drivers/vhost/vhost.h

   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 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
  20
  21 #define VHOST_WORK_QUEUED 1
  22 struct vhost_work {
  23         struct llist_node         node;
  24         vhost_work_fn_t           fn;
  25         unsigned long             flags;
  26 };
  27
  28 /* Poll a file (eventfd or socket) */
  29 /* Note: there's nothing vhost specific about this structure. */
  30 struct vhost_poll {
  31         poll_table                table;
  32         wait_queue_head_t        *wqh;
  33         wait_queue_entry_t              wait;
  34         struct vhost_work         work;
  35         __poll_t                  mask;
  36         struct vhost_dev         *dev;
  37 };
  38
  39 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
  40 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
  41 bool vhost_has_work(struct vhost_dev *dev);
  42
  43 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
  44                      __poll_t mask, struct vhost_dev *dev);
  45 int vhost_poll_start(struct vhost_poll *poll, struct file *file);
  46 void vhost_poll_stop(struct vhost_poll *poll);
  47 void vhost_poll_flush(struct vhost_poll *poll);
  48 void vhost_poll_queue(struct vhost_poll *poll);
  49 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work);
  50 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
  51
  52 struct vhost_log {
  53         u64 addr;
  54         u64 len;
  55 };
  56
  57 enum vhost_uaddr_type {
  58         VHOST_ADDR_DESC = 0,
  59         VHOST_ADDR_AVAIL = 1,
  60         VHOST_ADDR_USED = 2,
  61         VHOST_NUM_ADDRS = 3,
  62 };
  63
  64 struct vhost_vring_call {
  65         struct eventfd_ctx *ctx;
  66         struct irq_bypass_producer producer;
  67 };
  68
  69 /* The virtqueue structure describes a queue attached to a device. */
  70 struct vhost_virtqueue {
  71         struct vhost_dev *dev;
  72
  73         /* The actual ring of buffers. */
  74         struct mutex mutex;
  75         unsigned int num;
  76         vring_desc_t __user *desc;
  77         vring_avail_t __user *avail;
  78         vring_used_t __user *used;
  79         const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
  80         struct file *kick;
  81         struct vhost_vring_call call_ctx;
  82         struct eventfd_ctx *error_ctx;
  83         struct eventfd_ctx *log_ctx;
  84
  85         struct vhost_poll poll;
  86
  87         /* The routine to call when the Guest pings us, or timeout. */
  88         vhost_work_fn_t handle_kick;
  89
  90         /* Last available index we saw. */
  91         u16 last_avail_idx;
  92
  93         /* Caches available index value from user. */
  94         u16 avail_idx;
  95
  96         /* Last index we used. */
  97         u16 last_used_idx;
  98
  99         /* Used flags */
 100         u16 used_flags;
 101
 102         /* Last used index value we have signalled on */
 103         u16 signalled_used;
 104
 105         /* Last used index value we have signalled on */
 106         bool signalled_used_valid;
 107
 108         /* Log writes to used structure. */
 109         bool log_used;
 110         u64 log_addr;
 111
 112         struct iovec iov[UIO_MAXIOV];
 113         struct iovec iotlb_iov[64];
 114         struct iovec *indirect;
 115         struct vring_used_elem *heads;
 116         /* Protected by virtqueue mutex. */
 117         struct vhost_iotlb *umem;
 118         struct vhost_iotlb *iotlb;
 119         void *private_data;
 120         u64 acked_features;
 121         u64 acked_backend_features;
 122         /* Log write descriptors */
 123         void __user *log_base;
 124         struct vhost_log *log;
 125         struct iovec log_iov[64];
 126
 127         /* Ring endianness. Defaults to legacy native endianness.
