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 #include <linux/unroll.h> 18 19 struct vhost_work; 20 struct vhost_task; 21 typedef void (*vhost_work_fn_t)(struct vhost_work *work); 22 23 #define VHOST_WORK_QUEUED 1 24 struct vhost_work { 25 struct llist_node node; 26 vhost_work_fn_t fn; 27 unsigned long flags; 28 }; 29 30 struct vhost_worker; 31 struct vhost_dev; 32 struct vhost_msg_node; 33 34 struct vhost_worker_ops { 35 int (*create)(struct vhost_worker *worker, struct vhost_dev *dev, 36 const char *name); 37 void (*stop)(struct vhost_worker *worker); 38 void (*wakeup)(struct vhost_worker *worker); 39 }; 40 41 struct vhost_worker { 42 struct task_struct *kthread_task; 43 struct vhost_task *vtsk; 44 struct vhost_dev *dev; 45 /* Used to serialize device wide flushing with worker swapping. */ 46 struct mutex mutex; 47 struct llist_head work_list; 48 struct kcov_common_handle_id kcov_handle; 49 u32 id; 50 int attachment_cnt; 51 bool killed; 52 const struct vhost_worker_ops *ops; 53 }; 54 55 /* Poll a file (eventfd or socket) */ 56 /* Note: there's nothing vhost specific about this structure. */ 57 struct vhost_poll { 58 poll_table table; 59 wait_queue_head_t *wqh; 60 wait_queue_entry_t wait; 61 struct vhost_work work; 62 __poll_t mask; 63 struct vhost_dev *dev; 64 struct vhost_virtqueue *vq; 65 }; 66 67 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, 68 __poll_t mask, struct vhost_dev *dev, 69 struct vhost_virtqueue *vq); 70 int vhost_poll_start(struct vhost_poll *poll, struct file *file); 71 void vhost_poll_stop(struct vhost_poll *poll); 72 void vhost_poll_queue(struct vhost_poll *poll); 73 74 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn); 75 void vhost_dev_flush(struct vhost_dev *dev); 76 77 struct vhost_log { 78 u64 addr; 79 u64 len; 80 }; 81 82 enum vhost_uaddr_type { 83 VHOST_ADDR_DESC = 0, 84 VHOST_ADDR_AVAIL = 1, 85 VHOST_ADDR_USED = 2, 86 VHOST_NUM_ADDRS = 3, 87 }; 88 89 struct vhost_vring_call { 90 struct eventfd_ctx *ctx; 91 struct irq_bypass_producer producer; 92 }; 93 94 /* The virtqueue structure describes a queue attached to a device. */ 95 struct vhost_virtqueue { 96 struct vhost_dev *dev; 97 struct vhost_worker __rcu *worker; 98 99 /* The actual ring of buffers. */ 100 struct mutex mutex; 101 unsigned int num; 102 vring_desc_t __user *desc; 103 vring_avail_t __user *avail; 104 vring_used_t __user *used; 105 const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS]; 106 struct file *kick; 107 struct vhost_vring_call call_ctx; 108 struct eventfd_ctx *error_ctx; 109 struct eventfd_ctx *log_ctx; 110 111 struct vhost_poll poll; 112 113 /* The routine to call when the Guest pings us, or timeout. */ 114 vhost_work_fn_t handle_kick; 115 116 /* Last available index we saw. 117 * Values are limited to 0x7fff, and the high bit is used as 118 * a wrap counter when using VIRTIO_F_RING_PACKED. */ 119 u16 last_avail_idx; 120 /* Next avail ring head when VIRTIO_F_IN_ORDER is negoitated */ 121 u16 next_avail_head; 122 123 /* Caches available index value from user. */ 124 u16 avail_idx; 125 126 /* Last index we used. 127 * Values are limited to 0x7fff, and the high bit is used as 128 * a wrap counter when using VIRTIO_F_RING_PACKED. */ 129 u16 last_used_idx; 130 131 /* Used flags */ 132 u16 used_flags; 133 134 /* Last used index value we have signalled on */ 135 u16 signalled_used; 136 137 /* Last used index value we have signalled on */ 138 bool signalled_used_valid; 139 140 /* Log writes to used structure. */ 141 bool log_used; 142 u64 log_addr; 143 144 struct iovec iov[UIO_MAXIOV]; 145 struct iovec iotlb_iov[64]; 146 struct iovec *indirect; 147 struct vring_used_elem *heads; 148 u16 *nheads; 149 /* Protected by virtqueue mutex. */ 150 struct vhost_iotlb *umem; 151 struct vhost_iotlb *iotlb; 152 /* Protected by dev->iotlb_lock. */ 153 struct vhost_msg_node *iotlb_miss; 154 void *private_data; 155 VIRTIO_DECLARE_FEATURES(acked_features); 156 u64 acked_backend_features; 157 /* Log write descriptors */ 158 void __user *log_base; 159 struct vhost_log *log; 160 struct iovec log_iov[64]; 161 162 /* Ring endianness. Defaults to legacy native endianness. 