summaryrefslogtreecommitdiffstats
path: root/drivers/vhost/vhost.h
blob: 1647b750169c79363b8e9ea3ac9c667d0af6af69 (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
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _VHOST_H
#define _VHOST_H

#include <linux/eventfd.h>
#include <linux/vhost.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/virtio_config.h>
#include <linux/virtio_ring.h>
#include <linux/atomic.h>
#include <linux/vhost_iotlb.h>
#include <linux/irqbypass.h>

struct vhost_work;
typedef void (*vhost_work_fn_t)(struct vhost_work *work);

#define VHOST_WORK_QUEUED 1
struct vhost_work {
	struct llist_node	node;
	vhost_work_fn_t		fn;
	unsigned long		flags;
};

/* Poll a file (eventfd or socket) */
/* Note: there's nothing vhost specific about this structure. */
struct vhost_poll {
	poll_table		table;
	wait_queue_head_t	*wqh;
	wait_queue_entry_t	wait;
	struct vhost_work	work;
	__poll_t		mask;
	struct vhost_dev	*dev;
};

void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
bool vhost_has_work(struct vhost_dev *dev);

void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
		     __poll_t mask, struct vhost_dev *dev);
int vhost_poll_start(struct vhost_poll *poll, struct file *file);
void vhost_poll_stop(struct vhost_poll *poll);
void vhost_poll_queue(struct vhost_poll *poll);
void vhost_dev_flush(struct vhost_dev *dev);

struct vhost_log {
	u64 addr;
	u64 len;
};

enum vhost_uaddr_type {
	VHOST_ADDR_DESC = 0,
	VHOST_ADDR_AVAIL = 1,
	VHOST_ADDR_USED = 2,
	VHOST_NUM_ADDRS = 3,
};

struct vhost_vring_call {
	struct eventfd_ctx *ctx;
	struct irq_bypass_producer producer;
};

/* The virtqueue structure describes a queue attached to a device. */
struct vhost_virtqueue {
	struct vhost_dev *dev;

	/* The actual ring of buffers. */
	struct mutex mutex;
	unsigned int num;
	vring_desc_t __user *desc;
	vring_avail_t __user *avail;
	vring_used_t __user *used;
	const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
	struct file *kick;
	struct vhost_vring_call call_ctx;
	struct eventfd_ctx *error_ctx;
	struct eventfd_ctx *log_ctx;

	struct vhost_poll poll;

	/* The routine to call when the Guest pings us, or timeout. */
	vhost_work_fn_t handle_kick;

	/* Last available index we saw. */
	u16 last_avail_idx;

	/* Caches available index value from user. */
	u16 avail_idx;

	/* Last index we used. */
	u16 last_used_idx;

	/* Used flags */
	u16 used_flags;

	/* Last used index value we have signalled on */
	u16 signalled_used;

	/* Last used index value we have signalled on */
	bool signalled_used_valid;

	/* Log writes to used structure. */
	bool log_used;
	u64 log_addr;

	struct iovec iov[UIO_MAXIOV];
	struct iovec iotlb_iov[64];
	struct iovec *indirect;
	struct vring_used_elem *heads;
	/* Protected by virtqueue mutex. */
	struct vhost_iotlb *umem;
	struct vhost_iotlb *iotlb;
	void *private_data;
	u64 acked_features;
	u64 acked_backend_features;
	/* Log write descriptors */
	void __user *log_base;
	struct vhost_log *log;
	struct iovec log_iov[64];

	/* Ring endianness. Defaults to legacy native endianness.
	 * Set to true when starting a modern virtio device. */
	bool is_le;
#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
	/* Ring endianness requested by userspace for cross-endian support. */
	bool user_be;
#endif
	u32 busyloop_timeout;
};

struct vhost_msg_node {
  union {
	  struct vhost_msg msg;
	  struct vhost_msg_v2 msg_v2;
  };
  struct vhost_virtqueue *vq;
  struct list_head node;
};

