xref: /spdk/lib/vhost/vhost_internal.h (revision a4009e7ad3d0aa0cfda4ce321e22161cbd1a26dc)
1 /*   SPDX-License-Identifier: BSD-3-Clause
2  *   Copyright (C) 2017 Intel Corporation.
3  *   All rights reserved.
4  */
5 
6 #ifndef SPDK_VHOST_INTERNAL_H
7 #define SPDK_VHOST_INTERNAL_H
8 #include <linux/virtio_config.h>
9 
10 #include "spdk/stdinc.h"
11 
12 #include <rte_vhost.h>
13 
14 #include "spdk_internal/vhost_user.h"
15 #include "spdk/bdev.h"
16 #include "spdk/log.h"
17 #include "spdk/util.h"
18 #include "spdk/rpc.h"
19 #include "spdk/config.h"
20 
21 #define SPDK_VHOST_MAX_VQUEUES	256
22 #define SPDK_VHOST_MAX_VQ_SIZE	1024
23 
24 #define SPDK_VHOST_SCSI_CTRLR_MAX_DEVS 8
25 
26 #define SPDK_VHOST_IOVS_MAX 129
27 
28 #define SPDK_VHOST_VQ_MAX_SUBMISSIONS	32
29 
30 /*
31  * Rate at which stats are checked for interrupt coalescing.
32  */
33 #define SPDK_VHOST_STATS_CHECK_INTERVAL_MS 10
34 /*
35  * Default threshold at which interrupts start to be coalesced.
36  */
37 #define SPDK_VHOST_VQ_IOPS_COALESCING_THRESHOLD 60000
38 
39 /*
40  * Currently coalescing is not used by default.
41  * Setting this to value > 0 here or by RPC will enable coalescing.
42  */
43 #define SPDK_VHOST_COALESCING_DELAY_BASE_US 0
44 
45 #define SPDK_VHOST_FEATURES ((1ULL << VHOST_F_LOG_ALL) | \
46 	(1ULL << VHOST_USER_F_PROTOCOL_FEATURES) | \
47 	(1ULL << VIRTIO_F_VERSION_1) | \
48 	(1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | \
49 	(1ULL << VIRTIO_RING_F_EVENT_IDX) | \
50 	(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
51 	(1ULL << VIRTIO_F_ANY_LAYOUT))
52 
53 #define SPDK_VHOST_DISABLED_FEATURES ((1ULL << VIRTIO_RING_F_EVENT_IDX) | \
54 	(1ULL << VIRTIO_F_NOTIFY_ON_EMPTY))
55 
56 #define VRING_DESC_F_AVAIL	(1ULL << VRING_PACKED_DESC_F_AVAIL)
57 #define VRING_DESC_F_USED	(1ULL << VRING_PACKED_DESC_F_USED)
58 #define VRING_DESC_F_AVAIL_USED	(VRING_DESC_F_AVAIL | VRING_DESC_F_USED)
59 
60 typedef struct rte_vhost_resubmit_desc spdk_vhost_resubmit_desc;
61 typedef struct rte_vhost_resubmit_info spdk_vhost_resubmit_info;
62 typedef struct rte_vhost_inflight_desc_packed	spdk_vhost_inflight_desc;
63 
64 struct spdk_vhost_virtqueue {
65 	struct rte_vhost_vring vring;
66 	struct rte_vhost_ring_inflight vring_inflight;
67 	uint16_t last_avail_idx;
68 	uint16_t last_used_idx;
69 
70 	struct {
71 		/* To mark a descriptor as available in packed ring
72 		 * Equal to avail_wrap_counter in spec.
73 		 */
74 		uint8_t avail_phase	: 1;
75 		/* To mark a descriptor as used in packed ring
76 		 * Equal to used_wrap_counter in spec.
