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_flush(struct vhost_poll *poll);
48 void vhost_poll_queue(struct vhost_poll *poll);
49 void vhost_work_dev_flush(struct vhost_dev *dev);
50
51 struct vhost_log {
52 u64 addr;
53 u64 len;
54 };
55
56 enum vhost_uaddr_type {
57 VHOST_ADDR_DESC = 0,
58 VHOST_ADDR_AVAIL = 1,
59 VHOST_ADDR_USED = 2,
60 VHOST_NUM_ADDRS = 3,
61 };
62
63 struct vhost_vring_call {
64 struct eventfd_ctx *ctx;
65 struct irq_bypass_producer producer;
66 };
67
68 /* The virtqueue structure describes a queue attached to a device. */
69 struct vhost_virtqueue {
70 struct vhost_dev *dev;
71
72 /* The actual ring of buffers. */
73 struct mutex mutex;
74 unsigned int num;
75 vring_desc_t __user *desc;
76 vring_avail_t __user *avail;
77 vring_used_t __user *used;
78 const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
79 struct file *kick;
80 struct vhost_vring_call call_ctx;
81 struct eventfd_ctx *error_ctx;
82 struct eventfd_ctx *log_ctx;
83
84 struct vhost_poll poll;
85
86 /* The routine to call when the Guest pings us, or timeout. */
87 vhost_work_fn_t handle_kick;
88
89 /* Last available index we saw. */
90 u16 last_avail_idx;
91
92 /* Caches available index value from user. */
93 u16 avail_idx;
94
95 /* Last index we used. */
96 u16 last_used_idx;
97
98 /* Used flags */
99 u16 used_flags;
100
101 /* Last used index value we have signalled on */
102 u16 signalled_used;
103
104 /* Last used index value we have signalled on */
105 bool signalled_used_valid;
106
107 /* Log writes to used structure. */
108 bool log_used;
109 u64 log_addr;
110
111 struct iovec iov[UIO_MAXIOV];
112 struct iovec iotlb_iov[64];
113 struct iovec *indirect;
114 struct vring_used_elem *heads;
115 /* Protected by virtqueue mutex. */
116 struct vhost_iotlb *umem;
117 struct vhost_iotlb *iotlb;
118 void *private_data;
119 u64 acked_features;
120 u64 acked_backend_features;
121 /* Log write descriptors */
122 void __user *log_base;
123 struct vhost_log *log;
124 struct iovec log_iov[64];
125
126 /* Ring endianness. Defaults to legacy native endianness.
127 * Set to true when starting a modern virtio device. */
128 bool is_le;
129 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
130 /* Ring endianness requested by userspace for cross-endian support. */
131 bool user_be;
132 #endif
133 u32 busyloop_timeout;
134 };
135
136 struct vhost_msg_node {
137 union {
138 struct vhost_msg msg;
139 struct vhost_msg_v2 msg_v2;
140 };
141 struct vhost_virtqueue *vq;
142 struct list_head node;
143 };
144
145 struct vhost_dev {
146 struct mm_struct *mm;
147 struct mutex mutex;
148 struct vhost_virtqueue **vqs;
149 int nvqs;
150 struct eventfd_ctx *log_ctx;
151 struct llist_head work_list;
152 struct task_struct *worker;
153 struct vhost_iotlb *umem;
154 struct vhost_iotlb *iotlb;
155 spinlock_t iotlb_lock;
156 struct list_head read_list;
157 struct list_head pending_list;
158 wait_queue_head_t wait;
159 int iov_limit;
160 int weight;
161 int byte_weight;
162 u64 kcov_handle;
163 bool use_worker;
164 int (*msg_handler)(struct vhost_dev *dev,
165 struct vhost_iotlb_msg *msg);
166 };
167
168 bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
169 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
170 int nvqs, int iov_limit, int weight, int byte_weight,
171 bool use_worker,
172 int (*msg_handler)(struct vhost_dev *dev,
173 struct vhost_iotlb_msg *msg));
174 long vhost_dev_set_owner(struct vhost_dev *dev);
175 bool vhost_dev_has_owner(struct vhost_dev *dev);
176 long vhost_dev_check_owner(struct vhost_dev *);
177 struct vhost_iotlb *vhost_dev_reset_owner_prepare(void);
178 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *iotlb);
179 void vhost_dev_cleanup(struct vhost_dev *);
180 void vhost_dev_stop(struct vhost_dev *);
181 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
182 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
183 bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
184 bool vhost_log_access_ok(struct vhost_dev *);
185
186 int vhost_get_vq_desc(struct vhost_virtqueue *,
187 struct iovec iov[], unsigned int iov_count,
188 unsigned int *out_num, unsigned int *in_num,
189 struct vhost_log *log, unsigned int *log_num);
190 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
191
192 bool vhost_vq_is_setup(struct vhost_virtqueue *vq);
193 int vhost_vq_init_access(struct vhost_virtqueue *);
194 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
195 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
196 unsigned count);
