summaryrefslogtreecommitdiffstats
path: root/include/linux/virtio_config.h
blob: 2b3438de2c4d4e887bdfbf89f5c137f3218b00e9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_VIRTIO_CONFIG_H
#define _LINUX_VIRTIO_CONFIG_H

#include <linux/err.h>
#include <linux/bug.h>
#include <linux/virtio.h>
#include <linux/virtio_byteorder.h>
#include <linux/compiler_types.h>
#include <uapi/linux/virtio_config.h>

struct irq_affinity;

struct virtio_shm_region {
	u64 addr;
	u64 len;
};

typedef void vq_callback_t(struct virtqueue *);

/**
 * struct virtio_config_ops - operations for configuring a virtio device
 * Note: Do not assume that a transport implements all of the operations
 *       getting/setting a value as a simple read/write! Generally speaking,
 *       any of @get/@set, @get_status/@set_status, or @get_features/
 *       @finalize_features are NOT safe to be called from an atomic
 *       context.
 * @get: read the value of a configuration field
 *	vdev: the virtio_device
 *	offset: the offset of the configuration field
 *	buf: the buffer to write the field value into.
 *	len: the length of the buffer
 * @set: write the value of a configuration field
 *	vdev: the virtio_device
 *	offset: the offset of the configuration field
 *	buf: the buffer to read the field value from.
 *	len: the length of the buffer
 * @generation: config generation counter (optional)
 *	vdev: the virtio_device
 *	Returns the config generation counter
 * @get_status: read the status byte
 *	vdev: the virtio_device
 *	Returns the status byte
 * @set_status: write the status byte
 *	vdev: the virtio_device
 *	status: the new status byte
 * @reset: reset the device
 *	vdev: the virtio device
 *	After this, status and feature negotiation must be done again
 *	Device must not be reset from its vq/config callbacks, or in
 *	parallel with being added/removed.
 * @find_vqs: find virtqueues and instantiate them.
 *	vdev: the virtio_device
 *	nvqs: the number of virtqueues to find
 *	vqs: on success, includes new virtqueues
 *	callbacks: array of callbacks, for each virtqueue
 *		include a NULL entry for vqs that do not need a callback
 *	names: array of virtqueue names (mainly for debugging)
 *		include a NULL entry for vqs unused by driver
 *	Returns 0 on success or error status
 * @del_vqs: free virtqueues found by find_vqs().
 * @synchronize_cbs: synchronize with the virtqueue callbacks (optional)
 *      The function guarantees that all memory operations on the
 *      queue before it are visible to the vring_interrupt() that is
 *      called after it.
 *      vdev: the virtio_device
 * @get_features: get the array of feature bits for this device.
 *	vdev: the virtio_device
 *	Returns the first 64 feature bits (all we currently need).
 * @finalize_features: confirm what device features we'll be using.
 *	vdev: the virtio_device
 *	This sends the driver feature bits to the device: it can change
 *	the dev->feature bits if it wants.
 *	Note that despite the name this	can be called any number of
 *	times.
 *	Returns 0 on success or error status
 * @bus_name: return the bus name associated with the device (optional)
 *	vdev: the virtio_device
 *      This returns a pointer to the bus name a la pci_name from which
 *      the caller can then copy.
 * @set_vq_affinity: set the affinity for a virtqueue (optional).
 * @get_vq_affinity: get the affinity for a virtqueue (optional).
 * @get_shm_region: get a shared memory region based on the index.
 * @disable_vq_and_reset: reset a queue individually (optional).
 *	vq: the virtqueue
 *	Returns 0 on success or error status
 *	disable_vq_and_reset will guarantee that the callbacks are disabled and
 *	synchronized.
 *	Except for the callback, the caller should guarantee that the vring is
 *	not accessed by any functions of virtqueue.
 * @enable_vq_after_reset: enable a reset queue
 *	vq: the virtqueue
 *	Returns 0 on success or error status
 *	If disable_vq_and_reset is set, then enable_vq_after_reset must also be
 *	set.
 */
struct virtio_config_ops {
	void (*get)(struct virtio_device *vdev, unsigned offset,
		    void *buf, unsigned len);
	void (*set)(struct virtio_device *vdev, unsigned offset,
		    const void *buf, unsigned len);
	u32 (*generation)(struct virtio_device *vdev);
	u8 (*get_status)(struct virtio_device *vdev);
	void (*set_status)(struct virtio_device *vdev, u8 status);
	void (*reset)(struct virtio_device *vdev);
	int (*find_vqs)(struct virtio_device *, unsigned nvqs,
			struct virtqueue *vqs[], vq_callback_t *callbacks[],
			const char * const names[], const bool *ctx,
			struct irq_affinity *desc);
	void (*del_vqs)(struct virtio_device *);
	void (*synchronize_cbs)(struct virtio_device *);
	u64 (*get_features)(struct virtio_device *vdev);
	int (*finalize_features)(struct virtio_device *vdev);
	const char *(*bus_name)(struct virtio_device *vdev);
	int (*set_vq_affinity)(struct virtqueue *vq,
			       const struct cpumask *cpu_mask);
	const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
			int index);
	bool (*get_shm_region)(struct virtio_device *vdev,
			       struct virtio_shm_region *region, u8 id);
	int (*disable_vq_and_reset)(struct virtqueue *vq);
	int (*enable_vq_after_reset)(struct virtqueue *vq);
};

