1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _VHOST_H
3 #define _VHOST_H
4
5 #include <linux/eventfd.h>
6 #include <linux/vhost.h>
7 #include <linux/mm.h>
8 #include <linux/mutex.h>
9 #include <linux/poll.h>
10 #include <linux/file.h>
11 #include <linux/uio.h>
12 #include <linux/virtio_config.h>
13 #include <linux/virtio_ring.h>
14 #include <linux/atomic.h>
15 #include <linux/vhost_iotlb.h>
16 #include <linux/irqbypass.h>
17
18 struct vhost_work;
19 struct vhost_task;
20 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
21
22 #define VHOST_WORK_QUEUED 1
23 struct vhost_work {
24 struct llist_node node;
25 vhost_work_fn_t fn;
26 unsigned long flags;
27 };
28
29 struct vhost_worker {
30 struct vhost_task *vtsk;
31 struct vhost_dev *dev;
32 /* Used to serialize device wide flushing with worker swapping. */
33 struct mutex mutex;
34 struct llist_head work_list;
35 u64 kcov_handle;
36 u32 id;
37 int attachment_cnt;
38 bool killed;
39 };
40
41 /* Poll a file (eventfd or socket) */
42 /* Note: there's nothing vhost specific about this structure. */
43 struct vhost_poll {
44 poll_table table;
45 wait_queue_head_t *wqh;
46 wait_queue_entry_t wait;
47 struct vhost_work work;
48 __poll_t mask;
49 struct vhost_dev *dev;
50 struct vhost_virtqueue *vq;
51 };
52
53 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
54 __poll_t mask, struct vhost_dev *dev,
55 struct vhost_virtqueue *vq);
56 int vhost_poll_start(struct vhost_poll *poll, struct file *file);
57 void vhost_poll_stop(struct vhost_poll *poll);
58 void vhost_poll_queue(struct vhost_poll *poll);
59
60 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
61 void vhost_dev_flush(struct vhost_dev *dev);
62
63 struct vhost_log {
64 u64 addr;
65 u64 len;
66 };
67
68 enum vhost_uaddr_type {
69 VHOST_ADDR_DESC = 0,
70 VHOST_ADDR_AVAIL = 1,
71 VHOST_ADDR_USED = 2,
72 VHOST_NUM_ADDRS = 3,
73 };
74
75 struct vhost_vring_call {
76 struct eventfd_ctx *ctx;
77 struct irq_bypass_producer producer;
78 };
79
80 /* The virtqueue structure describes a queue attached to a device. */
81 struct vhost_virtqueue {
82 struct vhost_dev *dev;
83 struct vhost_worker __rcu *worker;
84
85 /* The actual ring of buffers. */
86 struct mutex mutex;
87 unsigned int num;
88 vring_desc_t __user *desc;
89 vring_avail_t __user *avail;
90 vring_used_t __user *used;
91 const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
92 struct file *kick;
93 struct vhost_vring_call call_ctx;
94 struct eventfd_ctx *error_ctx;
95 struct eventfd_ctx *log_ctx;
96
97 struct vhost_poll poll;
98
99 /* The routine to call when the Guest pings us, or timeout. */
100 vhost_work_fn_t handle_kick;
101
102 /* Last available index we saw.
103 * Values are limited to 0x7fff, and the high bit is used as
104 * a wrap counter when using VIRTIO_F_RING_PACKED. */
105 u16 last_avail_idx;
106
107 /* Caches available index value from user. */
108 u16 avail_idx;
109
110 /* Last index we used.
111 * Values are limited to 0x7fff, and the high bit is used as
112 * a wrap counter when using VIRTIO_F_RING_PACKED. */
113 u16 last_used_idx;
114
115 /* Used flags */
116 u16 used_flags;
117
118 /* Last used index value we have signalled on */
119 u16 signalled_used;
120
121 /* Last used index value we have signalled on */
122 bool signalled_used_valid;
123
124 /* Log writes to used structure. */
125 bool log_used;
126 u64 log_addr;
127
128 struct iovec iov[UIO_MAXIOV];
129 struct iovec iotlb_iov[64];
130 struct iovec *indirect;
131 struct vring_used_elem *heads;
132 /* Protected by virtqueue mutex. */
133 struct vhost_iotlb *umem;
134 struct vhost_iotlb *iotlb;
135 void *private_data;
136 u64 acked_features;
137 u64 acked_backend_features;
138 /* Log write descriptors */
139 void __user *log_base;
140 struct vhost_log *log;
141 struct iovec log_iov[64];
142
143 /* Ring endianness. Defaults to legacy native endianness.