struct vhost_dev {
	struct mm_struct *mm;
	struct mutex mutex;
	struct vhost_virtqueue **vqs;
	int nvqs;
	struct eventfd_ctx *log_ctx;
	struct llist_head work_list;
	struct task_struct *worker;
	struct vhost_iotlb *umem;
	struct vhost_iotlb *iotlb;
	spinlock_t iotlb_lock;
	struct list_head read_list;
	struct list_head pending_list;
	wait_queue_head_t wait;
	int iov_limit;
	int weight;
	int byte_weight;
	u64 kcov_handle;
	bool use_worker;
	int (*msg_handler)(struct vhost_dev *dev, u32 asid,
			   struct vhost_iotlb_msg *msg);
};

bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
		    int nvqs, int iov_limit, int weight, int byte_weight,
		    bool use_worker,
		    int (*msg_handler)(struct vhost_dev *dev, u32 asid,
				       struct vhost_iotlb_msg *msg));
long vhost_dev_set_owner(struct vhost_dev *dev);
bool vhost_dev_has_owner(struct vhost_dev *dev);
long vhost_dev_check_owner(struct vhost_dev *);
struct vhost_iotlb *vhost_dev_reset_owner_prepare(void);
void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *iotlb);
void vhost_dev_cleanup(struct vhost_dev *);
void vhost_dev_stop(struct vhost_dev *);
long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
bool vhost_log_access_ok(struct vhost_dev *);
void vhost_clear_msg(struct vhost_dev *dev);

int vhost_get_vq_desc(struct vhost_virtqueue *,
		      struct iovec iov[], unsigned int iov_count,
		      unsigned int *out_num, unsigned int *in_num,
		      struct vhost_log *log, unsigned int *log_num);
void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);

bool vhost_vq_is_setup(struct vhost_virtqueue *vq);
int vhost_vq_init_access(struct vhost_virtqueue *);
int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
		     unsigned count);
void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
			       unsigned int id, int len);
void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
			       struct vring_used_elem *heads, unsigned count);
void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);

int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
		    unsigned int log_num, u64 len,
		    struct iovec *iov, int count);
int vq_meta_prefetch(struct vhost_virtqueue *vq);

struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
void vhost_enqueue_msg(struct vhost_dev *dev,
		       struct list_head *head,
		       struct vhost_msg_node *node);
struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
					 struct list_head *head);
void vhost_set_backend_features(struct vhost_dev *dev, u64 features);

__poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
			    poll_table *wait);
ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
			    int noblock);
ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
			     struct iov_iter *from);
int vhost_init_device_iotlb(struct vhost_dev *d);

void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
			  struct vhost_iotlb_map *map);

#define vq_err(vq, fmt, ...) do {                                  \
		pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
		if ((vq)->error_ctx)                               \
				eventfd_signal((vq)->error_ctx, 1);\
	} while (0)

enum {
	VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
			 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
			 (1ULL << VIRTIO_RING_F_EVENT_IDX) |
			 (1ULL << VHOST_F_LOG_ALL) |
			 (1ULL << VIRTIO_F_ANY_LAYOUT) |
			 (1ULL << VIRTIO_F_VERSION_1)
};

/**
 * vhost_vq_set_backend - Set backend.
 *
 * @vq            Virtqueue.
 * @private_data  The private data.
 *
 * Context: Need to call with vq->mutex acquired.
 */
static inline void vhost_vq_set_backend(struct vhost_virtqueue *vq,
					void *private_data)
{
	vq->private_data = private_data;
}

/**
 * vhost_vq_get_backend - Get backend.
 *
 * @vq            Virtqueue.
 *
 * Context: Need to call with vq->mutex acquired.
 * Return: Private data previously set with vhost_vq_set_backend.
 */
static inline void *vhost_vq_get_backend(struct vhost_virtqueue *vq)
{
	return vq->private_data;
}

static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
{
	return vq->acked_features & (1ULL << bit);
}

static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
{
	return vq->acked_backend_features & (1ULL << bit);
}

#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
{
	return vq->is_le;
}
#else
static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
{
	return virtio_legacy_is_little_endian() || vq->is_le;
}
#endif

/* Memory accessors */
static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
{
	return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
}

static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
{
	return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
}

static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
{
	return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
}

static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
{
	return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
}

static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
{
	return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
}

static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
{
	return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
}
#endif