77 		 */
78 		uint8_t used_phase	: 1;
79 		uint8_t padding		: 5;
80 		bool packed_ring	: 1;
81 	} packed;
82 
83 	void *tasks;
84 
85 	/* Request count from last stats check */
86 	uint32_t req_cnt;
87 
88 	/* Request count from last event */
89 	uint16_t used_req_cnt;
90 
91 	/* How long interrupt is delayed */
92 	uint32_t irq_delay_time;
93 
94 	/* Next time when we need to send event */
95 	uint64_t next_event_time;
96 
97 	/* Associated vhost_virtqueue in the virtio device's virtqueue list */
98 	uint32_t vring_idx;
99 
100 	struct spdk_vhost_session *vsession;
101 
102 	struct spdk_interrupt *intr;
103 } __attribute((aligned(SPDK_CACHE_LINE_SIZE)));
104 
105 struct spdk_vhost_session {
106 	struct spdk_vhost_dev *vdev;
107 
108 	/* rte_vhost connection ID. */
109 	int vid;
110 
111 	/* Unique session ID. */
112 	uint64_t id;
113 	/* Unique session name. */
114 	char *name;
115 
116 	bool started;
117 	bool starting;
118 	bool interrupt_mode;
119 
120 	struct rte_vhost_memory *mem;
121 
122 	int task_cnt;
123 
124 	uint16_t max_queues;
125 
126 	uint64_t negotiated_features;
127 
128 	/* Local copy of device coalescing settings. */
129 	uint32_t coalescing_delay_time_base;
130 	uint32_t coalescing_io_rate_threshold;
131 
132 	/* Next time when stats for event coalescing will be checked. */
133 	uint64_t next_stats_check_time;
134 
135 	/* Interval used for event coalescing checking. */
136 	uint64_t stats_check_interval;
137 
138 	/* Session's stop poller will only try limited times to destroy the session. */
139 	uint32_t stop_retry_count;
140 
141 	struct spdk_vhost_virtqueue virtqueue[SPDK_VHOST_MAX_VQUEUES];
142 
143 	TAILQ_ENTRY(spdk_vhost_session) tailq;
144 };
145 
146 struct spdk_vhost_user_dev {
147 	struct spdk_vhost_dev *vdev;
148 
149 	const struct spdk_vhost_user_dev_backend *user_backend;
150 
151 	/* Saved original values used to setup coalescing to avoid integer
152 	 * rounding issues during save/load config.
153 	 */
154 	uint32_t coalescing_delay_us;
155 	uint32_t coalescing_iops_threshold;
156 
157 	bool registered;
158 
159 	/* Use this lock to protect multiple sessions. */
160 	pthread_mutex_t lock;
161 
162 	/* Current connections to the device */
163 	TAILQ_HEAD(, spdk_vhost_session) vsessions;
164 
165 	/* Increment-only session counter */
166 	uint64_t vsessions_num;
167 
168 	/* Number of pending asynchronous operations */
169 	uint32_t pending_async_op_num;
170 };
171 
172 struct spdk_vhost_dev {
173 	char *name;
174 	char *path;
175 
176 	struct spdk_thread *thread;
177 
178 	uint64_t virtio_features;
179 	uint64_t disabled_features;
180 	uint64_t protocol_features;
181 
182 	const struct spdk_vhost_dev_backend *backend;
183 
184 	/* Context passed from transport */
185 	void *ctxt;
186 
187 	TAILQ_ENTRY(spdk_vhost_dev) tailq;
188 };
189 
190 static inline struct spdk_vhost_user_dev *
191 to_user_dev(struct spdk_vhost_dev *vdev)
192 {
193 	assert(vdev != NULL);
194 	return vdev->ctxt;
195 }
196 
197 /**
198  * \param vdev vhost device.
199  * \param vsession vhost session.
200  * \param arg user-provided parameter.
201  *
202  * \return negative values will break the foreach call, meaning
203  * the function won't be called again. Return codes zero and
204  * positive don't have any effect.
205  */
206 typedef int (*spdk_vhost_session_fn)(struct spdk_vhost_dev *vdev,
207 				     struct spdk_vhost_session *vsession,
208 				     void *arg);
209 
210 /**
211  * \param vdev vhost device.
212  * \param arg user-provided parameter.
213  */
214 typedef void (*spdk_vhost_dev_fn)(struct spdk_vhost_dev *vdev, void *arg);
215 
216 struct spdk_vhost_user_dev_backend {
217 	/**
218 	 * Size of additional per-session context data
219 	 * allocated whenever a new client connects.