/* If driver didn't advertise the feature, it will never appear. */
void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
					 unsigned int fbit);

/**
 * __virtio_test_bit - helper to test feature bits. For use by transports.
 *                     Devices should normally use virtio_has_feature,
 *                     which includes more checks.
 * @vdev: the device
 * @fbit: the feature bit
 */
static inline bool __virtio_test_bit(const struct virtio_device *vdev,
				     unsigned int fbit)
{
	/* Did you forget to fix assumptions on max features? */
	if (__builtin_constant_p(fbit))
		BUILD_BUG_ON(fbit >= 64);
	else
		BUG_ON(fbit >= 64);

	return vdev->features & BIT_ULL(fbit);
}

/**
 * __virtio_set_bit - helper to set feature bits. For use by transports.
 * @vdev: the device
 * @fbit: the feature bit
 */
static inline void __virtio_set_bit(struct virtio_device *vdev,
				    unsigned int fbit)
{
	/* Did you forget to fix assumptions on max features? */
	if (__builtin_constant_p(fbit))
		BUILD_BUG_ON(fbit >= 64);
	else
		BUG_ON(fbit >= 64);

	vdev->features |= BIT_ULL(fbit);
}

/**
 * __virtio_clear_bit - helper to clear feature bits. For use by transports.
 * @vdev: the device
 * @fbit: the feature bit
 */
static inline void __virtio_clear_bit(struct virtio_device *vdev,
				      unsigned int fbit)
{
	/* Did you forget to fix assumptions on max features? */
	if (__builtin_constant_p(fbit))
		BUILD_BUG_ON(fbit >= 64);
	else
		BUG_ON(fbit >= 64);

	vdev->features &= ~BIT_ULL(fbit);
}

/**
 * virtio_has_feature - helper to determine if this device has this feature.
 * @vdev: the device
 * @fbit: the feature bit
 */
static inline bool virtio_has_feature(const struct virtio_device *vdev,
				      unsigned int fbit)
{
	if (fbit < VIRTIO_TRANSPORT_F_START)
		virtio_check_driver_offered_feature(vdev, fbit);

	return __virtio_test_bit(vdev, fbit);
}

/**
 * virtio_has_dma_quirk - determine whether this device has the DMA quirk
 * @vdev: the device
 */
static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev)
{
	/*
	 * Note the reverse polarity of the quirk feature (compared to most
	 * other features), this is for compatibility with legacy systems.
	 */
	return !virtio_has_feature(vdev, VIRTIO_F_ACCESS_PLATFORM);
}

