xref: /spdk/lib/vhost/vhost_internal.h (revision 16d862d0380886f6fc765f68a87e240bb4295595)
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  * Timeout in seconds for vhost-user session stop message.
41  */
42 #define SPDK_VHOST_SESSION_STOP_TIMEOUT_IN_SEC 3
43 /*
44  * Stop retry timeout in seconds, this value should be greater than SPDK_VHOST_SESSION_STOP_TIMEOUT_IN_SEC.
45  */
46 #define SPDK_VHOST_SESSION_STOP_RETRY_TIMEOUT_IN_SEC (SPDK_VHOST_SESSION_STOP_TIMEOUT_IN_SEC + 1)
47 /*
48  * Stop retry period in microseconds
49  */
50 #define SPDK_VHOST_SESSION_STOP_RETRY_PERIOD_IN_US 1000
51 
52 /*
53  * Currently coalescing is not used by default.
54  * Setting this to value > 0 here or by RPC will enable coalescing.
55  */
56 #define SPDK_VHOST_COALESCING_DELAY_BASE_US 0
57 
58 #define SPDK_VHOST_FEATURES ((1ULL << VHOST_F_LOG_ALL) | \
59 	(1ULL << VHOST_USER_F_PROTOCOL_FEATURES) | \
60 	(1ULL << VIRTIO_F_VERSION_1) | \
61 	(1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | \
62 	(1ULL << VIRTIO_RING_F_EVENT_IDX) | \
63 	(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
64 	(1ULL << VIRTIO_F_ANY_LAYOUT))
65 
66 #define SPDK_VHOST_DISABLED_FEATURES ((1ULL << VIRTIO_RING_F_EVENT_IDX) | \
67 	(1ULL << VIRTIO_F_NOTIFY_ON_EMPTY))
68 
69 #define VRING_DESC_F_AVAIL	(1ULL << VRING_PACKED_DESC_F_AVAIL)
70 #define VRING_DESC_F_USED	(1ULL << VRING_PACKED_DESC_F_USED)
71 #define VRING_DESC_F_AVAIL_USED	(VRING_DESC_F_AVAIL | VRING_DESC_F_USED)
72 
73 typedef struct rte_vhost_resubmit_desc spdk_vhost_resubmit_desc;
74 typedef struct rte_vhost_resubmit_info spdk_vhost_resubmit_info;
75 typedef struct rte_vhost_inflight_desc_packed	spdk_vhost_inflight_desc;
76 
77 struct spdk_vhost_virtqueue {
78 	struct rte_vhost_vring vring;
79 	struct rte_vhost_ring_inflight vring_inflight;
80 	uint16_t last_avail_idx;
81 	uint16_t last_used_idx;
82 
83 	struct {
84 		/* To mark a descriptor as available in packed ring
85 		 * Equal to avail_wrap_counter in spec.
86 		 */
87 		uint8_t avail_phase	: 1;
88 		/* To mark a descriptor as used in packed ring
89 		 * Equal to used_wrap_counter in spec.