197 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
198 unsigned int id, int len);
199 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
200 struct vring_used_elem *heads, unsigned count);
201 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
202 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
203 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
204 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
205
206 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
207 unsigned int log_num, u64 len,
208 struct iovec *iov, int count);
209 int vq_meta_prefetch(struct vhost_virtqueue *vq);
210
211 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
212 void vhost_enqueue_msg(struct vhost_dev *dev,
213 struct list_head *head,
214 struct vhost_msg_node *node);
215 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
216 struct list_head *head);
217 void vhost_set_backend_features(struct vhost_dev *dev, u64 features);
218
219 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
220 poll_table *wait);
221 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
222 int noblock);
223 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
224 struct iov_iter *from);
225 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
226
227 void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
228 struct vhost_iotlb_map *map);
229
230 #define vq_err(vq, fmt, ...) do { \
231 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
232 if ((vq)->error_ctx) \
233 eventfd_signal((vq)->error_ctx, 1);\
234 } while (0)
235
236 enum {
237 VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
238 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
239 (1ULL << VIRTIO_RING_F_EVENT_IDX) |
240 (1ULL << VHOST_F_LOG_ALL) |
241 (1ULL << VIRTIO_F_ANY_LAYOUT) |
242 (1ULL << VIRTIO_F_VERSION_1)
243 };
244
245 /**
246 * vhost_vq_set_backend - Set backend.
247 *
248 * @vq Virtqueue.
249 * @private_data The private data.
250 *
251 * Context: Need to call with vq->mutex acquired.
252 */
vhost_vq_set_backend(struct vhost_virtqueue * vq,void * private_data)253 static inline void vhost_vq_set_backend(struct vhost_virtqueue *vq,
254 void *private_data)
255 {
256 vq->private_data = private_data;
257 }
258
259 /**
260 * vhost_vq_get_backend - Get backend.
261 *
262 * @vq Virtqueue.
263 *
264 * Context: Need to call with vq->mutex acquired.
265 * Return: Private data previously set with vhost_vq_set_backend.
266 */
vhost_vq_get_backend(struct vhost_virtqueue * vq)267 static inline void *vhost_vq_get_backend(struct vhost_virtqueue *vq)
268 {
269 return vq->private_data;
270 }
271
vhost_has_feature(struct vhost_virtqueue * vq,int bit)272 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
273 {
274 return vq->acked_features & (1ULL << bit);
275 }
276
vhost_backend_has_feature(struct vhost_virtqueue * vq,int bit)277 static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
278 {
279 return vq->acked_backend_features & (1ULL << bit);
280 }
281
282 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
vhost_is_little_endian(struct vhost_virtqueue * vq)283 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
284 {
285 return vq->is_le;
286 }
287 #else
vhost_is_little_endian(struct vhost_virtqueue * vq)288 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
289 {
290 return virtio_legacy_is_little_endian() || vq->is_le;
291 }
292 #endif
293
294 /* Memory accessors */
vhost16_to_cpu(struct vhost_virtqueue * vq,__virtio16 val)295 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
296 {
297 return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
298 }
299
cpu_to_vhost16(struct vhost_virtqueue * vq,u16 val)300 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
301 {
302 return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
303 }
304
vhost32_to_cpu(struct vhost_virtqueue * vq,__virtio32 val)305 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
306 {
307 return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
308 }
309
cpu_to_vhost32(struct vhost_virtqueue * vq,u32 val)310 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
311 {
312 return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
313 }
314
vhost64_to_cpu(struct vhost_virtqueue * vq,__virtio64 val)315 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
316 {
317 return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
318 }
319
cpu_to_vhost64(struct vhost_virtqueue * vq,u64 val)320 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
321 {
322 return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
323 }
324 #endif
325