static inline
struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
					vq_callback_t *c, const char *n)
{
	vq_callback_t *callbacks[] = { c };
	const char *names[] = { n };
	struct virtqueue *vq;
	int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL,
					 NULL);
	if (err < 0)
		return ERR_PTR(err);
	return vq;
}

static inline
int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
			struct virtqueue *vqs[], vq_callback_t *callbacks[],
			const char * const names[],
			struct irq_affinity *desc)
{
	return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, desc);
}

static inline
int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs,
			struct virtqueue *vqs[], vq_callback_t *callbacks[],
			const char * const names[], const bool *ctx,
			struct irq_affinity *desc)
{
	return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, ctx,
				      desc);
}

/**
 * virtio_synchronize_cbs - synchronize with virtqueue callbacks
 * @dev: the virtio device
 */
static inline
void virtio_synchronize_cbs(struct virtio_device *dev)
{
	if (dev->config->synchronize_cbs) {
		dev->config->synchronize_cbs(dev);
	} else {
		/*
		 * A best effort fallback to synchronize with
		 * interrupts, preemption and softirq disabled
		 * regions. See comment above synchronize_rcu().
		 */
		synchronize_rcu();
	}
}

/**
 * virtio_device_ready - enable vq use in probe function
 * @dev: the virtio device
 *
 * Driver must call this to use vqs in the probe function.
 *
 * Note: vqs are enabled automatically after probe returns.
 */
static inline
void virtio_device_ready(struct virtio_device *dev)
{
	unsigned status = dev->config->get_status(dev);

	WARN_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);

#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
	/*
	 * The virtio_synchronize_cbs() makes sure vring_interrupt()
	 * will see the driver specific setup if it sees vq->broken
	 * as false (even if the notifications come before DRIVER_OK).
	 */
	virtio_synchronize_cbs(dev);
	__virtio_unbreak_device(dev);
#endif
	/*
	 * The transport should ensure the visibility of vq->broken
	 * before setting DRIVER_OK. See the comments for the transport
	 * specific set_status() method.
	 *
	 * A well behaved device will only notify a virtqueue after
	 * DRIVER_OK, this means the device should "see" the coherenct
	 * memory write that set vq->broken as false which is done by
	 * the driver when it sees DRIVER_OK, then the following
	 * driver's vring_interrupt() will see vq->broken as false so
	 * we won't lose any notification.
	 */
	dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
}

static inline
const char *virtio_bus_name(struct virtio_device *vdev)
{
	if (!vdev->config->bus_name)
		return "virtio";
	return vdev->config->bus_name(vdev);
}

/**
 * virtqueue_set_affinity - setting affinity for a virtqueue
 * @vq: the virtqueue
 * @cpu_mask: the cpu mask
 *
 * Pay attention the function are best-effort: the affinity hint may not be set
 * due to config support, irq type and sharing.
 *
 */
static inline
int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
{
	struct virtio_device *vdev = vq->vdev;
	if (vdev->config->set_vq_affinity)
		return vdev->config->set_vq_affinity(vq, cpu_mask);
	return 0;
}

static inline
bool virtio_get_shm_region(struct virtio_device *vdev,
			   struct virtio_shm_region *region, u8 id)
{
	if (!vdev->config->get_shm_region)
		return false;
	return vdev->config->get_shm_region(vdev, region, id);
}

static inline bool virtio_is_little_endian(struct virtio_device *vdev)
{
	return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
		virtio_legacy_is_little_endian();
}

/* Memory accessors */
static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
{
	return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
}

static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
{
	return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
}

static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
{
	return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
}

static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
{
	return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
}

static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
{
	return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
}

static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
{
	return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
}

#define virtio_to_cpu(vdev, x) \
	_Generic((x), \
		__u8: (x), \
		__virtio16: virtio16_to_cpu((vdev), (x)), \
		__virtio32: virtio32_to_cpu((vdev), (x)), \
		__virtio64: virtio64_to_cpu((vdev), (x)) \
		)

