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