vhost: add APIs for datapath configuration

This patch adds APIs for datapath configuration.

The did of the vhost-user socket can be set to identify the backend device,
in this case each vhost-user socket can have only 1 connection. The did is
set to -1 by default when the software datapath is used.

Signed-off-by: Zhihong Wang <zhihong.wang@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

lib/librte_vhost/rte_vhost.h

@@ -199,6 +199,41 @@ int rte_vhost_driver_register(const char *path, uint64_t flags);
 /* Unregister vhost driver. This is only meaningful to vhost user. */
 int rte_vhost_driver_unregister(const char *path);
 
+/**
+ * Set the vdpa device id, enforce single connection per socket
+ *
+ * @param path
+ *  The vhost-user socket file path
+ * @param did
+ *  Device id
+ * @return
+ *  0 on success, -1 on failure
+ */
+int __rte_experimental
+rte_vhost_driver_attach_vdpa_device(const char *path, int did);
+
+/**
+ * Unset the vdpa device id
+ *
+ * @param path
+ *  The vhost-user socket file path
+ * @return
+ *  0 on success, -1 on failure
+ */
+int __rte_experimental
+rte_vhost_driver_detach_vdpa_device(const char *path);
+
+/**
+ * Get the device id
+ *
+ * @param path
+ *  The vhost-user socket file path
+ * @return
+ *  Device id, -1 on failure
+ */
+int __rte_experimental
+rte_vhost_driver_get_vdpa_device_id(const char *path);
+
 /**
  * Set the feature bits the vhost-user driver supports.
  *
@@ -464,6 +499,17 @@ int rte_vhost_vring_call(int vid, uint16_t vring_idx);
  */
 uint32_t rte_vhost_rx_queue_count(int vid, uint16_t qid);
 
+/**
+ * Get vdpa device id for vhost device.
+ *
+ * @param vid
+ *  vhost device id
+ * @return
+ *  device id
+ */
+int __rte_experimental
+rte_vhost_get_vdpa_device_id(int vid);
+
 #ifdef __cplusplus
 }
 #endif

lib/librte_vhost/rte_vhost_version.map

@@ -65,4 +65,8 @@ EXPERIMENTAL {
 	rte_vdpa_unregister_device;
 	rte_vdpa_find_device_id;
 	rte_vdpa_get_device;
+	rte_vhost_driver_attach_vdpa_device;
+	rte_vhost_driver_detach_vdpa_device;
+	rte_vhost_driver_get_vdpa_device_id;
+	rte_vhost_get_vdpa_device_id;
 } DPDK_18.02;

lib/librte_vhost/socket.c

@@ -51,6 +51,13 @@ struct vhost_user_socket {
 	uint64_t supported_features;
 	uint64_t features;
 
+	/*
+	 * Device id to identify a specific backend device.
+	 * It's set to -1 for the default software implementation.
+	 * If valid, one socket can have 1 connection only.
+	 */
+	int vdpa_dev_id;
+
 	struct vhost_device_ops const *notify_ops;
 };
 
@@ -545,6 +552,52 @@ find_vhost_user_socket(const char *path)
 	return NULL;
 }
 
+int
+rte_vhost_driver_attach_vdpa_device(const char *path, int did)
+{
+	struct vhost_user_socket *vsocket;
+
+	if (rte_vdpa_get_device(did) == NULL)
+		return -1;
+
+	pthread_mutex_lock(&vhost_user.mutex);
+	vsocket = find_vhost_user_socket(path);
+	if (vsocket)
+		vsocket->vdpa_dev_id = did;
+	pthread_mutex_unlock(&vhost_user.mutex);
+
+	return vsocket ? 0 : -1;
+}
+
+int
+rte_vhost_driver_detach_vdpa_device(const char *path)
+{
+	struct vhost_user_socket *vsocket;
+
+	pthread_mutex_lock(&vhost_user.mutex);
+	vsocket = find_vhost_user_socket(path);
+	if (vsocket)
+		vsocket->vdpa_dev_id = -1;
+	pthread_mutex_unlock(&vhost_user.mutex);
+
+	return vsocket ? 0 : -1;
+}
+
+int
+rte_vhost_driver_get_vdpa_device_id(const char *path)
+{
+	struct vhost_user_socket *vsocket;
+	int did = -1;
+
+	pthread_mutex_lock(&vhost_user.mutex);
+	vsocket = find_vhost_user_socket(path);
+	if (vsocket)
+		did = vsocket->vdpa_dev_id;
+	pthread_mutex_unlock(&vhost_user.mutex);
+
+	return did;
+}
+
 int
 rte_vhost_driver_disable_features(const char *path, uint64_t features)
 {

lib/librte_vhost/vhost.c

@@ -283,6 +283,7 @@ vhost_new_device(void)
 	dev->vid = i;
 	dev->flags = VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 	dev->slave_req_fd = -1;
+	dev->vdpa_dev_id = -1;
 
 	return i;
 }
@@ -310,6 +311,31 @@ vhost_destroy_device(int vid)
 	vhost_devices[vid] = NULL;
 }
 
+void
+vhost_attach_vdpa_device(int vid, int did)
+{
+	struct virtio_net *dev = get_device(vid);
+
+	if (dev == NULL)
+		return;
+
+	if (rte_vdpa_get_device(did) == NULL)
+		return;
+
+	dev->vdpa_dev_id = did;
+}
+
+void
+vhost_detach_vdpa_device(int vid)
+{
+	struct virtio_net *dev = get_device(vid);
+
+	if (dev == NULL)
+		return;
+
+	dev->vdpa_dev_id = -1;
+}
+
 void
 vhost_set_ifname(int vid, const char *if_name, unsigned int if_len)
 {
@@ -614,3 +640,13 @@ rte_vhost_rx_queue_count(int vid, uint16_t qid)
 
 	return *((volatile uint16_t *)&vq->avail->idx) - vq->last_avail_idx;
 }
+
+int rte_vhost_get_vdpa_device_id(int vid)
+{
+	struct virtio_net *dev = get_device(vid);
+
+	if (dev == NULL)
+		return -1;
+
+	return dev->vdpa_dev_id;
+}

lib/librte_vhost/vhost.h

@@ -20,6 +20,7 @@
 #include <rte_rwlock.h>
 
 #include "rte_vhost.h"
+#include "rte_vdpa.h"
 
 /* Used to indicate that the device is running on a data core */
 #define VIRTIO_DEV_RUNNING 1
@@ -240,6 +241,12 @@ struct virtio_net {
 	struct guest_page       *guest_pages;
 
 	int			slave_req_fd;
+
+	/*
+	 * Device id to identify a specific backend device.
+	 * It's set to -1 for the default software implementation.
+	 */
+	int			vdpa_dev_id;
 } __rte_cache_aligned;
 
 
@@ -362,6 +369,9 @@ void free_vq(struct vhost_virtqueue *vq);
 
 int alloc_vring_queue(struct virtio_net *dev, uint32_t vring_idx);
 
+void vhost_attach_vdpa_device(int vid, int did);
+void vhost_detach_vdpa_device(int vid);
+
 void vhost_set_ifname(int, const char *if_name, unsigned int if_len);
 void vhost_enable_dequeue_zero_copy(int vid);
 void vhost_set_builtin_virtio_net(int vid, bool enable);