90 		 */
91 		uint8_t used_phase	: 1;
92 		uint8_t padding		: 5;
93 		bool packed_ring	: 1;
94 	} packed;
95 
96 	void *tasks;
97 
98 	/* Request count from last stats check */
99 	uint32_t req_cnt;
100 
101 	/* Request count from last event */
102 	uint16_t used_req_cnt;
103 
104 	/* How long interrupt is delayed */
105 	uint32_t irq_delay_time;
106 
107 	/* Next time when we need to send event */
108 	uint64_t next_event_time;
109 
110 	/* Associated vhost_virtqueue in the virtio device's virtqueue list */
111 	uint32_t vring_idx;
112 
113 	struct spdk_vhost_session *vsession;
114 	/* Polling group private thread context */
115 	void *poll_group;
116 
117 	struct spdk_interrupt *intr;
118 } __attribute((aligned(SPDK_CACHE_LINE_SIZE)));
119 
120 struct spdk_vhost_session {
121 	struct spdk_vhost_dev *vdev;
122 
123 	/* rte_vhost connection ID. */
124 	int vid;
125 
126 	/* Unique session ID. */
127 	uint64_t id;
128 	/* Unique session name. */
129 	char *name;
130 
131 	bool started;
132 	bool starting;
133 	bool needs_restart;
134 
135 	struct rte_vhost_memory *mem;
136 
137 	int task_cnt;
138 
139 	uint16_t max_queues;
140 	/* Maximum number of queues before restart, used with 'needs_restart' flag */
141 	uint16_t original_max_queues;
142 
143 	uint64_t negotiated_features;
144 
145 	/* Local copy of device coalescing settings. */
146 	uint32_t coalescing_delay_time_base;
147 	uint32_t coalescing_io_rate_threshold;
148 
149 	/* Next time when stats for event coalescing will be checked. */
150 	uint64_t next_stats_check_time;
151 
152 	/* Interval used for event coalescing checking. */
153 	uint64_t stats_check_interval;
154 
155 	/* Session's stop poller will only try limited times to destroy the session. */
156 	uint32_t stop_retry_count;
157 
158 	/**
159 	 * DPDK calls our callbacks synchronously but the work those callbacks
160 	 * perform needs to be async. Luckily, all DPDK callbacks are called on
161 	 * a DPDK-internal pthread and only related to the current session, so we'll
162 	 * just wait on a semaphore of this session in there.
163 	 */
164 	sem_t dpdk_sem;
165 
166 	/** Return code for the current DPDK callback */
167 	int dpdk_response;
168 
169 	struct spdk_vhost_virtqueue virtqueue[SPDK_VHOST_MAX_VQUEUES];
170 
171 	TAILQ_ENTRY(spdk_vhost_session) tailq;
172 };
173 
174 struct spdk_vhost_user_dev {
175 	struct spdk_vhost_dev *vdev;
176 
177 	const struct spdk_vhost_user_dev_backend *user_backend;
178 
179 	/* Saved original values used to setup coalescing to avoid integer
180 	 * rounding issues during save/load config.
181 	 */
182 	uint32_t coalescing_delay_us;
183 	uint32_t coalescing_iops_threshold;
184 
185 	bool registered;
186 
187 	/* Use this lock to protect multiple sessions. */
188 	pthread_mutex_t lock;
189 
190 	/* Current connections to the device */
191 	TAILQ_HEAD(, spdk_vhost_session) vsessions;
192 
193 	/* Increment-only session counter */
194 	uint64_t vsessions_num;
195 
196 	/* Number of pending asynchronous operations */
197 	uint32_t pending_async_op_num;
198 };
199 
200 struct spdk_vhost_dev {
201 	char *name;
202 	char *path;
203 
204 	bool use_default_cpumask;
205 	struct spdk_thread *thread;
206 
207 	uint64_t virtio_features;
208 	uint64_t disabled_features;
209 	uint64_t protocol_features;
210 
211 	const struct spdk_vhost_dev_backend *backend;
212 
213 	/* Context passed from transport */
214 	void *ctxt;
215 
216 	TAILQ_ENTRY(spdk_vhost_dev) tailq;
217 };
218 
219 static inline struct spdk_vhost_user_dev *
220 to_user_dev(struct spdk_vhost_dev *vdev)
221 {
222 	assert(vdev != NULL);
223 	return vdev->ctxt;
224 }
225 
226 /**
227  * \param vdev vhost device.
228  * \param vsession vhost session.
229  * \param arg user-provided parameter.
230  *
231  * \return negative values will break the foreach call, meaning
232  * the function won't be called again. Return codes zero and
233  * positive don't have any effect.
234  */
235 typedef int (*spdk_vhost_session_fn)(struct spdk_vhost_dev *vdev,
236 				     struct spdk_vhost_session *vsession,
237 				     void *arg);
238 
239 /**
240  * \param vdev vhost device.