 128          * Set to true when starting a modern virtio device. */
 129         bool is_le;
 130 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 131         /* Ring endianness requested by userspace for cross-endian support. */
 132         bool user_be;
 133 #endif
 134         u32 busyloop_timeout;
 135 };
 136
 137 struct vhost_msg_node {
 138   union {
 139           struct vhost_msg msg;
 140           struct vhost_msg_v2 msg_v2;
 141   };
 142   struct vhost_virtqueue *vq;
 143   struct list_head node;
 144 };
 145
 146 struct vhost_dev {
 147         struct mm_struct *mm;
 148         struct mutex mutex;
 149         struct vhost_virtqueue **vqs;
 150         int nvqs;
 151         struct eventfd_ctx *log_ctx;
 152         struct llist_head work_list;
 153         struct task_struct *worker;
 154         struct vhost_iotlb *umem;
 155         struct vhost_iotlb *iotlb;
 156         spinlock_t iotlb_lock;
 157         struct list_head read_list;
 158         struct list_head pending_list;
 159         wait_queue_head_t wait;
 160         int iov_limit;
 161         int weight;
 162         int byte_weight;
 163         u64 kcov_handle;
 164         bool use_worker;
 165         int (*msg_handler)(struct vhost_dev *dev,
 166                            struct vhost_iotlb_msg *msg);
 167 };
 168
 169 bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
 170 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
 171                     int nvqs, int iov_limit, int weight, int byte_weight,
 172                     bool use_worker,
 173                     int (*msg_handler)(struct vhost_dev *dev,
 174                                        struct vhost_iotlb_msg *msg));
 175 long vhost_dev_set_owner(struct vhost_dev *dev);
 176 bool vhost_dev_has_owner(struct vhost_dev *dev);
 177 long vhost_dev_check_owner(struct vhost_dev *);
 178 struct vhost_iotlb *vhost_dev_reset_owner_prepare(void);
 179 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *iotlb);
 180 void vhost_dev_cleanup(struct vhost_dev *);
 181 void vhost_dev_stop(struct vhost_dev *);
 182 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
 183 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
 184 bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
 185 bool vhost_log_access_ok(struct vhost_dev *);
 186
 187 int vhost_get_vq_desc(struct vhost_virtqueue *,
 188                       struct iovec iov[], unsigned int iov_count,
 189                       unsigned int *out_num, unsigned int *in_num,
 190                       struct vhost_log *log, unsigned int *log_num);
 191 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 192
 193 bool vhost_vq_is_setup(struct vhost_virtqueue *vq);
 194 int vhost_vq_init_access(struct vhost_virtqueue *);
 195 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 196 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 197                      unsigned count);
 198 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 199                                unsigned int id, int len);
 200 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 201                                struct vring_used_elem *heads, unsigned count);
 202 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 203 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 204 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
 205 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 206
 207 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 208                     unsigned int log_num, u64 len,
 209                     struct iovec *iov, int count);
 210 int vq_meta_prefetch(struct vhost_virtqueue *vq);
 211
 212 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
 213 void vhost_enqueue_msg(struct vhost_dev *dev,
 214                        struct list_head *head,
 215                        struct vhost_msg_node *node);
 216 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
 217                                          struct list_head *head);
 218 void vhost_set_backend_features(struct vhost_dev *dev, u64 features);
 219
 220 __poll_t 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 void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
 229                           struct vhost_iotlb_map *map);
 230
 231 #define vq_err(vq, fmt, ...) do {                                  \
 232                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 233                 if ((vq)->error_ctx)                               \
 234                                 eventfd_signal((vq)->error_ctx, 1);\
 235         } while (0)
 236
 237 enum {
 238         VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 239                          (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 240                          (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 241                          (1ULL << VHOST_F_LOG_ALL) |
 242                          (1ULL << VIRTIO_F_ANY_LAYOUT) |
 243                          (1ULL << VIRTIO_F_VERSION_1)
 244 };
 245
 246 /**
 247  * vhost_vq_set_backend - Set backend.
 248  *
 249  * @vq            Virtqueue.
 250  * @private_data  The private data.
 251  *
 252  * Context: Need to call with vq->mutex acquired.
 253  */
 254 static inline void vhost_vq_set_backend(struct vhost_virtqueue *vq,
 255                                         void *private_data)
 256 {
 257         vq->private_data = private_data;
 258 }
 259
 260 /**
 261  * vhost_vq_get_backend - Get backend.
 262  *
 263  * @vq            Virtqueue.
 264  *
 265  * Context: Need to call with vq->mutex acquired.
 266  * Return: Private data previously set with vhost_vq_set_backend.
 267  */
 268 static inline void *vhost_vq_get_backend(struct vhost_virtqueue *vq)
 269 {
 270         return vq->private_data;
 271 }
 272
 273 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
 274 {
 275         return vq->acked_features & (1ULL << bit);
 276 }
 277
 278 static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
 279 {
 280         return vq->acked_backend_features & (1ULL << bit);
 281 }
 282
 283 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 284 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 285 {
 286         return vq->is_le;
 287 }
 288 #else
 289 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 290 {
 291         return virtio_legacy_is_little_endian() || vq->is_le;
 292 }
 293 #endif
 294
 295 /* Memory accessors */
 296 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
 297 {
 298         return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
 299 }
 300
 301 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
 302 {
 303         return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
 304 }
 305
 306 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
 307 {
 308         return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
 309 }
 310
 311 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
 312 {
 313         return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
 314 }
 315
 316 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
 317 {
 318         return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
 319 }
 320
 321 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
 322 {
 323         return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
 324 }
 325 #endif