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