241  * \param arg user-provided parameter.
242  */
243 typedef void (*spdk_vhost_dev_fn)(struct spdk_vhost_dev *vdev, void *arg);
244 
245 struct spdk_vhost_user_dev_backend {
246 	/**
247 	 * Size of additional per-session context data
248 	 * allocated whenever a new client connects.
249 	 */
250 	size_t session_ctx_size;
251 
252 	spdk_vhost_session_fn start_session;
253 	spdk_vhost_session_fn stop_session;
254 	int (*alloc_vq_tasks)(struct spdk_vhost_session *vsession, uint16_t qid);
255 	int (*enable_vq)(struct spdk_vhost_session *vsession, struct spdk_vhost_virtqueue *vq);
256 };
257 
258 enum vhost_backend_type {
259 	VHOST_BACKEND_BLK = 0,
260 	VHOST_BACKEND_SCSI,
261 };
262 
263 struct spdk_vhost_dev_backend {
264 	enum vhost_backend_type type;
265 
266 	int (*vhost_get_config)(struct spdk_vhost_dev *vdev, uint8_t *config, uint32_t len);
267 	int (*vhost_set_config)(struct spdk_vhost_dev *vdev, uint8_t *config,
268 				uint32_t offset, uint32_t size, uint32_t flags);
269 
270 	void (*dump_info_json)(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
271 	void (*write_config_json)(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
272 	int (*remove_device)(struct spdk_vhost_dev *vdev);
273 	int (*set_coalescing)(struct spdk_vhost_dev *vdev, uint32_t delay_base_us,
274 			      uint32_t iops_threshold);
275 	void (*get_coalescing)(struct spdk_vhost_dev *vdev, uint32_t *delay_base_us,
276 			       uint32_t *iops_threshold);
277 };
278 
279 void *vhost_gpa_to_vva(struct spdk_vhost_session *vsession, uint64_t addr, uint64_t len);
280 
281 uint16_t vhost_vq_avail_ring_get(struct spdk_vhost_virtqueue *vq, uint16_t *reqs,
282 				 uint16_t reqs_len);
283 
284 /**
285  * Get a virtio split descriptor at given index in given virtqueue.
286  * The descriptor will provide access to the entire descriptor
287  * chain. The subsequent descriptors are accessible via
288  * \c spdk_vhost_vring_desc_get_next.
289  * \param vsession vhost session
290  * \param vq virtqueue
291  * \param req_idx descriptor index
292  * \param desc pointer to be set to the descriptor
293  * \param desc_table descriptor table to be used with
294  * \c spdk_vhost_vring_desc_get_next. This might be either
295  * default virtqueue descriptor table or per-chain indirect
296  * table.
297  * \param desc_table_size size of the *desc_table*
298  * \return 0 on success, -1 if given index is invalid.
299  * If -1 is returned, the content of params is undefined.
300  */
301 int vhost_vq_get_desc(struct spdk_vhost_session *vsession, struct spdk_vhost_virtqueue *vq,
302 		      uint16_t req_idx, struct vring_desc **desc, struct vring_desc **desc_table,
303 		      uint32_t *desc_table_size);
304 
305 /**
306  * Get a virtio packed descriptor at given index in given virtqueue.
307  * The descriptor will provide access to the entire descriptor
308  * chain. The subsequent descriptors are accessible via
309  * \c vhost_vring_packed_desc_get_next.
310  * \param vsession vhost session
311  * \param vq virtqueue
312  * \param req_idx descriptor index
313  * \param desc pointer to be set to the descriptor
314  * \param desc_table descriptor table to be used with
315  * \c spdk_vhost_vring_desc_get_next. This might be either
316  * \c NULL or per-chain indirect table.
317  * \param desc_table_size size of the *desc_table*
318  * \return 0 on success, -1 if given index is invalid.
