[dpdk-dev,RFC,1/2] vhost: make capabilities configurable

diff --git a/lib/librte_vhost/rte_vhost.h b/lib/librte_vhost/rte_vhost.h
index f653644..17b4c6d 100644
--- a/lib/librte_vhost/rte_vhost.h
+++ b/lib/librte_vhost/rte_vhost.h
@@ -209,6 +209,56 @@  int rte_vhost_driver_unregister(const char *path);
 int rte_vhost_driver_set_features(const char *path, uint64_t features);
 
 /**
+ * Get the protocol feature bits before feature negotiation.
+ *
+ * @param path
+ *  The vhost-user socket file path
+ * @param protocol_features
+ *  A pointer to store the queried protocol feature bits
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vhost_driver_get_protocol_features(const char *path,
+		uint64_t *protocol_features);
+
+/**
+ * Set the protocol feature bits the vhost-user driver supports.
+ *
+ * @param path
+ *  The vhost-user socket file path
+ * @param protocol_features
+ *  Supported protocol features
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vhost_driver_set_protocol_features(const char *path,
+		uint64_t protocol_features);
+
+/**
+ * Get the queue number before feature negotiation.
+ *
+ * @param path
+ *  The vhost-user socket file path
+ * @param queue_num
+ *  A pointer to store the queried queue number
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vhost_driver_get_queue_num(const char *path, uint16_t *queue_num);
+
+/**
+ * Set the queue number the vhost-user driver supports.
+ *
+ * @param path
+ *  The vhost-user socket file path
+ * @param queue_num
+ *  Supported queue number
+ * @return
+ *  0 on success, -1 on failure
+ */
+int rte_vhost_driver_set_queue_num(const char *path, uint16_t queue_num);
+
+/**
  * Enable vhost-user driver features.
  *
  * Note that
diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
index 422da00..742f772 100644
--- a/lib/librte_vhost/socket.c
+++ b/lib/librte_vhost/socket.c
@@ -78,7 +78,10 @@  struct vhost_user_socket {
 	 * features negotiation.
 	 */
 	uint64_t supported_features;
+	uint64_t supported_protocol_features;
 	uint64_t features;
+	uint64_t protocol_features;
+	uint16_t queue_num;
 
 	struct vhost_device_ops const *notify_ops;
 };
@@ -613,6 +616,75 @@  rte_vhost_driver_get_features(const char *path, uint64_t *features)
 	}
 }
 
+int rte_vhost_driver_set_protocol_features(const char *path,
+		uint64_t protocol_features)
+{
+	struct vhost_user_socket *vsocket;
+
+	pthread_mutex_lock(&vhost_user.mutex);
+	vsocket = find_vhost_user_socket(path);
+	if (vsocket) {
+		vsocket->supported_protocol_features = protocol_features;
+		vsocket->protocol_features = protocol_features;
+	}
+	pthread_mutex_unlock(&vhost_user.mutex);
+
+	return vsocket ? 0 : -1;
+}
+
+int
+rte_vhost_driver_get_protocol_features(const char *path,
+		uint64_t *protocol_features)
+{
+	struct vhost_user_socket *vsocket;
+
+	pthread_mutex_lock(&vhost_user.mutex);
+	vsocket = find_vhost_user_socket(path);
+	if (vsocket)
+		*protocol_features = vsocket->protocol_features;
+	pthread_mutex_unlock(&vhost_user.mutex);
+
+	if (!vsocket) {
+		RTE_LOG(ERR, VHOST_CONFIG,
+			"socket file %s is not registered yet.\n", path);
+		return -1;
+	} else {
+		return 0;
+	}
+}
+
+int rte_vhost_driver_set_queue_num(const char *path, uint16_t queue_num)
+{
+	struct vhost_user_socket *vsocket;
+
+	pthread_mutex_lock(&vhost_user.mutex);
+	vsocket = find_vhost_user_socket(path);
+	if (vsocket)
+		vsocket->queue_num = queue_num;
+	pthread_mutex_unlock(&vhost_user.mutex);
+
+	return vsocket ? 0 : -1;
+}
+
+int rte_vhost_driver_get_queue_num(const char *path, uint16_t *queue_num)
+{
+	struct vhost_user_socket *vsocket;
+
+	pthread_mutex_lock(&vhost_user.mutex);
+	vsocket = find_vhost_user_socket(path);
+	if (vsocket)
+		*queue_num = vsocket->queue_num;
+	pthread_mutex_unlock(&vhost_user.mutex);
+
+	if (!vsocket) {
+		RTE_LOG(ERR, VHOST_CONFIG,
+			"socket file %s is not registered yet.\n", path);
+		return -1;
+	} else {
+		return 0;
+	}
+}
+
 /*
  * Register a new vhost-user socket; here we could act as server
  * (the default case), or client (when RTE_VHOST_USER_CLIENT) flag
@@ -675,6 +747,11 @@  rte_vhost_driver_register(const char *path, uint64_t flags)
 		vsocket->features &= ~(1ULL << VIRTIO_F_IOMMU_PLATFORM);
 	}
 
