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
  17 struct vhost_work;
  18 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
  19
  20 #define VHOST_WORK_QUEUED 1
  21 struct vhost_work {
  22         struct llist_node         node;
  23         vhost_work_fn_t           fn;
  24         unsigned long             flags;
  25 };
  26
  27 /* Poll a file (eventfd or socket) */
  28 /* Note: there's nothing vhost specific about this structure. */
  29 struct vhost_poll {
  30         poll_table                table;
  31         wait_queue_head_t        *wqh;
  32         wait_queue_entry_t              wait;
  33         struct vhost_work         work;
  34         __poll_t                  mask;
  35         struct vhost_dev         *dev;
  36 };
  37
  38 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
  39 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
  40 bool vhost_has_work(struct vhost_dev *dev);
  41
  42 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
  43                      __poll_t mask, struct vhost_dev *dev);
  44 int vhost_poll_start(struct vhost_poll *poll, struct file *file);
  45 void vhost_poll_stop(struct vhost_poll *poll);
  46 void vhost_poll_flush(struct vhost_poll *poll);
  47 void vhost_poll_queue(struct vhost_poll *poll);
  48 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work);
  49 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
  50
  51 struct vhost_log {
  52         u64 addr;
  53         u64 len;
  54 };
  55
  56 enum vhost_uaddr_type {
  57         VHOST_ADDR_DESC = 0,
  58         VHOST_ADDR_AVAIL = 1,
  59         VHOST_ADDR_USED = 2,
  60         VHOST_NUM_ADDRS = 3,
  61 };
  62
  63 /* The virtqueue structure describes a queue attached to a device. */
  64 struct vhost_virtqueue {
  65         struct vhost_dev *dev;
  66
  67         /* The actual ring of buffers. */
  68         struct mutex mutex;
  69         unsigned int num;
  70         struct vring_desc __user *desc;
  71         struct vring_avail __user *avail;
  72         struct vring_used __user *used;
  73         const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
  74         struct file *kick;
  75         struct eventfd_ctx *call_ctx;
  76         struct eventfd_ctx *error_ctx;
  77         struct eventfd_ctx *log_ctx;
  78
  79         struct vhost_poll poll;
  80
  81         /* The routine to call when the Guest pings us, or timeout. */
  82         vhost_work_fn_t handle_kick;
  83
  84         /* Last available index we saw. */
  85         u16 last_avail_idx;
  86
  87         /* Caches available index value from user. */
  88         u16 avail_idx;
  89
  90         /* Last index we used. */
  91         u16 last_used_idx;
  92
  93         /* Used flags */
  94         u16 used_flags;
  95
  96         /* Last used index value we have signalled on */
  97         u16 signalled_used;
  98
  99         /* Last used index value we have signalled on */
 100         bool signalled_used_valid;
 101
 102         /* Log writes to used structure. */
 103         bool log_used;
 104         u64 log_addr;
 105
 106         struct iovec iov[UIO_MAXIOV];
 107         struct iovec iotlb_iov[64];
 108         struct iovec *indirect;
 109         struct vring_used_elem *heads;
 110         /* Protected by virtqueue mutex. */
 111         struct vhost_iotlb *umem;
 112         struct vhost_iotlb *iotlb;
 113         void *private_data;
 114         u64 acked_features;
 115         u64 acked_backend_features;
 116         /* Log write descriptors */
 117         void __user *log_base;
 118         struct vhost_log *log;
 119
 120         /* Ring endianness. Defaults to legacy native endianness.