319  * If -1 is returned, the content of params is undefined.
320  */
321 int vhost_vq_get_desc_packed(struct spdk_vhost_session *vsession,
322 			     struct spdk_vhost_virtqueue *virtqueue,
323 			     uint16_t req_idx, struct vring_packed_desc **desc,
324 			     struct vring_packed_desc **desc_table, uint32_t *desc_table_size);
325 
326 int vhost_inflight_queue_get_desc(struct spdk_vhost_session *vsession,
327 				  spdk_vhost_inflight_desc *desc_array,
328 				  uint16_t req_idx, spdk_vhost_inflight_desc **desc,
329 				  struct vring_packed_desc  **desc_table, uint32_t *desc_table_size);
330 
331 /**
332  * Send IRQ/call client (if pending) for \c vq.
333  * \param vsession vhost session
334  * \param vq virtqueue
335  * \return
336  *   0 - if no interrupt was signalled
337  *   1 - if interrupt was signalled
338  */
339 int vhost_vq_used_signal(struct spdk_vhost_session *vsession, struct spdk_vhost_virtqueue *vq);
340 
341 /**
342  * Send IRQs for the queue that need to be signaled.
343  * \param vq virtqueue
344  */
345 void vhost_session_vq_used_signal(struct spdk_vhost_virtqueue *virtqueue);
346 
347 void vhost_vq_used_ring_enqueue(struct spdk_vhost_session *vsession,
348 				struct spdk_vhost_virtqueue *vq,
349 				uint16_t id, uint32_t len);
350 
351 /**
352  * Enqueue the entry to the used ring when device complete the request.
353  * \param vsession vhost session
354  * \param vq virtqueue
355  * \req_idx descriptor index. It's the first index of this descriptor chain.
356  * \num_descs descriptor count. It's the count of the number of buffers in the chain.
357  * \buffer_id descriptor buffer ID.
358  * \length device write length. Specify the length of the buffer that has been initialized
359  * (written to) by the device
360  * \inflight_head the head idx of this IO inflight desc chain.
361  */
362 void vhost_vq_packed_ring_enqueue(struct spdk_vhost_session *vsession,
363 				  struct spdk_vhost_virtqueue *virtqueue,
364 				  uint16_t num_descs, uint16_t buffer_id,
365 				  uint32_t length, uint16_t inflight_head);
366 
367 /**
368  * Get subsequent descriptor from given table.
369  * \param desc current descriptor, will be set to the
370  * next descriptor (NULL in case this is the last
371  * descriptor in the chain or the next desc is invalid)
372  * \param desc_table descriptor table
373  * \param desc_table_size size of the *desc_table*
374  * \return 0 on success, -1 if given index is invalid
375  * The *desc* param will be set regardless of the
376  * return value.
377  */
378 int vhost_vring_desc_get_next(struct vring_desc **desc,
379 			      struct vring_desc *desc_table, uint32_t desc_table_size);
380 static inline bool
381 vhost_vring_desc_is_wr(struct vring_desc *cur_desc)
382 {
383 	return !!(cur_desc->flags & VRING_DESC_F_WRITE);
384 }
385 
386 int vhost_vring_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
387 			    uint16_t *iov_index, const struct vring_desc *desc);
388 
389 bool vhost_vq_packed_ring_is_avail(struct spdk_vhost_virtqueue *virtqueue);
390 
391 /**
392  * Get subsequent descriptor from vq or desc table.
393  * \param desc current descriptor, will be set to the
394  * next descriptor (NULL in case this is the last
395  * descriptor in the chain or the next desc is invalid)
396  * \req_idx index of current desc, will be set to the next
397  * index. If desc_table != NULL the req_idx is the the vring index
398  * or the req_idx is the desc_table index.
399  * \param desc_table descriptor table
400  * \param desc_table_size size of the *desc_table*
401  * \return 0 on success, -1 if given index is invalid
402  * The *desc* param will be set regardless of the
403  * return value.
