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 16 struct vhost_work; 17 typedef void (*vhost_work_fn_t)(struct vhost_work *work); 18 19 #define VHOST_WORK_QUEUED 1 20 struct vhost_work { 21 struct llist_node node; 22 vhost_work_fn_t fn; 23 wait_queue_head_t done; 24 int flushing; 25 unsigned queue_seq; 26 unsigned done_seq; 27 unsigned long flags; 28 }; 29 30 /* Poll a file (eventfd or socket) */ 31 /* Note: there's nothing vhost specific about this structure. */ 32 struct vhost_poll { 33 poll_table table; 34 wait_queue_head_t *wqh; 35 wait_queue_entry_t wait; 36 struct vhost_work work; 37 unsigned long mask; 38 struct vhost_dev *dev; 39 }; 40 41 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn); 42 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work); 43 bool vhost_has_work(struct vhost_dev *dev); 44 45 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, 46 unsigned long mask, struct vhost_dev *dev); 47 int vhost_poll_start(struct vhost_poll *poll, struct file *file); 48 void vhost_poll_stop(struct vhost_poll *poll); 49 void vhost_poll_flush(struct vhost_poll *poll); 50 void vhost_poll_queue(struct vhost_poll *poll); 51 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work); 52 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp); 53 54 struct vhost_log { 55 u64 addr; 56 u64 len; 57 }; 58 59 #define START(node) ((node)->start) 60 #define LAST(node) ((node)->last) 61 62 struct vhost_umem_node { 63 struct rb_node rb; 64 struct list_head link; 65 __u64 start; 66 __u64 last; 67 __u64 size; 68 __u64 userspace_addr; 69 __u32 perm; 70 __u32 flags_padding; 71 __u64 __subtree_last; 72 }; 73 74 struct vhost_umem { 75 struct rb_root_cached umem_tree; 76 struct list_head umem_list; 77 int numem; 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 /* The virtqueue structure describes a queue attached to a device. */ 88 struct vhost_virtqueue { 89 struct vhost_dev *dev; 90 91 /* The actual ring of buffers. */ 92 struct mutex mutex; 93 unsigned int num; 94 struct vring_desc __user *desc; 95 struct vring_avail __user *avail; 96 struct vring_used __user *used; 97 const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS]; 98 struct file *kick; 99 struct file *call; 100 struct file *error; 101 struct eventfd_ctx *call_ctx; 102 struct eventfd_ctx *error_ctx; 103 struct eventfd_ctx *log_ctx; 104 105 struct vhost_poll poll; 106 107 /* The routine to call when the Guest pings us, or timeout. */ 108 vhost_work_fn_t handle_kick; 109 110 /* Last available index we saw. */ 111 u16 last_avail_idx; 112 113 /* Caches available index value from user. */ 114 u16 avail_idx; 115 116 /* Last index we used. */ 117 u16 last_used_idx; 118 119 /* Used flags */ 120 u16 used_flags; 121 122 /* Last used index value we have signalled on */ 123 u16 signalled_used; 124 125 /* Last used index value we have signalled on */ 126 bool signalled_used_valid; 127 128 /* Log writes to used structure. */ 129 bool log_used; 130 u64 log_addr; 131 132 struct iovec iov[UIO_MAXIOV]; 133 struct iovec iotlb_iov[64]; 134 struct iovec *indirect; 135 struct vring_used_elem *heads; 136 /* Protected by virtqueue mutex. */ 137 struct vhost_umem *umem; 138 struct vhost_umem *iotlb; 139 void *private_data; 140 u64 acked_features; 141 /* Log write descriptors */ 142 void __user *log_base; 143 struct vhost_log *log; 144 145 /* Ring endianness. Defaults to legacy native endianness. 146 * Set to true when starting a modern virtio device. */ 147 bool is_le; 148 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY 149 /* Ring endianness requested by userspace for cross-endian support. */ 150 bool user_be; 151 #endif 152 u32 busyloop_timeout; 153 }; 154 155 struct vhost_msg_node { 156 struct vhost_msg msg; 157 struct vhost_virtqueue *vq; 158 struct list_head node; 159 }; 160 161 struct vhost_dev { 162 struct mm_struct *mm; 163 struct mutex mutex; 164 struct vhost_virtqueue **vqs; 165 int nvqs; 166 struct file *log_file; 167 struct eventfd_ctx *log_ctx; 168 struct llist_head work_list; 169 struct task_struct *worker; 170 struct vhost_umem *umem; 171 struct vhost_umem *iotlb; 172 spinlock_t iotlb_lock; 173 struct list_head read_list; 174 struct list_head