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