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/pagemap.h> 16 #include <linux/mmu_notifier.h> 17 #include <asm/cacheflush.h> 18 19 struct vhost_work; 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 /* Poll a file (eventfd or socket) */ 30 /* Note: there's nothing vhost specific about this structure. */ 31 struct vhost_poll { 32 poll_table table; 33 wait_queue_head_t *wqh; 34 wait_queue_entry_t wait; 35 struct vhost_work work; 36 __poll_t mask; 37 struct vhost_dev *dev; 38 }; 39 40 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn); 41 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work); 42 bool vhost_has_work(struct vhost_dev *dev); 43 44 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, 45 __poll_t mask, struct vhost_dev *dev); 46 int vhost_poll_start(struct vhost_poll *poll, struct file *file); 47 void vhost_poll_stop(struct vhost_poll *poll); 48 void vhost_poll_flush(struct vhost_poll *poll); 49 void vhost_poll_queue(struct vhost_poll *poll); 50 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work); 51 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp); 52 53 struct vhost_log { 54 u64 addr; 55 u64 len; 56 }; 57 58 #define START(node) ((node)->start) 59 #define LAST(node) ((node)->last) 60 61 struct vhost_umem_node { 62 struct rb_node rb; 63 struct list_head link; 64 __u64 start; 65 __u64 last; 66 __u64 size; 67 __u64 userspace_addr; 68 __u32 perm; 69 __u32 flags_padding; 70 __u64 __subtree_last; 71 }; 72 73 struct vhost_umem { 74 struct rb_root_cached umem_tree; 75 struct list_head umem_list; 76 int numem; 77 }; 78 79 enum vhost_uaddr_type { 80 VHOST_ADDR_DESC = 0, 81 VHOST_ADDR_AVAIL = 1, 82 VHOST_ADDR_USED = 2, 83 VHOST_NUM_ADDRS = 3, 84 }; 85 86 struct vhost_map { 87 int npages; 88 void *addr; 89 struct page **pages; 90 }; 91 92 struct vhost_uaddr { 93 unsigned long uaddr; 94 size_t size; 95 bool write; 96 }; 97 98 #if defined(CONFIG_MMU_NOTIFIER) && ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 0 99 #define VHOST_ARCH_CAN_ACCEL_UACCESS 1 100 #else 101 #define VHOST_ARCH_CAN_ACCEL_UACCESS 0 102 #endif 103 104 /* The virtqueue structure describes a queue attached to a device. */ 105 struct vhost_virtqueue { 106 struct vhost_dev *dev; 107 108 /* The actual ring of buffers. */ 109 struct mutex mutex; 110 unsigned int num; 111 struct vring_desc __user *desc; 112 struct vring_avail __user *avail; 113 struct vring_used __user *used; 114 115 #if VHOST_ARCH_CAN_ACCEL_UACCESS 116 /* Read by memory accessors, modified by meta data 117 * prefetching, MMU notifier and vring ioctl(). 118 * Synchonrized through mmu_lock (writers) and RCU (writers 119 * and readers). 120 */ 121 struct vhost_map __rcu *maps[VHOST_NUM_ADDRS]; 122 /* Read by MMU notifier, modified by vring ioctl(), 123 * synchronized through MMU notifier 124 * registering/unregistering. 125 */ 126 struct vhost_uaddr uaddrs[VHOST_NUM_ADDRS]; 127 #endif 128 const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS]; 129 130 struct file *kick; 131 struct eventfd_ctx *call_ctx; 132 struct eventfd_ctx *error_ctx; 133 struct eventfd_ctx *log_ctx; 134 135 struct vhost_poll poll; 136 137 /* The routine to call when the Guest pings us, or timeout. */ 138 vhost_work_fn_t handle_kick; 139 140 /* Last available index we saw. */ 141 u16 last_avail_idx; 142 143 /* Caches available index value from user. */ 144 u16 avail_idx; 145 146 /* Last index we used. */ 147 u16 last_used_idx; 148 149 /* Used flags */ 150 u16 used_flags; 151 152 /* Last used index value we have signalled on */ 153 u16 signalled_used; 154 155 /* Last used index value we have signalled on */ 156 bool signalled_used_valid; 157 158 /* Log writes to used structure. */ 159 bool log_used; 160 u64 log_addr; 161 162 struct iovec iov[UIO_MAXIOV]; 163 struct iovec iotlb_iov[64]; 164 struct iovec *indirect; 165 struct vring_used_elem *heads; 166 /* Protected by virtqueue mutex. */ 167 struct vhost_umem *umem; 168 struct vhost_umem *iotlb; 169 void *private_data; 170 u64 acked_features; 171 u64 acked_backend_features; 172 /* Log write descriptors */ 173 void __user *log_base; 174 struct vhost_log *log; 175 176 /* Ring endianness. Defaults to legacy native endianness. 