#define cpu_to_virtio(vdev, x, m) \
	_Generic((m), \
		__u8: (x), \
		__virtio16: cpu_to_virtio16((vdev), (x)), \
		__virtio32: cpu_to_virtio32((vdev), (x)), \
		__virtio64: cpu_to_virtio64((vdev), (x)) \
		)

#define __virtio_native_type(structname, member) \
	typeof(virtio_to_cpu(NULL, ((structname*)0)->member))

/* Config space accessors. */
#define virtio_cread(vdev, structname, member, ptr)			\
	do {								\
		typeof(((structname*)0)->member) virtio_cread_v;	\
									\
		might_sleep();						\
		/* Sanity check: must match the member's type */	\
		typecheck(typeof(virtio_to_cpu((vdev), virtio_cread_v)), *(ptr)); \
									\
		switch (sizeof(virtio_cread_v)) {			\
		case 1:							\
		case 2:							\
		case 4:							\
			vdev->config->get((vdev), 			\
					  offsetof(structname, member), \
					  &virtio_cread_v,		\
					  sizeof(virtio_cread_v));	\
			break;						\
		default:						\
			__virtio_cread_many((vdev), 			\
					  offsetof(structname, member), \
					  &virtio_cread_v,		\
					  1,				\
					  sizeof(virtio_cread_v));	\
			break;						\
		}							\
		*(ptr) = virtio_to_cpu(vdev, virtio_cread_v);		\
	} while(0)

/* Config space accessors. */
#define virtio_cwrite(vdev, structname, member, ptr)			\
	do {								\
		typeof(((structname*)0)->member) virtio_cwrite_v =	\
			cpu_to_virtio(vdev, *(ptr), ((structname*)0)->member); \
									\
		might_sleep();						\
		/* Sanity check: must match the member's type */	\
		typecheck(typeof(virtio_to_cpu((vdev), virtio_cwrite_v)), *(ptr)); \
									\
		vdev->config->set((vdev), offsetof(structname, member),	\
				  &virtio_cwrite_v,			\
				  sizeof(virtio_cwrite_v));		\
	} while(0)

/*
 * Nothing virtio-specific about these, but let's worry about generalizing
 * these later.
 */
#define virtio_le_to_cpu(x) \
	_Generic((x), \
		__u8: (u8)(x), \
		 __le16: (u16)le16_to_cpu(x), \
		 __le32: (u32)le32_to_cpu(x), \
		 __le64: (u64)le64_to_cpu(x) \
		)

#define virtio_cpu_to_le(x, m) \
	_Generic((m), \
		 __u8: (x), \
		 __le16: cpu_to_le16(x), \
		 __le32: cpu_to_le32(x), \
		 __le64: cpu_to_le64(x) \
		)

/* LE (e.g. modern) Config space accessors. */
#define virtio_cread_le(vdev, structname, member, ptr)			\
	do {								\
		typeof(((structname*)0)->member) virtio_cread_v;	\
									\
		might_sleep();						\
		/* Sanity check: must match the member's type */	\
		typecheck(typeof(virtio_le_to_cpu(virtio_cread_v)), *(ptr)); \
									\
		switch (sizeof(virtio_cread_v)) {			\
		case 1:							\
		case 2:							\
		case 4:							\
			vdev->config->get((vdev), 			\
					  offsetof(structname, member), \
					  &virtio_cread_v,		\
					  sizeof(virtio_cread_v));	\
			break;						\
		default:						\
			__virtio_cread_many((vdev), 			\
					  offsetof(structname, member), \
					  &virtio_cread_v,		\
					  1,				\
					  sizeof(virtio_cread_v));	\
			break;						\
		}							\
		*(ptr) = virtio_le_to_cpu(virtio_cread_v);		\
	} while(0)