220 	 */
221 	size_t session_ctx_size;
222 
223 	spdk_vhost_session_fn start_session;
224 	spdk_vhost_session_fn stop_session;
225 	int (*alloc_vq_tasks)(struct spdk_vhost_session *vsession, uint16_t qid);
226 	void (*register_vq_interrupt)(struct spdk_vhost_session *vsession, struct spdk_vhost_virtqueue *vq);
227 };
228 
229 enum vhost_backend_type {
230 	VHOST_BACKEND_BLK = 0,
231 	VHOST_BACKEND_SCSI,
232 };
233 
234 struct spdk_vhost_dev_backend {
235 	enum vhost_backend_type type;
236 
237 	int (*vhost_get_config)(struct spdk_vhost_dev *vdev, uint8_t *config, uint32_t len);
238 	int (*vhost_set_config)(struct spdk_vhost_dev *vdev, uint8_t *config,
239 				uint32_t offset, uint32_t size, uint32_t flags);
240 
241 	void (*dump_info_json)(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
242 	void (*write_config_json)(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
243 	int (*remove_device)(struct spdk_vhost_dev *vdev);
244 	int (*set_coalescing)(struct spdk_vhost_dev *vdev, uint32_t delay_base_us,
245 			      uint32_t iops_threshold);
246 	void (*get_coalescing)(struct spdk_vhost_dev *vdev, uint32_t *delay_base_us,
247 			       uint32_t *iops_threshold);
248 };
249 
250 void *vhost_gpa_to_vva(struct spdk_vhost_session *vsession, uint64_t addr, uint64_t len);
251 
252 uint16_t vhost_vq_avail_ring_get(struct spdk_vhost_virtqueue *vq, uint16_t *reqs,
253 				 uint16_t reqs_len);
254 
255 /**
256  * Get a virtio split descriptor at given index in given virtqueue.
257  * The descriptor will provide access to the entire descriptor
258  * chain. The subsequent descriptors are accessible via
259  * \c spdk_vhost_vring_desc_get_next.
260  * \param vsession vhost session
261  * \param vq virtqueue
262  * \param req_idx descriptor index
263  * \param desc pointer to be set to the descriptor
264  * \param desc_table descriptor table to be used with
265  * \c spdk_vhost_vring_desc_get_next. This might be either
266  * default virtqueue descriptor table or per-chain indirect
267  * table.
268  * \param desc_table_size size of the *desc_table*
269  * \return 0 on success, -1 if given index is invalid.
270  * If -1 is returned, the content of params is undefined.
271  */
272 int vhost_vq_get_desc(struct spdk_vhost_session *vsession, struct spdk_vhost_virtqueue *vq,
273 		      uint16_t req_idx, struct vring_desc **desc, struct vring_desc **desc_table,
274 		      uint32_t *desc_table_size);
275 
276 /**
277  * Get a virtio packed descriptor at given index in given virtqueue.
278  * The descriptor will provide access to the entire descriptor
279  * chain. The subsequent descriptors are accessible via
280  * \c vhost_vring_packed_desc_get_next.
281  * \param vsession vhost session
282  * \param vq virtqueue
283  * \param req_idx descriptor index
284  * \param desc pointer to be set to the descriptor
285  * \param desc_table descriptor table to be used with
286  * \c spdk_vhost_vring_desc_get_next. This might be either
287  * \c NULL or per-chain indirect table.
288  * \param desc_table_size size of the *desc_table*
289  * \return 0 on success, -1 if given index is invalid.
290  * If -1 is returned, the content of params is undefined.
291  */
292 int vhost_vq_get_desc_packed(struct spdk_vhost_session *vsession,
293 			     struct spdk_vhost_virtqueue *virtqueue,
294 			     uint16_t req_idx, struct vring_packed_desc **desc,
295 			     struct vring_packed_desc **desc_table, uint32_t *desc_table_size);
296 
297 int vhost_inflight_queue_get_desc(struct spdk_vhost_session *vsession,
298 				  spdk_vhost_inflight_desc *desc_array,
299 				  uint16_t req_idx, spdk_vhost_inflight_desc **desc,
300 				  struct vring_packed_desc  **desc_table, uint32_t *desc_table_size);
301 
302 /**
303  * Send IRQ/call client (if pending) for \c vq.
304  * \param vsession vhost session
305  * \param vq virtqueue
306  * \return
307  *   0 - if no interrupt was signalled
308  *   1 - if interrupt was signalled
309  */
310 int vhost_vq_used_signal(struct spdk_vhost_session *vsession, struct spdk_vhost_virtqueue *vq);
311 
312 /**
313  * Send IRQs for the queue that need to be signaled.
314  * \param vq virtqueue
315  */
316 void vhost_session_vq_used_signal(struct spdk_vhost_virtqueue *virtqueue);
317 
318 void vhost_vq_used_ring_enqueue(struct spdk_vhost_session *vsession,
319 				struct spdk_vhost_virtqueue *vq,
320 				uint16_t id, uint32_t len);
321 
322 /**
323  * Enqueue the entry to the used ring when device complete the request.
324  * \param vsession vhost session
325  * \param vq virtqueue
326  * \req_idx descriptor index. It's the first index of this descriptor chain.