404  */
405 int vhost_vring_packed_desc_get_next(struct vring_packed_desc **desc, uint16_t *req_idx,
406 				     struct spdk_vhost_virtqueue *vq,
407 				     struct vring_packed_desc *desc_table,
408 				     uint32_t desc_table_size);
409 
410 bool vhost_vring_packed_desc_is_wr(struct vring_packed_desc *cur_desc);
411 
412 int vhost_vring_packed_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
413 				   uint16_t *iov_index, const struct vring_packed_desc *desc);
414 
415 bool vhost_vring_inflight_desc_is_wr(spdk_vhost_inflight_desc *cur_desc);
416 
417 int vhost_vring_inflight_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
418 				     uint16_t *iov_index, const spdk_vhost_inflight_desc *desc);
419 
420 uint16_t vhost_vring_packed_desc_get_buffer_id(struct spdk_vhost_virtqueue *vq, uint16_t req_idx,
421 		uint16_t *num_descs);
422 
423 static inline bool
424 __attribute__((always_inline))
425 vhost_dev_has_feature(struct spdk_vhost_session *vsession, unsigned feature_id)
426 {
427 	return vsession->negotiated_features & (1ULL << feature_id);
428 }
429 
430 int vhost_scsi_controller_start(const char *name);
431 
432 int vhost_dev_register(struct spdk_vhost_dev *vdev, const char *name, const char *mask_str,
433 		       const struct spdk_json_val *params, const struct spdk_vhost_dev_backend *backend,
434 		       const struct spdk_vhost_user_dev_backend *user_backend, bool delay);
435 
436 int vhost_dev_unregister(struct spdk_vhost_dev *vdev);
437 
438 void vhost_dump_info_json(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
439 
440 /*
441  * Set vhost session to run in interrupt or poll mode
442  */
443 void vhost_user_session_set_interrupt_mode(struct spdk_vhost_session *vsession,
444 		bool interrupt_mode);
445 
446 /*
447  * Memory registration functions used in start/stop device callbacks
448  */
449 void vhost_session_mem_register(struct rte_vhost_memory *mem);
450 void vhost_session_mem_unregister(struct rte_vhost_memory *mem);
451 
452 /*
453  * Call a function for each session of the provided vhost device.
454  * The function will be called one-by-one on each session's thread.
455  *
456  * \param vdev vhost device
457  * \param fn function to call on each session's thread
458  * \param cpl_fn function to be called at the end of the iteration on
459  * the vhost management thread.
460  * Optional, can be NULL.
461  * \param arg additional argument to the both callbacks
462  */
463 void vhost_user_dev_foreach_session(struct spdk_vhost_dev *dev,
464 				    spdk_vhost_session_fn fn,
465 				    spdk_vhost_dev_fn cpl_fn,
466 				    void *arg);
467 
468 /**
469  * Finish a blocking vhost_user_wait_for_session_stop() call and finally
470  * stop the session. This must be called on the session's lcore which
471  * used to receive all session-related messages (e.g. from
472  * vhost_user_dev_foreach_session()). After this call, the session-
473  * related messages will be once again processed by any arbitrary thread.
474  *
475  * Must be called under the vhost user device's session access lock.
