[PATCH v7 1/8] lib/librte_vhost: add vhost user message handlers

[Fan Zhang <roy.fan.zhang@intel.com>]

Previously, vhost library lacks the support to the vhost backend
other than net such as adding private data or registering vhost-user
message handlers. This patch fills the gap by adding data pointer and
vhost-user pre and post message handlers to vhost library.

Signed-off-by: Fan Zhang <roy.fan.zhang@intel.com>
---
 lib/librte_vhost/vhost.c      |  2 +-
 lib/librte_vhost/vhost.h      | 53 +++++++++++++++++++++++++++++++++++++++++--
 lib/librte_vhost/vhost_user.c | 31 ++++++++++++++++++++++++-
 3 files changed, 82 insertions(+), 4 deletions(-)

diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
index 1f17cdd75..8ad9ea8c6 100644
--- a/lib/librte_vhost/vhost.c
+++ b/lib/librte_vhost/vhost.c
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: BSD-3-Clause
- * Copyright(c) 2010-2016 Intel Corporation
+ * Copyright(c) 2010-2017 Intel Corporation
  */
 
 #include <linux/vhost.h>
diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
index c14a90529..c9b64461d 100644
--- a/lib/librte_vhost/vhost.h
+++ b/lib/librte_vhost/vhost.h
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: BSD-3-Clause
- * Copyright(c) 2010-2014 Intel Corporation
+ * Copyright(c) 2010-2018 Intel Corporation
  */
 
 #ifndef _VHOST_NET_CDEV_H_
@@ -212,6 +212,51 @@ struct guest_page {
 };
 
 /**
+ * function prototype for the vhost backend to handler specific vhost user
+ * messages prior to the master message handling
+ *
+ * @param vid
+ *  vhost device id
+ * @param msg
+ *  Message pointer.
+ * @param require_reply
+ *  If the handler requires sending a reply, this varaible shall be written 1,
+ *  otherwise 0.
+ * @param skip_master
+ *  If the handler requires skipping the master message handling, this variable
+ *  shall be written 1, otherwise 0.
+ * @return
+ *  0 on success, -1 on failure
+ */
+typedef int (*vhost_msg_pre_handle)(int vid, void *msg,
+		uint32_t *require_reply, uint32_t *skip_master);
+
+/**
+ * function prototype for the vhost backend to handler specific vhost user
+ * messages after the master message handling is done
+ *
+ * @param vid
+ *  vhost device id
+ * @param msg
+ *  Message pointer.
+ * @param require_reply
+ *  If the handler requires sending a reply, this varaible shall be written 1,
+ *  otherwise 0.
+ * @return
+ *  0 on success, -1 on failure
+ */
+typedef int (*vhost_msg_post_handle)(int vid, void *msg,
+		uint32_t *require_reply);
+
+/**
+ * pre and post vhost user message handlers
+ */
+struct vhost_user_extern_ops {
+	vhost_msg_pre_handle pre_msg_handle;
+	vhost_msg_post_handle post_msg_handle;
+};
+
+/**
  * Device structure contains all configuration information relating
  * to the device.
  */
@@ -249,8 +294,12 @@ struct virtio_net {
 	 * It's set to -1 for the default software implementation.
 	 */
 	int			vdpa_dev_id;
-} __rte_cache_aligned;
 
+	/* private data for virtio device */
+	void			*extern_data;
+	/* pre and post vhost user message handlers for the device */
+	struct vhost_user_extern_ops extern_ops;
+} __rte_cache_aligned;
 
 #define VHOST_LOG_PAGE	4096
 
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 157cf2f60..ecc1a3eea 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: BSD-3-Clause
- * Copyright(c) 2010-2016 Intel Corporation
+ * Copyright(c) 2010-2018 Intel Corporation
  */
 
 /* Security model
@@ -1429,6 +1429,7 @@ vhost_user_msg_handler(int vid, int fd)
 	int did = -1;
 	int ret;
 	int unlock_required = 0;
+	uint32_t skip_master = 0;
 
 	dev = get_device(vid);
 	if (dev == NULL)
@@ -1506,6 +1507,21 @@ vhost_user_msg_handler(int vid, int fd)
 
 	}
 
+	if (dev->extern_ops.pre_msg_handle) {
+		uint32_t need_reply;
+
+		ret = (*dev->extern_ops.pre_msg_handle)(dev->vid,
+				(void *)&msg, &need_reply, &skip_master);
+		if (ret < 0)
+			goto skip_to_reply;
+
+		if (need_reply)
+			send_vhost_reply(fd, &msg);
+
+		if (skip_master)
+			goto skip_to_post_handle;
+	}
+
 	switch (msg.request.master) {
 	case VHOST_USER_GET_FEATURES:
 		msg.payload.u64 = vhost_user_get_features(dev);
@@ -1606,9 +1622,22 @@ vhost_user_msg_handler(int vid, int fd)
 	default:
 		ret = -1;
 		break;
+	}
+
+skip_to_post_handle:
+	if (dev->extern_ops.post_msg_handle) {
+		uint32_t need_reply;
+
+		ret = (*dev->extern_ops.post_msg_handle)(
+				dev->vid, (void *)&msg, &need_reply);
+		if (ret < 0)
+			goto skip_to_reply;
 
+		if (need_reply)
+			send_vhost_reply(fd, &msg);
 	}
 
+skip_to_reply:
 	if (unlock_required)
 		vhost_user_unlock_all_queue_pairs(dev);
 
-- 
2.13.6