pending_list; 175 wait_queue_head_t wait; 176 }; 177 178 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs); 179 long vhost_dev_set_owner(struct vhost_dev *dev); 180 bool vhost_dev_has_owner(struct vhost_dev *dev); 181 long vhost_dev_check_owner(struct vhost_dev *); 182 struct vhost_umem *vhost_dev_reset_owner_prepare(void); 183 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_umem *); 184 void vhost_dev_cleanup(struct vhost_dev *, bool locked); 185 void vhost_dev_stop(struct vhost_dev *); 186 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp); 187 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp); 188 int vhost_vq_access_ok(struct vhost_virtqueue *vq); 189 int vhost_log_access_ok(struct vhost_dev *); 190 191 int vhost_get_vq_desc(struct vhost_virtqueue *, 192 struct iovec iov[], unsigned int iov_count, 193 unsigned int *out_num, unsigned int *in_num, 194 struct vhost_log *log, unsigned int *log_num); 195 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n); 196 197 int vhost_vq_init_access(struct vhost_virtqueue *); 198 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len); 199 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads, 200 unsigned count); 201 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *, 202 unsigned int id, int len); 203 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, 204 struct vring_used_elem *heads, unsigned count); 205 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); 206 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *); 207 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *); 208 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *); 209 210 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, 211 unsigned int log_num, u64 len); 212 int vq_iotlb_prefetch(struct vhost_virtqueue *vq); 213 214 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type); 215 void vhost_enqueue_msg(struct vhost_dev *dev, 216 struct list_head *head, 217 struct vhost_msg_node *node); 218 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev, 219 struct list_head *head); 220 unsigned int vhost_chr_poll(struct file *file, struct vhost_dev *dev, 221 poll_table *wait); 222 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to, 223 int noblock); 224 ssize_t vhost_chr_write_iter(struct vhost_dev *dev, 225 struct iov_iter *from); 226 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled); 227 228 #define vq_err(vq, fmt, ...) do { \ 229 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \ 230 if ((vq)->error_ctx) \ 231 eventfd_signal((vq)->error_ctx, 1);\ 232 } while (0) 233 234 enum { 235 VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | 236 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | 237 (1ULL << VIRTIO_RING_F_EVENT_IDX) | 238 (1ULL << VHOST_F_LOG_ALL) | 239 (1ULL << VIRTIO_F_ANY_LAYOUT) | 240 (1ULL << VIRTIO_F_VERSION_1) 241 }; 242 243 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit) 244 { 245 return vq->acked_features & (1ULL << bit); 246 } 247 248 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY 249 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq) 250 { 251 return vq->is_le; 252 } 253 #else 254 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq) 255 { 256 return virtio_legacy_is_little_endian() || vq->is_le; 257 } 258 #endif 259 260 /* Memory accessors */ 261 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val) 262 { 263 return __virtio16_to_cpu(vhost_is_little_endian(vq), val); 264 } 265 266 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val) 267 { 268 return __cpu_to_virtio16(vhost_is_little_endian(vq), val); 269 } 270 271 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val) 272 { 273 return __virtio32_to_cpu(vhost_is_little_endian(vq), val); 274 } 275 276 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val) 277 { 278 return __cpu_to_virtio32(vhost_is_little_endian(vq), val); 279 } 280 281 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val) 282 { 283 return __virtio64_to_cpu(vhost_is_little_endian(vq), val); 284 } 285 286 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val) 287 { 288 return __cpu_to_virtio64(vhost_is_little_endian(vq), val); 289 } 290 #endif 291