144 * Set to true when starting a modern virtio device. */
145 bool is_le;
146 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
147 /* Ring endianness requested by userspace for cross-endian support. */
148 bool user_be;
149 #endif
150 u32 busyloop_timeout;
151 };
152
153 struct vhost_msg_node {
154 union {
155 struct vhost_msg msg;
156 struct vhost_msg_v2 msg_v2;
157 };
158 struct vhost_virtqueue *vq;
159 struct list_head node;
160 };
161
162 struct vhost_dev {
163 struct mm_struct *mm;
164 struct mutex mutex;
165 struct vhost_virtqueue **vqs;
166 int nvqs;
167 struct eventfd_ctx *log_ctx;
168 struct vhost_iotlb *umem;
169 struct vhost_iotlb *iotlb;
170 spinlock_t iotlb_lock;
171 struct list_head read_list;
172 struct list_head pending_list;
173 wait_queue_head_t wait;
174 int iov_limit;
175 int weight;
176 int byte_weight;
177 struct xarray worker_xa;
178 bool use_worker;
179 int (*msg_handler)(struct vhost_dev *dev, u32 asid,
180 struct vhost_iotlb_msg *msg);
181 };
182
183 bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
184 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
185 int nvqs, int iov_limit, int weight, int byte_weight,
186 bool use_worker,
187 int (*msg_handler)(struct vhost_dev *dev, u32 asid,
188 struct vhost_iotlb_msg *msg));
189 long vhost_dev_set_owner(struct vhost_dev *dev);
190 bool vhost_dev_has_owner(struct vhost_dev *dev);
191 long vhost_dev_check_owner(struct vhost_dev *);
192 struct vhost_iotlb *vhost_dev_reset_owner_prepare(void);
193 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *iotlb);
194 void vhost_dev_cleanup(struct vhost_dev *);
195 void vhost_dev_stop(struct vhost_dev *);
196 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
197 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
198 long vhost_worker_ioctl(struct vhost_dev *dev, unsigned int ioctl,
199 void __user *argp);
200 bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
201 bool vhost_log_access_ok(struct vhost_dev *);
202 void vhost_clear_msg(struct vhost_dev *dev);
203
204 int vhost_get_vq_desc(struct vhost_virtqueue *,
205 struct iovec iov[], unsigned int iov_size,
206 unsigned int *out_num, unsigned int *in_num,
207 struct vhost_log *log, unsigned int *log_num);
208 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
209
210 bool vhost_vq_work_queue(struct vhost_virtqueue *vq, struct vhost_work *work);
211 bool vhost_vq_has_work(struct vhost_virtqueue *vq);
212 bool vhost_vq_is_setup(struct vhost_virtqueue *vq);
213 int vhost_vq_init_access(struct vhost_virtqueue *);
214 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
215 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
216 unsigned count);
217 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
218 unsigned int id, int len);
219 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
220 struct vring_used_elem *heads, unsigned count);
221 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
222 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
223 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
224 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
225
226 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
227 unsigned int log_num, u64 len,
228 struct iovec *iov, int count);
229 int vq_meta_prefetch(struct vhost_virtqueue *vq);
230
231 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
232 void vhost_enqueue_msg(struct vhost_dev *dev,
233 struct list_head *head,
234 struct vhost_msg_node *node);
235 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
236 struct list_head *head);
237 void vhost_set_backend_features(struct vhost_dev *dev, u64 features);
238
239 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
240 poll_table *wait);
241 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
242 int noblock);
243 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
244 struct iov_iter *from);
245 int vhost_init_device_iotlb(struct vhost_dev *d);
246
247 void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
248 struct vhost_iotlb_map *map);
249
250 #define vq_err(vq, fmt, ...) do { \
251 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
252 if ((vq)->error_ctx) \
253 eventfd_signal((vq)->error_ctx);\
254 } while (0)
255
256 enum {
257 VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
258 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
259 (1ULL << VIRTIO_RING_F_EVENT_IDX) |
260 (1ULL << VHOST_F_LOG_ALL) |
261 (1ULL << VIRTIO_F_ANY_LAYOUT) |
262 (1ULL << VIRTIO_F_VERSION_1)
263 };
264
265 /**
266 * vhost_vq_set_backend - Set backend.
267 *
268 * @vq Virtqueue.
269 * @private_data The private data.
270 *
271 * Context: Need to call with vq->mutex acquired.
272 */
vhost_vq_set_backend(struct vhost_virtqueue * vq,void * private_data)273 static inline void vhost_vq_set_backend(struct vhost_virtqueue *vq,
274 void *private_data)
275 {
276 vq->private_data = private_data;
277 }
278
279 /**
280 * vhost_vq_get_backend - Get backend.
281 *
282 * @vq Virtqueue.
283 *
284 * Context: Need to call with vq->mutex acquired.
285 * Return: Private data previously set with vhost_vq_set_backend.
286 */
vhost_vq_get_backend(struct vhost_virtqueue * vq)287 static inline void *vhost_vq_get_backend(struct vhost_virtqueue *vq)
288 {
289 return vq->private_data;
290 }
291
vhost_has_feature(struct vhost_virtqueue * vq,int bit)292 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
293 {
294 return vq->acked_features & (1ULL << bit);
295 }
296
vhost_backend_has_feature(struct vhost_virtqueue * vq,int bit)297 static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
298 {
299 return vq->acked_backend_features & (1ULL << bit);
300 }
301
302 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
vhost_is_little_endian(struct vhost_virtqueue * vq)303 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
304 {
305 return vq->is_le;
306 }
307 #else
vhost_is_little_endian(struct vhost_virtqueue * vq)308 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
309 {
310 return virtio_legacy_is_little_endian() || vq->is_le;
311 }
312 #endif
313
314 /* Memory accessors */
vhost16_to_cpu(struct vhost_virtqueue * vq,__virtio16 val)315 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
316 {
317 return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
318 }
319
cpu_to_vhost16(struct vhost_virtqueue * vq,u16 val)320 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
321 {
322 return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
323 }
324
vhost32_to_cpu(struct vhost_virtqueue * vq,__virtio32 val)325 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
326 {
327 return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
328 }
329
cpu_to_vhost32(struct vhost_virtqueue * vq,u32 val)330 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
331 {
332 return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
333 }
334
vhost64_to_cpu(struct vhost_virtqueue * vq,__virtio64 val)335 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
336 {
337 return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
338 }
339
cpu_to_vhost64(struct vhost_virtqueue * vq,u64 val)340 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
341 {
342 return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
343 }
344 #endif
345