177 * Set to true when starting a modern virtio device. */ 178 bool is_le; 179 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY 180 /* Ring endianness requested by userspace for cross-endian support. */ 181 bool user_be; 182 #endif 183 u32 busyloop_timeout; 184 spinlock_t mmu_lock; 185 int invalidate_count; 186 }; 187 188 struct vhost_msg_node { 189 union { 190 struct vhost_msg msg; 191 struct vhost_msg_v2 msg_v2; 192 }; 193 struct vhost_virtqueue *vq; 194 struct list_head node; 195 }; 196 197 struct vhost_dev { 198 struct mm_struct *mm; 199 #ifdef CONFIG_MMU_NOTIFIER 200 struct mmu_notifier mmu_notifier; 201 #endif 202 struct mutex mutex; 203 struct vhost_virtqueue **vqs; 204 int nvqs; 205 struct eventfd_ctx *log_ctx; 206 struct llist_head work_list; 207 struct task_struct *worker; 208 struct vhost_umem *umem; 209 struct vhost_umem *iotlb; 210 spinlock_t iotlb_lock; 211 struct list_head read_list; 212 struct list_head pending_list; 213 wait_queue_head_t wait; 214 int iov_limit; 215 int weight; 216 int byte_weight; 217 }; 218 219 bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len); 220 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, 221 int nvqs, int iov_limit, int weight, int byte_weight); 222 long vhost_dev_set_owner(struct vhost_dev *dev); 223 bool vhost_dev_has_owner(struct vhost_dev *dev); 224 long vhost_dev_check_owner(struct vhost_dev *); 225 struct vhost_umem *vhost_dev_reset_owner_prepare(void); 226 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_umem *); 227 void vhost_dev_cleanup(struct vhost_dev *); 228 void vhost_dev_stop(struct vhost_dev *); 229 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp); 230 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp); 231 bool vhost_vq_access_ok(struct vhost_virtqueue *vq); 232 bool vhost_log_access_ok(struct vhost_dev *); 233 234 int vhost_get_vq_desc(struct vhost_virtqueue *, 235 struct iovec iov[], unsigned int iov_count, 236 unsigned int *out_num, unsigned int *in_num, 237 struct vhost_log *log, unsigned int *log_num); 238 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n); 239 240 int vhost_vq_init_access(struct vhost_virtqueue *); 241 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len); 242 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads, 243 unsigned count); 244 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *, 245 unsigned int id, int len); 246 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, 247 struct vring_used_elem *heads, unsigned count); 248 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); 249 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *); 250 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *); 251 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *); 252 253 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, 254 unsigned int log_num, u64 len, 255 struct iovec *iov, int count); 256 int vq_meta_prefetch(struct vhost_virtqueue *vq); 257 258 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type); 259 void vhost_enqueue_msg(struct vhost_dev *dev, 260 struct list_head *head, 261 struct vhost_msg_node *node); 262 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev, 263 struct list_head *head); 264 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev, 265 poll_table *wait); 266 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to, 267 int noblock); 268 ssize_t vhost_chr_write_iter(struct vhost_dev *dev, 269 struct iov_iter *from); 270 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled); 271 272 #define vq_err(vq, fmt, ...) do { \ 273 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \ 274 if ((vq)->error_ctx) \ 275 eventfd_signal((vq)->error_ctx, 1);\ 276 } while (0) 277 278 enum { 279 VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | 280 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | 281 (1ULL << VIRTIO_RING_F_EVENT_IDX) | 282 (1ULL << VHOST_F_LOG_ALL) | 283 (1ULL << VIRTIO_F_ANY_LAYOUT) | 284 (1ULL << VIRTIO_F_VERSION_1) 285 }; 286 287 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit) 288 { 289 return vq->acked_features & (1ULL << bit); 290 } 291 292 static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit) 293 { 294 return vq->acked_backend_features & (1ULL << bit); 295 } 296 297 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY 298 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq) 299 { 300 return vq->is_le; 301 } 302 #else 303 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq) 304 { 305 return virtio_legacy_is_little_endian() || vq->is_le; 306 } 307 #endif 308 309 /* Memory accessors */ 310 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val) 311 { 312 return __virtio16_to_cpu(vhost_is_little_endian(vq), val); 313 } 314 315 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val) 316 { 317 return __cpu_to_virtio16(vhost_is_little_endian(vq), val); 318 } 319 320 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val) 321 { 322 return __virtio32_to_cpu(vhost_is_little_endian(vq), val); 323 } 324 325 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val) 326 { 327 return __cpu_to_virtio32(vhost_is_little_endian(vq), val); 328 } 329 330 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val) 331 { 332 return __virtio64_to_cpu(vhost_is_little_endian(vq), val); 333 } 334 335 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val) 336 { 337 return __cpu_to_virtio64(vhost_is_little_endian(vq), val); 338 } 339 #endif 340