476  *
477  * \param vsession vhost session
478  * \param response return code
479  */
480 void vhost_user_session_stop_done(struct spdk_vhost_session *vsession, int response);
481 
482 struct spdk_vhost_session *vhost_session_find_by_vid(int vid);
483 void vhost_session_install_rte_compat_hooks(struct spdk_vhost_session *vsession);
484 int vhost_register_unix_socket(const char *path, const char *ctrl_name,
485 			       uint64_t virtio_features, uint64_t disabled_features, uint64_t protocol_features);
486 int vhost_driver_unregister(const char *path);
487 int vhost_get_mem_table(int vid, struct rte_vhost_memory **mem);
488 int vhost_get_negotiated_features(int vid, uint64_t *negotiated_features);
489 
490 int remove_vhost_controller(struct spdk_vhost_dev *vdev);
491 
492 struct spdk_io_channel *vhost_blk_get_io_channel(struct spdk_vhost_dev *vdev);
493 void vhost_blk_put_io_channel(struct spdk_io_channel *ch);
494 
495 /* The spdk_bdev pointer should only be used to retrieve
496  * the device properties, ex. number of blocks or I/O type supported. */
497 struct spdk_bdev *vhost_blk_get_bdev(struct spdk_vhost_dev *vdev);
498 
499 /* Function calls from vhost.c to rte_vhost_user.c,
500  * shall removed once virtio transport abstraction is complete. */
501 int vhost_user_session_set_coalescing(struct spdk_vhost_dev *dev,
502 				      struct spdk_vhost_session *vsession, void *ctx);
503 int vhost_user_dev_set_coalescing(struct spdk_vhost_user_dev *user_dev, uint32_t delay_base_us,
504 				  uint32_t iops_threshold);
505 int vhost_user_dev_create(struct spdk_vhost_dev *vdev, const char *name,
506 			  struct spdk_cpuset *cpumask,
507 			  const struct spdk_vhost_user_dev_backend *user_backend, bool dealy);
508 int vhost_user_dev_init(struct spdk_vhost_dev *vdev, const char *name,
509 			struct spdk_cpuset *cpumask, const struct spdk_vhost_user_dev_backend *user_backend);
510 int vhost_user_dev_start(struct spdk_vhost_dev *vdev);
511 int vhost_user_dev_unregister(struct spdk_vhost_dev *vdev);
512 int vhost_user_init(void);
513 void vhost_user_fini(spdk_vhost_fini_cb vhost_cb);
514 int vhost_user_set_coalescing(struct spdk_vhost_dev *vdev, uint32_t delay_base_us,
515 			      uint32_t iops_threshold);
516 void vhost_user_get_coalescing(struct spdk_vhost_dev *vdev, uint32_t *delay_base_us,
517 			       uint32_t *iops_threshold);
518 
519 int virtio_blk_construct_ctrlr(struct spdk_vhost_dev *vdev, const char *address,
520 			       struct spdk_cpuset *cpumask, const struct spdk_json_val *params,
521 			       const struct spdk_vhost_user_dev_backend *user_backend);
522 int virtio_blk_destroy_ctrlr(struct spdk_vhost_dev *vdev);
523 
524 struct spdk_vhost_blk_task;
525 
526 typedef void (*virtio_blk_request_cb)(uint8_t status, struct spdk_vhost_blk_task *task,
527 				      void *cb_arg);
528 
529 struct spdk_vhost_blk_task {
530 	struct spdk_bdev_io *bdev_io;
531 	virtio_blk_request_cb cb;
532 	void *cb_arg;
533 
534 	volatile uint8_t *status;
535 
536 	/* for io wait */
537 	struct spdk_bdev_io_wait_entry bdev_io_wait;
538 	struct spdk_io_channel *bdev_io_wait_ch;
539 	struct spdk_vhost_dev *bdev_io_wait_vdev;
540 
541 	/** Number of bytes that were written. */
542 	uint32_t used_len;
543 	uint16_t iovcnt;
544 	struct iovec iovs[SPDK_VHOST_IOVS_MAX];
545 
546 	/** Size of whole payload in bytes */
547 	uint32_t payload_size;
548 };
549 
550 int virtio_blk_process_request(struct spdk_vhost_dev *vdev, struct spdk_io_channel *ch,
