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