327  * \num_descs descriptor count. It's the count of the number of buffers in the chain.
328  * \buffer_id descriptor buffer ID.
329  * \length device write length. Specify the length of the buffer that has been initialized
330  * (written to) by the device
331  * \inflight_head the head idx of this IO inflight desc chain.
332  */
333 void vhost_vq_packed_ring_enqueue(struct spdk_vhost_session *vsession,
334 				  struct spdk_vhost_virtqueue *virtqueue,
335 				  uint16_t num_descs, uint16_t buffer_id,
336 				  uint32_t length, uint16_t inflight_head);
337 
338 /**
339  * Get subsequent descriptor from given table.
340  * \param desc current descriptor, will be set to the
341  * next descriptor (NULL in case this is the last
342  * descriptor in the chain or the next desc is invalid)
343  * \param desc_table descriptor table
344  * \param desc_table_size size of the *desc_table*
345  * \return 0 on success, -1 if given index is invalid
346  * The *desc* param will be set regardless of the
347  * return value.
348  */
349 int vhost_vring_desc_get_next(struct vring_desc **desc,
350 			      struct vring_desc *desc_table, uint32_t desc_table_size);
351 static inline bool
352 vhost_vring_desc_is_wr(struct vring_desc *cur_desc)
353 {
354 	return !!(cur_desc->flags & VRING_DESC_F_WRITE);
355 }
356 
357 int vhost_vring_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
358 			    uint16_t *iov_index, const struct vring_desc *desc);
359 
360 bool vhost_vq_packed_ring_is_avail(struct spdk_vhost_virtqueue *virtqueue);
361 
362 /**
363  * Get subsequent descriptor from vq or desc table.
364  * \param desc current descriptor, will be set to the
365  * next descriptor (NULL in case this is the last
366  * descriptor in the chain or the next desc is invalid)
367  * \req_idx index of current desc, will be set to the next
368  * index. If desc_table != NULL the req_idx is the the vring index
369  * or the req_idx is the desc_table index.
370  * \param desc_table descriptor table
371  * \param desc_table_size size of the *desc_table*
372  * \return 0 on success, -1 if given index is invalid
373  * The *desc* param will be set regardless of the
374  * return value.
375  */
376 int vhost_vring_packed_desc_get_next(struct vring_packed_desc **desc, uint16_t *req_idx,
377 				     struct spdk_vhost_virtqueue *vq,
378 				     struct vring_packed_desc *desc_table,
379 				     uint32_t desc_table_size);
380 
381 bool vhost_vring_packed_desc_is_wr(struct vring_packed_desc *cur_desc);
382 
383 int vhost_vring_packed_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
384 				   uint16_t *iov_index, const struct vring_packed_desc *desc);
385 
386 bool vhost_vring_inflight_desc_is_wr(spdk_vhost_inflight_desc *cur_desc);
387 
388 int vhost_vring_inflight_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
389 				     uint16_t *iov_index, const spdk_vhost_inflight_desc *desc);
390 
391 uint16_t vhost_vring_packed_desc_get_buffer_id(struct spdk_vhost_virtqueue *vq, uint16_t req_idx,
392 		uint16_t *num_descs);
393 
394 static inline bool
395 __attribute__((always_inline))
396 vhost_dev_has_feature(struct spdk_vhost_session *vsession, unsigned feature_id)
397 {
398 	return vsession->negotiated_features & (1ULL << feature_id);
399 }
400 
401 int vhost_dev_register(struct spdk_vhost_dev *vdev, const char *name, const char *mask_str,
402 		       const struct spdk_json_val *params,
403 		       const struct spdk_vhost_dev_backend *backend,
404 		       const struct spdk_vhost_user_dev_backend *user_backend);
405 int vhost_dev_unregister(struct spdk_vhost_dev *vdev);
406 
407 void vhost_dump_info_json(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
408 
409 /*
410  * Set vhost session to run in interrupt or poll mode
411  */
412 void vhost_user_session_set_interrupt_mode(struct spdk_vhost_session *vsession,
413 		bool interrupt_mode);
414 
415 /*
416  * Memory registration functions used in start/stop device callbacks
417  */
418 void vhost_session_mem_register(struct rte_vhost_memory *mem);
419 void vhost_session_mem_unregister(struct rte_vhost_memory *mem);
420 
421 /*
422  * Call a function for each session of the provided vhost device.
423  * The function will be called one-by-one on each session's thread.