163 * Set to true when starting a modern virtio device. */ 164 bool is_le; 165 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY 166 /* Ring endianness requested by userspace for cross-endian support. */ 167 bool user_be; 168 #endif 169 u32 busyloop_timeout; 170 }; 171 172 struct vhost_msg_node { 173 union { 174 struct vhost_msg msg; 175 struct vhost_msg_v2 msg_v2; 176 }; 177 struct vhost_virtqueue *vq; 178 struct list_head node; 179 }; 180 181 struct vhost_dev { 182 struct mm_struct *mm; 183 struct mutex mutex; 184 struct vhost_virtqueue **vqs; 185 int nvqs; 186 struct eventfd_ctx *log_ctx; 187 struct vhost_iotlb *umem; 188 struct vhost_iotlb *iotlb; 189 spinlock_t iotlb_lock; 190 struct list_head read_list; 191 struct list_head pending_list; 192 wait_queue_head_t wait; 193 int iov_limit; 194 int weight; 195 int byte_weight; 196 struct xarray worker_xa; 197 bool use_worker; 198 /* 199 * If fork_owner is true we use vhost_tasks to create 200 * the worker so all settings/limits like cgroups, NPROC, 201 * scheduler, etc are inherited from the owner. If false, 202 * we use kthreads and only attach to the same cgroups 203 * as the owner for compat with older kernels. 204 * here we use true as default value. 205 * The default value is set by fork_from_owner_default 206 */ 207 bool fork_owner; 208 int (*msg_handler)(struct vhost_dev *dev, u32 asid, 209 struct vhost_iotlb_msg *msg); 210 }; 211 212 bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len); 213 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, 214 int nvqs, int iov_limit, int weight, int byte_weight, 215 bool use_worker, 216 int (*msg_handler)(struct vhost_dev *dev, u32 asid, 217 struct vhost_iotlb_msg *msg)); 218 long vhost_dev_set_owner(struct vhost_dev *dev); 219 bool vhost_dev_has_owner(struct vhost_dev *dev); 220 long vhost_dev_check_owner(struct vhost_dev *); 221 struct vhost_iotlb *vhost_dev_reset_owner_prepare(void); 222 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *iotlb); 223 void vhost_dev_cleanup(struct vhost_dev *); 224 void vhost_dev_stop(struct vhost_dev *); 225 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp); 226 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp); 227 long vhost_worker_ioctl(struct vhost_dev *dev, unsigned int ioctl, 228 void __user *argp); 229 bool vhost_vq_access_ok(struct vhost_virtqueue *vq); 230 bool vhost_log_access_ok(struct vhost_dev *); 231 void vhost_clear_msg(struct vhost_dev *dev); 232 233 int vhost_get_vq_desc(struct vhost_virtqueue *, 234 struct iovec iov[], unsigned int iov_size, 235 unsigned int *out_num, unsigned int *in_num, 236 struct vhost_log *log, unsigned int *log_num); 237 238 int vhost_get_vq_desc_n(struct vhost_virtqueue *vq, 239 struct iovec iov[], unsigned int iov_size, 240 unsigned int *out_num, unsigned int *in_num, 241 struct vhost_log *log, unsigned int *log_num, 242 unsigned int *ndesc); 243 244 void vhost_discard_vq_desc(struct vhost_virtqueue *, int nbuf, 245 unsigned int ndesc); 246 247 bool vhost_vq_work_queue(struct vhost_virtqueue *vq, struct vhost_work *work); 248 bool vhost_vq_has_work(struct vhost_virtqueue *vq); 249 bool vhost_vq_is_setup(struct vhost_virtqueue *vq); 250 int vhost_vq_init_access(struct vhost_virtqueue *); 251 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len); 252 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads, 253 u16 *nheads, unsigned count); 254 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *, 255 unsigned int id, int len); 256 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, 257 struct vring_used_elem *heads, u16 *nheads, 258 unsigned count); 259 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); 260 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *); 261 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *); 262 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *); 263 264 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, 265 unsigned int log_num, u64 len, 266 struct iovec *iov, int count); 267 int vq_meta_prefetch(struct vhost_virtqueue *vq); 268 269 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type); 270 void vhost_enqueue_msg(struct vhost_dev *dev, 271 struct list_head *head, 272 struct vhost_msg_node *node); 273 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev, 274 struct list_head *head); 275 void vhost_set_backend_features(struct vhost_dev *dev, u64 features); 276 277 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev, 278 poll_table *wait); 279 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to, 280 int noblock); 281 ssize_t vhost_chr_write_iter(struct vhost_dev *dev, 282 struct iov_iter *from); 283 void vhost_clear_device_iotlb(struct vhost_dev *d); 284 int vhost_init_device_iotlb(struct vhost_dev *d); 285 286 void vhost_iotlb_map_free(struct vhost_iotlb *iotlb, 287 struct vhost_iotlb_map *map); 288 289 #define vq_err(vq, fmt, ...) do { \ 290 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \ 291 if ((vq)->error_ctx) \ 292 eventfd_signal((vq)->error_ctx);\ 293 } while (0) 294 295 #define VHOST_FEATURES \ 296 VIRTIO_F_NOTIFY_ON_EMPTY, \ 297 VIRTIO_RING_F_INDIRECT_DESC, \ 298 VIRTIO_RING_F_EVENT_IDX, \ 299 VHOST_F_LOG_ALL, \ 300 VIRTIO_F_ANY_LAYOUT, \ 301 VIRTIO_F_VERSION_1 302 303 static inline u64 vhost_features_u64(const int *features, int size, int idx) 304 { 305 u64 res = 0; 306 307 unrolled_count(VIRTIO_FEATURES_BITS) 308 for (int i = 0; i < size; ++i) { 309 int bit = features[i]; 310 311 if (virtio_features_chk_bit(bit) && VIRTIO_U64(bit) == idx) 312 res |= VIRTIO_BIT(bit); 313 } 314 return res; 315 } 316 317 #define VHOST_FEATURES_U64(features, idx) \ 318 vhost_features_u64(features, ARRAY_SIZE(features), idx) 319 320 #define DEFINE_VHOST_FEATURES_ARRAY_ENTRY(idx, features) \ 321 [idx] = VHOST_FEATURES_U64(features, idx), 322 323 #define DEFINE_VHOST_FEATURES_ARRAY(array, features) \ 324 u64 array[VIRTIO_FEATURES_U64S] = { \ 325 UNROLL(VIRTIO_FEATURES_U64S, \ 326 DEFINE_VHOST_FEATURES_ARRAY_ENTRY, features) \ 327 } 328 329 /** 330 * vhost_vq_set_backend - Set backend. 331 * 332 * @vq Virtqueue. 333 * @private_data The private data. 334 * 335 * Context: Need to call with vq->mutex acquired. 336 */ 337 static inline void vhost_vq_set_backend(struct vhost_virtqueue *vq, 338 void *private_data) 339 { 340 vq->private_data = private_data; 341 } 342 343 /** 344 * vhost_vq_get_backend - Get backend. 345 * 346 * @vq Virtqueue. 347 * 348 * Context: Need to call with vq->mutex acquired. 349 * Return: Private data previously set with vhost_vq_set_backend. 350 */ 351 static inline void *vhost_vq_get_backend(struct vhost_virtqueue *vq) 352 { 353 return vq->private_data; 354 } 355 356 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit) 357 { 358 return virtio_features_test_bit(vq->acked_features_array, bit); 359 } 360 361 static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit) 362 { 363 return vq->acked_backend_features & (1ULL << bit); 364 } 365 366 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY 367 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq) 368 { 369 return vq->is_le; 370 } 371 #else 372 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq) 373 { 374 return virtio_legacy_is_little_endian() || vq->is_le; 375 } 376 #endif 377 378 /* Memory accessors */ 379 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val) 380 { 381 return __virtio16_to_cpu(vhost_is_little_endian(vq), val); 382 } 383 384 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val) 385 { 386 return __cpu_to_virtio16(vhost_is_little_endian(vq), val); 387 } 388 389 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val) 390 { 391 return __virtio32_to_cpu(vhost_is_little_endian(vq), val); 392 } 393 394 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val) 395 { 396 return __cpu_to_virtio32(vhost_is_little_endian(vq), val); 397 } 398 399 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val) 400 { 401 return __virtio64_to_cpu(vhost_is_little_endian(vq), val); 402 } 403 404 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val) 405 { 406 return __cpu_to_virtio64(vhost_is_little_endian(vq), val); 407 } 408 #endif 409