocate memory for async_pkts_info "
 			"(vid %d, qid: %d)\n", vid, queue_id);
-		goto reg_out;
+		return -1;
 	}
 
 	vq->it_pool = rte_malloc_socket(NULL,
@@ -1677,7 +1653,7 @@ rte_vhost_async_channel_register(int vid, uint16_t queue_id,
 		VHOST_LOG_CONFIG(ERR,
 			"async register failed: cannot allocate memory for it_pool "
 			"(vid %d, qid: %d)\n", vid, queue_id);
-		goto reg_out;
+		return -1;
 	}
 
 	vq->vec_pool = rte_malloc_socket(NULL,
@@ -1688,7 +1664,7 @@ rte_vhost_async_channel_register(int vid, uint16_t queue_id,
 		VHOST_LOG_CONFIG(ERR,
 			"async register failed: cannot allocate memory for vec_pool "
 			"(vid %d, qid: %d)\n", vid, queue_id);
-		goto reg_out;
+		return -1;
 	}
 
 	if (vq_is_packed(dev)) {
@@ -1700,7 +1676,7 @@ rte_vhost_async_channel_register(int vid, uint16_t queue_id,
 			VHOST_LOG_CONFIG(ERR,
 				"async register failed: cannot allocate memory for async buffers "
 				"(vid %d, qid: %d)\n", vid, queue_id);
-			goto reg_out;
+			return -1;
 		}
 	} else {
 		vq->async_descs_split = rte_malloc_socket(NULL,
@@ -1711,7 +1687,7 @@ rte_vhost_async_channel_register(int vid, uint16_t queue_id,
 			VHOST_LOG_CONFIG(ERR,
 				"async register failed: cannot allocate memory for async descs "
 				"(vid %d, qid: %d)\n", vid, queue_id);
-			goto reg_out;
+			return -1;
 		}
 	}
 
@@ -1721,10 +1697,78 @@ rte_vhost_async_channel_register(int vid, uint16_t queue_id,
 
 	vq->async_registered = true;
 
-reg_out:
+	return 0;
+}
+
+int
+rte_vhost_async_channel_register(int vid, uint16_t queue_id,
+		struct rte_vhost_async_config config,
+		struct rte_vhost_async_channel_ops *ops)
+{
+	struct vhost_virtqueue *vq;
+	struct virtio_net *dev = get_device(vid);
+	int ret;
+
+	if (dev == NULL || ops == NULL)
+		return -1;
+
+	if (queue_id >= VHOST_MAX_VRING)
+		return -1;
+
+	vq = dev->virtqueue[queue_id];
+
+	if (unlikely(vq == NULL || !dev->async_copy))
+		return -1;
+
+	if (unlikely(!(config.features & RTE_VHOST_ASYNC_INORDER))) {
+		VHOST_LOG_CONFIG(ERR,
+			"async copy is not supported on non-inorder mode "
+			"(vid %d, qid: %d)\n", vid, queue_id);
+		return -1;
+	}
+
+	if (unlikely(ops->check_completed_copies == NULL ||
+		ops->transfer_data == NULL))
+		return -1;
+
+	rte_spinlock_lock(&vq->access_lock);
+	ret = async_channel_register(vid, queue_id, config, ops);
 	rte_spinlock_unlock(&vq->access_lock);
 
-	return 0;
+	return ret;
+}
+
+int
+rte_vhost_async_channel_register_thread_unsafe(int vid, uint16_t queue_id,
+		struct rte_vhost_async_config config,
+		struct rte_vhost_async_channel_ops *ops)
+{
+	struct vhost_virtqueue *vq;
+	struct virtio_net *dev = get_device(vid);
+
+	if (dev == NULL || ops == NULL)
+		return -1;
+
+	if (queue_id >= VHOST_MAX_VRING)
+		return -1;
+
+	vq = dev->virtqueue[queue_id];
+
+	if (unlikely(vq == NULL || !dev->async_copy))
+		return -1;
+
+	if (unlikely(!(config.features & RTE_VHOST_ASYNC_INORDER))) {
+		VHOST_LOG_CONFIG(ERR,
+			"async copy is not supported on non-inorder mode "
+			"(vid %d, qid: %d)\n", vid, queue_id);
+		return -1;
+	}
+
+	if (unlikely(ops->check_completed_copies == NULL ||
+		ops->transfer_data == NULL))
+		return -1;
+
+	return async_channel_register(vid, queue_id, config, ops);
 }
 
 int
@@ -1775,6 +1819,41 @@ rte_vhost_async_channel_unregister(int vid, uint16_t queue_id)
 	return ret;
 }
 
+int
+rte_vhost_async_channel_unregister_thread_unsafe(int vid, uint16_t queue_id)
+{
+	struct vhost_virtqueue *vq;
+	struct virtio_net *dev = get_device(vid);
+
+	if (dev == NULL)
+		return -1;
+
+	if (queue_id >= VHOST_MAX_VRING)
+		return -1;
+
+	vq = dev->virtqueue[queue_id];
+
+	if (vq == NULL)
+		return -1;
+
+	if (!vq->async_registered)
+		return 0;
+
+	if (vq->async_pkts_inflight_n) {
+		VHOST_LOG_CONFIG(ERR, "Failed to unregister async channel. "
+			"async inflight packets must be completed before unregistration.\n");
+		return -1;
+	}
+
+	vhost_free_async_mem(vq);
+
+	vq->async_ops.transfer_data = NULL;
+	vq->async_ops.check_completed_copies = NULL;
+	vq->async_registered = false;
+
+	return 0;
+}
+
 int rte_vhost_async_get_inflight(int vid, uint16_t queue_id)
 {
 	struct vhost_virtqueue *vq;
@@ -1805,7 +1884,6 @@ int rte_vhost_async_get_inflight(int vid, uint16_t queue_id)
 	rte_spinlock_unlock(&vq->access_lock);
 
 	return ret;
-
 }
 
 RTE_LOG_REGISTER_SUFFIX(vhost_config_log_level, config, INFO);