424  *
425  * \param vdev vhost device
426  * \param fn function to call on each session's thread
427  * \param cpl_fn function to be called at the end of the iteration on
428  * the vhost management thread.
429  * Optional, can be NULL.
430  * \param arg additional argument to the both callbacks
431  */
432 void vhost_user_dev_foreach_session(struct spdk_vhost_dev *dev,
433 				    spdk_vhost_session_fn fn,
434 				    spdk_vhost_dev_fn cpl_fn,
435 				    void *arg);
436 
437 /**
438  * Finish a blocking vhost_user_wait_for_session_stop() call and finally
439  * stop the session. This must be called on the session's lcore which
440  * used to receive all session-related messages (e.g. from
441  * vhost_user_dev_foreach_session()). After this call, the session-
442  * related messages will be once again processed by any arbitrary thread.
443  *
444  * Must be called under the vhost user device's session access lock.
445  *
446  * \param vsession vhost session
447  * \param response return code
448  */
449 void vhost_user_session_stop_done(struct spdk_vhost_session *vsession, int response);
450 
451 struct spdk_vhost_session *vhost_session_find_by_vid(int vid);
452 void vhost_session_install_rte_compat_hooks(struct spdk_vhost_session *vsession);
453 int vhost_register_unix_socket(const char *path, const char *ctrl_name,
454 			       uint64_t virtio_features, uint64_t disabled_features, uint64_t protocol_features);
455 int vhost_driver_unregister(const char *path);
456 int vhost_get_mem_table(int vid, struct rte_vhost_memory **mem);
457 int vhost_get_negotiated_features(int vid, uint64_t *negotiated_features);
458 
459 int remove_vhost_controller(struct spdk_vhost_dev *vdev);
460 
461 struct spdk_io_channel *vhost_blk_get_io_channel(struct spdk_vhost_dev *vdev);
462 void vhost_blk_put_io_channel(struct spdk_io_channel *ch);
463 
464 /* The spdk_bdev pointer should only be used to retrieve
465  * the device properties, ex. number of blocks or I/O type supported. */
466 struct spdk_bdev *vhost_blk_get_bdev(struct spdk_vhost_dev *vdev);
467 
468 /* Function calls from vhost.c to rte_vhost_user.c,
469  * shall removed once virtio transport abstraction is complete. */
470 int vhost_user_session_set_coalescing(struct spdk_vhost_dev *dev,
471 				      struct spdk_vhost_session *vsession, void *ctx);
472 int vhost_user_dev_set_coalescing(struct spdk_vhost_user_dev *user_dev, uint32_t delay_base_us,
473 				  uint32_t iops_threshold);
474 int vhost_user_dev_register(struct spdk_vhost_dev *vdev, const char *name,
475 			    struct spdk_cpuset *cpumask, const struct spdk_vhost_user_dev_backend *user_backend);
476 int vhost_user_dev_unregister(struct spdk_vhost_dev *vdev);
477 int vhost_user_init(void);
478 void vhost_user_fini(spdk_vhost_fini_cb vhost_cb);
479 int vhost_user_set_coalescing(struct spdk_vhost_dev *vdev, uint32_t delay_base_us,
480 			      uint32_t iops_threshold);
481 void vhost_user_get_coalescing(struct spdk_vhost_dev *vdev, uint32_t *delay_base_us,
482 			       uint32_t *iops_threshold);
483 
484 int virtio_blk_construct_ctrlr(struct spdk_vhost_dev *vdev, const char *address,
485 			       struct spdk_cpuset *cpumask, const struct spdk_json_val *params,
486 			       const struct spdk_vhost_user_dev_backend *user_backend);
487 int virtio_blk_destroy_ctrlr(struct spdk_vhost_dev *vdev);
488 
489 struct spdk_vhost_blk_task;
490 
491 typedef void (*virtio_blk_request_cb)(uint8_t status, struct spdk_vhost_blk_task *task,
492 				      void *cb_arg);
493 
494 struct spdk_vhost_blk_task {
495 	struct spdk_bdev_io *bdev_io;
496 	virtio_blk_request_cb cb;
497 	void *cb_arg;
498 
499 	volatile uint8_t *status;
500 
501 	/* for io wait */
502 	struct spdk_bdev_io_wait_entry bdev_io_wait;
503 	struct spdk_io_channel *bdev_io_wait_ch;