+	vsocket->supported_protocol_features = VHOST_USER_PROTOCOL_FEATURES;
+	vsocket->protocol_features           = VHOST_USER_PROTOCOL_FEATURES;
+
+	vsocket->queue_num = VHOST_MAX_QUEUE_PAIRS;
+
 	if ((flags & RTE_VHOST_USER_CLIENT) != 0) {
 		vsocket->reconnect = !(flags & RTE_VHOST_USER_NO_RECONNECT);
 		if (vsocket->reconnect && reconn_tid == 0) {
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index f4c7ce4..0a4d128 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -156,6 +156,18 @@  vhost_user_reset_owner(struct virtio_net *dev)
 }
 
 /*
+ * The max queue num.
+ */
+static uint16_t
+vhost_user_get_queue_num(struct virtio_net *dev)
+{
+	uint16_t queue_num = 0;
+
+	rte_vhost_driver_get_queue_num(dev->ifname, &queue_num);
+	return queue_num;
+}
+
+/*
  * The features that we support are requested.
  */
 static uint64_t
@@ -860,13 +872,17 @@  vhost_user_set_vring_enable(struct virtio_net *dev,
 	return 0;
 }
 
-static void
-vhost_user_get_protocol_features(struct virtio_net *dev,
-				 struct VhostUserMsg *msg)
+/*
+ * The protocol features that we support are requested.
+ */
+
+static uint64_t
+vhost_user_get_protocol_features(struct virtio_net *dev)
 {
-	uint64_t features, protocol_features = VHOST_USER_PROTOCOL_FEATURES;
+	uint64_t features, protocol_features;
 
 	rte_vhost_driver_get_features(dev->ifname, &features);
+	rte_vhost_driver_get_protocol_features(dev->ifname, &protocol_features);
 
 	/*
 	 * REPLY_ACK protocol feature is only mandatory for now
@@ -877,18 +893,27 @@  vhost_user_get_protocol_features(struct virtio_net *dev,
 	if (!(features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)))
 		protocol_features &= ~(1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK);
 
-	msg->payload.u64 = protocol_features;
-	msg->size = sizeof(msg->payload.u64);
+	return protocol_features;
 }
 
-static void
+static int
 vhost_user_set_protocol_features(struct virtio_net *dev,
 				 uint64_t protocol_features)
 {
-	if (protocol_features & ~VHOST_USER_PROTOCOL_FEATURES)
-		return;
+	uint64_t vhost_protocol_features = 0;
+
+	rte_vhost_driver_get_protocol_features(dev->ifname,
+			&vhost_protocol_features);
+	if (protocol_features & ~vhost_protocol_features) {
+		RTE_LOG(ERR, VHOST_CONFIG,
+			"(%d) received invalid negotiated protocol_features.\n",
+			dev->vid);
+		return -1;
+	}
 
 	dev->protocol_features = protocol_features;
+
+	return 0;
 }
 
 static int
@@ -1252,7 +1277,8 @@  vhost_user_msg_handler(int vid, int fd)
 		break;
 
 	case VHOST_USER_GET_PROTOCOL_FEATURES:
-		vhost_user_get_protocol_features(dev, &msg);
+		msg.payload.u64 = vhost_user_get_protocol_features(dev);
+		msg.size = sizeof(msg.payload.u64);
 		send_vhost_reply(fd, &msg);
 		break;
 	case VHOST_USER_SET_PROTOCOL_FEATURES:
@@ -1312,7 +1338,7 @@  vhost_user_msg_handler(int vid, int fd)
 		break;
 
 	case VHOST_USER_GET_QUEUE_NUM:
-		msg.payload.u64 = VHOST_MAX_QUEUE_PAIRS;
+		msg.payload.u64 = vhost_user_get_queue_num(dev);
 		msg.size = sizeof(msg.payload.u64);
 		send_vhost_reply(fd, &msg);
 		break;