551 			       struct spdk_vhost_blk_task *task, virtio_blk_request_cb cb, void *cb_arg);
552 
553 typedef void (*bdev_event_cb_complete)(struct spdk_vhost_dev *vdev, void *ctx);
554 
555 #define SPDK_VIRTIO_BLK_TRSTRING_MAX_LEN 32
556 
557 struct spdk_virtio_blk_transport_ops {
558 	/**
559 	 * Transport name
560 	 */
561 	char name[SPDK_VIRTIO_BLK_TRSTRING_MAX_LEN];
562 
563 	/**
564 	 * Create a transport for the given transport opts
565 	 */
566 	struct spdk_virtio_blk_transport *(*create)(const struct spdk_json_val *params);
567 
568 	/**
569 	 * Dump transport-specific opts into JSON
570 	 */
571 	void (*dump_opts)(struct spdk_virtio_blk_transport *transport, struct spdk_json_write_ctx *w);
572 
573 	/**
574 	 * Destroy the transport
575 	 */
576 	int (*destroy)(struct spdk_virtio_blk_transport *transport,
577 		       spdk_vhost_fini_cb cb_fn);
578 
579 	/**
580 	 * Create vhost block controller
581 	 */
582 	int (*create_ctrlr)(struct spdk_vhost_dev *vdev, struct spdk_cpuset *cpumask,
583 			    const char *address, const struct spdk_json_val *params,
584 			    void *custom_opts);
585 
586 	/**
587 	 * Destroy vhost block controller
588 	 */
589 	int (*destroy_ctrlr)(struct spdk_vhost_dev *vdev);
590 
591 	/*
592 	 * Signal removal of the bdev.
593 	 */
594 	void (*bdev_event)(enum spdk_bdev_event_type type, struct spdk_vhost_dev *vdev,
595 			   bdev_event_cb_complete cb, void *cb_arg);
596 
597 	/**
598 	 * Set coalescing parameters.
599 	 */
600 	int (*set_coalescing)(struct spdk_vhost_dev *vdev, uint32_t delay_base_us,
601 			      uint32_t iops_threshold);
602 
603 	/**
604 	 * Get coalescing parameters.
605 	 */
606 	void (*get_coalescing)(struct spdk_vhost_dev *vdev, uint32_t *delay_base_us,
607 			       uint32_t *iops_threshold);
608 };
609 
610 struct spdk_virtio_blk_transport {
611 	const struct spdk_virtio_blk_transport_ops	*ops;
612 	TAILQ_ENTRY(spdk_virtio_blk_transport)		tailq;
613 };
614 
615 struct virtio_blk_transport_ops_list_element {
616 	struct spdk_virtio_blk_transport_ops			ops;
617 	TAILQ_ENTRY(virtio_blk_transport_ops_list_element)	link;
618 };
619 
620 void virtio_blk_transport_register(const struct spdk_virtio_blk_transport_ops *ops);
621 int virtio_blk_transport_create(const char *transport_name, const struct spdk_json_val *params);
622 int virtio_blk_transport_destroy(struct spdk_virtio_blk_transport *transport,
623 				 spdk_vhost_fini_cb cb_fn);
624 struct spdk_virtio_blk_transport *virtio_blk_transport_get_first(void);
625 struct spdk_virtio_blk_transport *virtio_blk_transport_get_next(
626 	struct spdk_virtio_blk_transport *transport);
627 void virtio_blk_transport_dump_opts(struct spdk_virtio_blk_transport *transport,
628 				    struct spdk_json_write_ctx *w);
629 struct spdk_virtio_blk_transport *virtio_blk_tgt_get_transport(const char *transport_name);
630 const struct spdk_virtio_blk_transport_ops *virtio_blk_get_transport_ops(
631 	const char *transport_name);
632 
633 void vhost_session_info_json(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
634 
635 /*
636  * Macro used to register new transports.
637  */
638 #define SPDK_VIRTIO_BLK_TRANSPORT_REGISTER(name, transport_ops) \
639 static void __attribute__((constructor)) _virtio_blk_transport_register_##name(void) \
640 { \
641 	virtio_blk_transport_register(transport_ops); \
642 }
643 
644 #endif /* SPDK_VHOST_INTERNAL_H */
645