504 	struct spdk_vhost_dev *bdev_io_wait_vdev;
505 
506 	/** Number of bytes that were written. */
507 	uint32_t used_len;
508 	uint16_t iovcnt;
509 	struct iovec iovs[SPDK_VHOST_IOVS_MAX];
510 
511 	/** Size of whole payload in bytes */
512 	uint32_t payload_size;
513 };
514 
515 int virtio_blk_process_request(struct spdk_vhost_dev *vdev, struct spdk_io_channel *ch,
516 			       struct spdk_vhost_blk_task *task, virtio_blk_request_cb cb, void *cb_arg);
517 
518 typedef void (*bdev_event_cb_complete)(struct spdk_vhost_dev *vdev, void *ctx);
519 
520 #define SPDK_VIRTIO_BLK_TRSTRING_MAX_LEN 32
521 
522 struct spdk_virtio_blk_transport_ops {
523 	/**
524 	 * Transport name
525 	 */
526 	char name[SPDK_VIRTIO_BLK_TRSTRING_MAX_LEN];
527 
528 	/**
529 	 * Create a transport for the given transport opts
530 	 */
531 	struct spdk_virtio_blk_transport *(*create)(const struct spdk_json_val *params);
532 
533 	/**
534 	 * Dump transport-specific opts into JSON
535 	 */
536 	void (*dump_opts)(struct spdk_virtio_blk_transport *transport, struct spdk_json_write_ctx *w);
537 
538 	/**
539 	 * Destroy the transport
540 	 */
541 	int (*destroy)(struct spdk_virtio_blk_transport *transport,
542 		       spdk_vhost_fini_cb cb_fn);
543 
544 	/**
545 	 * Create vhost block controller
546 	 */
547 	int (*create_ctrlr)(struct spdk_vhost_dev *vdev, struct spdk_cpuset *cpumask,
548 			    const char *address, const struct spdk_json_val *params,
549 			    void *custom_opts);
550 
551 	/**
552 	 * Destroy vhost block controller
553 	 */
554 	int (*destroy_ctrlr)(struct spdk_vhost_dev *vdev);
555 
556 	/*
557 	 * Signal removal of the bdev.
558 	 */
559 	void (*bdev_event)(enum spdk_bdev_event_type type, struct spdk_vhost_dev *vdev,
560 			   bdev_event_cb_complete cb, void *cb_arg);
561 
562 	/**
563 	 * Set coalescing parameters.
564 	 */
565 	int (*set_coalescing)(struct spdk_vhost_dev *vdev, uint32_t delay_base_us,
566 			      uint32_t iops_threshold);
567 
568 	/**
569 	 * Get coalescing parameters.
570 	 */
571 	void (*get_coalescing)(struct spdk_vhost_dev *vdev, uint32_t *delay_base_us,
572 			       uint32_t *iops_threshold);
573 };
574 
575 struct spdk_virtio_blk_transport {
576 	const struct spdk_virtio_blk_transport_ops	*ops;
577 	TAILQ_ENTRY(spdk_virtio_blk_transport)		tailq;
578 };
579 
580 struct virtio_blk_transport_ops_list_element {
581 	struct spdk_virtio_blk_transport_ops			ops;
582 	TAILQ_ENTRY(virtio_blk_transport_ops_list_element)	link;
583 };
584 
585 void virtio_blk_transport_register(const struct spdk_virtio_blk_transport_ops *ops);
586 int virtio_blk_transport_create(const char *transport_name, const struct spdk_json_val *params);
587 int virtio_blk_transport_destroy(struct spdk_virtio_blk_transport *transport,
588 				 spdk_vhost_fini_cb cb_fn);
589 struct spdk_virtio_blk_transport *virtio_blk_transport_get_first(void);
590 struct spdk_virtio_blk_transport *virtio_blk_transport_get_next(
591 	struct spdk_virtio_blk_transport *transport);
592 void virtio_blk_transport_dump_opts(struct spdk_virtio_blk_transport *transport,
593 				    struct spdk_json_write_ctx *w);
594 struct spdk_virtio_blk_transport *virtio_blk_tgt_get_transport(const char *transport_name);
595 const struct spdk_virtio_blk_transport_ops *virtio_blk_get_transport_ops(
596 	const char *transport_name);
597 
598 void vhost_session_info_json(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
599 
600 /*
601  * Macro used to register new transports.
602  */
603 #define SPDK_VIRTIO_BLK_TRANSPORT_REGISTER(name, transport_ops) \
604 static void __attribute__((constructor)) _virtio_blk_transport_register_##name(void) \
605 { \
606 	virtio_blk_transport_register(transport_ops); \
607 }
608 
609 #endif /* SPDK_VHOST_INTERNAL_H */
610