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