 121          * Set to true when starting a modern virtio device. */
 122         bool is_le;
 123 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 124         /* Ring endianness requested by userspace for cross-endian support. */
 125         bool user_be;
 126 #endif
 127         u32 busyloop_timeout;
 128 };
 129
 130 struct vhost_msg_node {
 131   union {
 132           struct vhost_msg msg;
 133           struct vhost_msg_v2 msg_v2;
 134   };
 135   struct vhost_virtqueue *vq;
 136   struct list_head node;
 137 };
 138
 139 struct vhost_dev {
 140         struct mm_struct *mm;
 141         struct mutex mutex;
 142         struct vhost_virtqueue **vqs;
 143         int nvqs;
 144         struct eventfd_ctx *log_ctx;
 145         struct llist_head work_list;
 146         struct task_struct *worker;
 147         struct vhost_iotlb *umem;
 148         struct vhost_iotlb *iotlb;
 149         spinlock_t iotlb_lock;
 150         struct list_head read_list;
 151         struct list_head pending_list;
 152         wait_queue_head_t wait;
 153         int iov_limit;
 154         int weight;
 155         int byte_weight;
 156         u64 kcov_handle;
 157         int (*msg_handler)(struct vhost_dev *dev,
 158                            struct vhost_iotlb_msg *msg);
 159 };
 160
 161 bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
 162 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
 163                     int nvqs, int iov_limit, int weight, int byte_weight,
 164                     int (*msg_handler)(struct vhost_dev *dev,
 165                                        struct vhost_iotlb_msg *msg));
 166 long vhost_dev_set_owner(struct vhost_dev *dev);
 167 bool vhost_dev_has_owner(struct vhost_dev *dev);
 168 long vhost_dev_check_owner(struct vhost_dev *);
 169 struct vhost_iotlb *vhost_dev_reset_owner_prepare(void);
 170 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *iotlb);
 171 void vhost_dev_cleanup(struct vhost_dev *);
 172 void vhost_dev_stop(struct vhost_dev *);
 173 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
 174 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
 175 bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
 176 bool vhost_log_access_ok(struct vhost_dev *);
 177
 178 int vhost_get_vq_desc(struct vhost_virtqueue *,
 179                       struct iovec iov[], unsigned int iov_count,
 180                       unsigned int *out_num, unsigned int *in_num,
 181                       struct vhost_log *log, unsigned int *log_num);
 182 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 183
 184 int vhost_vq_init_access(struct vhost_virtqueue *);
 185 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 186 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 187                      unsigned count);
 188 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 189                                unsigned int id, int len);
 190 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 191                                struct vring_used_elem *heads, unsigned count);
 192 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 193 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 194 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
 195 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 196
 197 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 198                     unsigned int log_num, u64 len,
 199                     struct iovec *iov, int count);
 200 int vq_meta_prefetch(struct vhost_virtqueue *vq);
 201
 202 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
 203 void vhost_enqueue_msg(struct vhost_dev *dev,
 204                        struct list_head *head,
 205                        struct vhost_msg_node *node);
 206 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
 207                                          struct list_head *head);
 208 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
 209                             poll_table *wait);
 210 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
 211                             int noblock);
 212 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
 213                              struct iov_iter *from);
 214 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
 215
 216 void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
 217                           struct vhost_iotlb_map *map);
 218
 219 #define vq_err(vq, fmt, ...) do {                                  \
 220                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 221                 if ((vq)->error_ctx)                               \
 222                                 eventfd_signal((vq)->error_ctx, 1);\
 223         } while (0)
 224
 225 enum {
 226         VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 227                          (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 228                          (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 229                          (1ULL << VHOST_F_LOG_ALL) |
 230                          (1ULL << VIRTIO_F_ANY_LAYOUT) |
 231                          (1ULL << VIRTIO_F_VERSION_1)
 232 };
 233
 234 /**
 235  * vhost_vq_set_backend - Set backend.
 236  *
 237  * @vq            Virtqueue.
 238  * @private_data  The private data.
 239  *
 240  * Context: Need to call with vq->mutex acquired.
 241  */
 242 static inline void vhost_vq_set_backend(struct vhost_virtqueue *vq,
 243                                         void *private_data)
 244 {
 245         vq->private_data = private_data;
 246 }
 247
 248 /**
 249  * vhost_vq_get_backend - Get backend.
 250  *
 251  * @vq            Virtqueue.
 252  *
 253  * Context: Need to call with vq->mutex acquired.
 254  * Return: Private data previously set with vhost_vq_set_backend.
 255  */
 256 static inline void *vhost_vq_get_backend(struct vhost_virtqueue *vq)
 257 {
 258         return vq->private_data;
 259 }
 260
 261 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
 262 {
 263         return vq->acked_features & (1ULL << bit);
 264 }
 265
 266 static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
 267 {
 268         return vq->acked_backend_features & (1ULL << bit);
 269 }
 270
 271 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 272 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 273 {
 274         return vq->is_le;
 275 }
 276 #else
 277 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 278 {
 279         return virtio_legacy_is_little_endian() || vq->is_le;
 280 }
 281 #endif
 282
 283 /* Memory accessors */
 284 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
 285 {
 286         return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
 287 }
 288
 289 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
 290 {
 291         return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
 292 }
 293
 294 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
 295 {
 296         return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
 297 }
 298
 299 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
 300 {
 301         return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
 302 }
 303
 304 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
 305 {
 306         return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
 307 }
 308
 309 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
 310 {
 311         return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
 312 }
 313 #endif