[dpdk-dev] [RFC 2/2] vhost: support vhost-user request only handled by external backend

[Maxime Coquelin <maxime.coquelin@redhat.com>]

External backends may have specific requests to handle, and so
we don't want the vhost-user lib to handle these requests as
errors.

This patch also catch the case where a request is neither handled
by the external backend nor by the vhost library.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 lib/librte_vhost/vhost_user.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 36c0c676d..bae5ef1cc 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -1924,27 +1924,29 @@ vhost_user_msg_handler(int vid, int fd)
 	}
 
 	ret = read_vhost_message(fd, &msg);
-	if (ret <= 0 || msg.request.master >= VHOST_USER_MAX) {
+	if (ret <= 0) {
 		if (ret < 0)
 			RTE_LOG(ERR, VHOST_CONFIG,
 				"vhost read message failed\n");
-		else if (ret == 0)
+		else
 			RTE_LOG(INFO, VHOST_CONFIG,
 				"vhost peer closed\n");
-		else
-			RTE_LOG(ERR, VHOST_CONFIG,
-				"vhost read incorrect message\n");
 
 		return -1;
 	}
 
 	ret = 0;
-	if (msg.request.master != VHOST_USER_IOTLB_MSG)
-		RTE_LOG(INFO, VHOST_CONFIG, "read message %s\n",
-			vhost_message_str[msg.request.master]);
-	else
-		RTE_LOG(DEBUG, VHOST_CONFIG, "read message %s\n",
-			vhost_message_str[msg.request.master]);
+	request = msg.request.master;
+	if (request < VHOST_USER_MAX && vhost_message_str[req]) {
+		if (request != VHOST_USER_IOTLB_MSG)
+			RTE_LOG(INFO, VHOST_CONFIG, "read message %s\n",
+				vhost_message_str[request]);
+		else if (
+			RTE_LOG(DEBUG, VHOST_CONFIG, "read message %s\n",
+				vhost_message_str[request]);
+	} else {
+		RTE_LOG(INFO, VHOST_CONFIG, "External request %d\n", request);
+	}
 
 	ret = vhost_user_check_and_alloc_queue_pair(dev, &msg);
 	if (ret < 0) {
@@ -1960,7 +1962,7 @@ vhost_user_msg_handler(int vid, int fd)
 	 * inactive, so it is safe. Otherwise taking the access_lock
 	 * would cause a dead lock.
 	 */
-	switch (msg.request.master) {
+	switch (request) {
 	case VHOST_USER_SET_FEATURES:
 	case VHOST_USER_SET_PROTOCOL_FEATURES:
 	case VHOST_USER_SET_OWNER:
@@ -1985,6 +1987,7 @@ vhost_user_msg_handler(int vid, int fd)
 
 	}
 
+	ret = RTE_VHOST_MSG_RESULT_ERR;
 	if (dev->extern_ops.pre_msg_handle) {
 		ret = (*dev->extern_ops.pre_msg_handle)(dev->vid,
 				(void *)&msg, &skip_master);
@@ -1997,7 +2000,6 @@ vhost_user_msg_handler(int vid, int fd)
 			goto skip_to_post_handle;
 	}
 
-	request = msg.request.master;
 	if (request > VHOST_USER_NONE && request < VHOST_USER_MAX) {
 		if (!vhost_message_handlers[request])
 			goto skip_to_post_handle;
-- 
2.20.1