#define virtio_cwrite_le(vdev, structname, member, ptr)			\
	do {								\
		typeof(((structname*)0)->member) virtio_cwrite_v =	\
			virtio_cpu_to_le(*(ptr), ((structname*)0)->member); \
									\
		might_sleep();						\
		/* Sanity check: must match the member's type */	\
		typecheck(typeof(virtio_le_to_cpu(virtio_cwrite_v)), *(ptr)); \
									\
		vdev->config->set((vdev), offsetof(structname, member),	\
				  &virtio_cwrite_v,			\
				  sizeof(virtio_cwrite_v));		\
	} while(0)


/* Read @count fields, @bytes each. */
static inline void __virtio_cread_many(struct virtio_device *vdev,
				       unsigned int offset,
				       void *buf, size_t count, size_t bytes)
{
	u32 old, gen = vdev->config->generation ?
		vdev->config->generation(vdev) : 0;
	int i;

	might_sleep();
	do {
		old = gen;

		for (i = 0; i < count; i++)
			vdev->config->get(vdev, offset + bytes * i,
					  buf + i * bytes, bytes);

		gen = vdev->config->generation ?
			vdev->config->generation(vdev) : 0;
	} while (gen != old);
}

static inline void virtio_cread_bytes(struct virtio_device *vdev,
				      unsigned int offset,
				      void *buf, size_t len)
{
	__virtio_cread_many(vdev, offset, buf, len, 1);
}

static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
{
	u8 ret;

	might_sleep();
	vdev->config->get(vdev, offset, &ret, sizeof(ret));
	return ret;
}

static inline void virtio_cwrite8(struct virtio_device *vdev,
				  unsigned int offset, u8 val)
{
	might_sleep();
	vdev->config->set(vdev, offset, &val, sizeof(val));
}

static inline u16 virtio_cread16(struct virtio_device *vdev,
				 unsigned int offset)
{
	__virtio16 ret;

	might_sleep();
	vdev->config->get(vdev, offset, &ret, sizeof(ret));
	return virtio16_to_cpu(vdev, ret);
}

static inline void virtio_cwrite16(struct virtio_device *vdev,
				   unsigned int offset, u16 val)
{
	__virtio16 v;

	might_sleep();
	v = cpu_to_virtio16(vdev, val);
	vdev->config->set(vdev, offset, &v, sizeof(v));
}

static inline u32 virtio_cread32(struct virtio_device *vdev,
				 unsigned int offset)
{
	__virtio32 ret;

	might_sleep();
	vdev->config->get(vdev, offset, &ret, sizeof(ret));
	return virtio32_to_cpu(vdev, ret);
}

static inline void virtio_cwrite32(struct virtio_device *vdev,
				   unsigned int offset, u32 val)
{
	__virtio32 v;

	might_sleep();
	v = cpu_to_virtio32(vdev, val);
	vdev->config->set(vdev, offset, &v, sizeof(v));
}

static inline u64 virtio_cread64(struct virtio_device *vdev,
				 unsigned int offset)
{
	__virtio64 ret;

	__virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
	return virtio64_to_cpu(vdev, ret);
}

static inline void virtio_cwrite64(struct virtio_device *vdev,
				   unsigned int offset, u64 val)
{
	__virtio64 v;

	might_sleep();
	v = cpu_to_virtio64(vdev, val);
	vdev->config->set(vdev, offset, &v, sizeof(v));
}

/* Conditional config space accessors. */
#define virtio_cread_feature(vdev, fbit, structname, member, ptr)	\
	({								\
		int _r = 0;						\
		if (!virtio_has_feature(vdev, fbit))			\
			_r = -ENOENT;					\
		else							\
			virtio_cread((vdev), structname, member, ptr);	\
		_r;							\
	})

/* Conditional config space accessors. */
#define virtio_cread_le_feature(vdev, fbit, structname, member, ptr)	\
	({								\
		int _r = 0;						\
		if (!virtio_has_feature(vdev, fbit))			\
			_r = -ENOENT;					\
		else							\
			virtio_cread_le((vdev), structname, member, ptr); \
		_r;							\
	})

#endif /* _LINUX_VIRTIO_CONFIG_H */