drivers/vhost/vhost.h

   1 #ifndef _VHOST_H
   2 #define _VHOST_H
   3
   4 #include <linux/eventfd.h>
   5 #include <linux/vhost.h>
   6 #include <linux/mm.h>
   7 #include <linux/mutex.h>
   8 #include <linux/poll.h>
   9 #include <linux/file.h>
  10 #include <linux/uio.h>
  11 #include <linux/virtio_config.h>
  12 #include <linux/virtio_ring.h>
  13 #include <linux/atomic.h>
  14
  15 struct vhost_work;
  16 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
  17
  18 #define VHOST_WORK_QUEUED 1
  19 struct vhost_work {
  20         struct llist_node         node;
  21         vhost_work_fn_t           fn;
  22         wait_queue_head_t         done;
  23         int                       flushing;
  24         unsigned                  queue_seq;
  25         unsigned                  done_seq;
  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         unsigned long             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                      unsigned long 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, 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 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 /* The virtqueue structure describes a queue attached to a device. */
  87 struct vhost_virtqueue {
  88         struct vhost_dev *dev;
  89
  90         /* The actual ring of buffers. */
  91         struct mutex mutex;
  92         unsigned int num;
  93         struct vring_desc __user *desc;
  94         struct vring_avail __user *avail;
  95         struct vring_used __user *used;
  96         const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS];
  97         struct file *kick;
  98         struct file *call;
  99         struct file *error;
 100         struct eventfd_ctx *call_ctx;
 101         struct eventfd_ctx *error_ctx;
 102         struct eventfd_ctx *log_ctx;
 103
 104         struct vhost_poll poll;
 105
 106         /* The routine to call when the Guest pings us, or timeout. */
 107         vhost_work_fn_t handle_kick;
 108
 109         /* Last available index we saw. */
 110         u16 last_avail_idx;
 111
 112         /* Caches available index value from user. */
 113         u16 avail_idx;
 114
 115         /* Last index we used. */
 116         u16 last_used_idx;
 117
 118         /* Used flags */
 119         u16 used_flags;
 120
 121         /* Last used index value we have signalled on */
 122         u16 signalled_used;
 123
 124         /* Last used index value we have signalled on */
 125         bool signalled_used_valid;
 126
 127         /* Log writes to used structure. */
 128         bool log_used;
 129         u64 log_addr;
 130
 131         struct iovec iov[UIO_MAXIOV];
 132         struct iovec iotlb_iov[64];
 133         struct iovec *indirect;
 134         struct vring_used_elem *heads;
 135         /* Protected by virtqueue mutex. */
 136         struct vhost_umem *umem;
 137         struct vhost_umem *iotlb;
 138         void *private_data;
 139         u64 acked_features;
 140         /* Log write descriptors */
 141         void __user *log_base;
 142         struct vhost_log *log;
 143
 144         /* Ring endianness. Defaults to legacy native endianness.
 145          * Set to true when starting a modern virtio device. */
 146         bool is_le;
 147 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 148         /* Ring endianness requested by userspace for cross-endian support. */
 149         bool user_be;
 150 #endif
 151         u32 busyloop_timeout;
 152 };
 153
 154 struct vhost_msg_node {
 155   struct vhost_msg msg;
 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 file *log_file;
 166         struct eventfd_ctx *log_ctx;
 167         struct llist_head work_list;
 168         struct task_struct *worker;
 169         struct vhost_umem *umem;
 170         struct vhost_umem *iotlb;
 171         spinlock_t iotlb_lock;
 172         struct list_head read_list;
 173         struct list_head pending_list;
 174         wait_queue_head_t wait;
 175 };
 176
 177 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
 178 long vhost_dev_set_owner(struct vhost_dev *dev);
 179 bool vhost_dev_has_owner(struct vhost_dev *dev);
 180 long vhost_dev_check_owner(struct vhost_dev *);
 181 struct vhost_umem *vhost_dev_reset_owner_prepare(void);
 182 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_umem *);
 183 void vhost_dev_cleanup(struct vhost_dev *, bool locked);
 184 void vhost_dev_stop(struct vhost_dev *);
 185 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
 186 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
 187 int vhost_vq_access_ok(struct vhost_virtqueue *vq);
 188 int vhost_log_access_ok(struct vhost_dev *);
 189
 190 int vhost_get_vq_desc(struct vhost_virtqueue *,
 191                       struct iovec iov[], unsigned int iov_count,
 192                       unsigned int *out_num, unsigned int *in_num,
 193                       struct vhost_log *log, unsigned int *log_num);
 194 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 195
 196 int vhost_vq_init_access(struct vhost_virtqueue *);
 197 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 198 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 199                      unsigned count);
 200 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 201                                unsigned int id, int len);
 202 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 203                                struct vring_used_elem *heads, unsigned count);
 204 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 205 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 206 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
 207 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 208
 209 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 210                     unsigned int log_num, u64 len);
 211 int vq_iotlb_prefetch(struct vhost_virtqueue *vq);
 212
 213 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
 214 void vhost_enqueue_msg(struct vhost_dev *dev,
 215                        struct list_head *head,
 216                        struct vhost_msg_node *node);
 217 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
 218                                          struct list_head *head);
 219 unsigned int vhost_chr_poll(struct file *file, struct vhost_dev *dev,
 220                             poll_table *wait);
 221 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
 222                             int noblock);
 223 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
 224                              struct iov_iter *from);
 225 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
 226
 227 #define vq_err(vq, fmt, ...) do {                                  \
 228                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 229                 if ((vq)->error_ctx)                               \
 230                                 eventfd_signal((vq)->error_ctx, 1);\
 231         } while (0)
 232
 233 enum {
 234         VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 235                          (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 236                          (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 237                          (1ULL << VHOST_F_LOG_ALL) |
 238                          (1ULL << VIRTIO_F_ANY_LAYOUT) |
 239                          (1ULL << VIRTIO_F_VERSION_1)
 240 };
 241
 242 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
 243 {
 244         return vq->acked_features & (1ULL << bit);
 245 }
 246
 247 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 248 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 249 {
 250         return vq->is_le;
 251 }
 252 #else
 253 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 254 {
 255         return virtio_legacy_is_little_endian() || vq->is_le;
 256 }
 257 #endif
 258
 259 /* Memory accessors */
 260 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
 261 {
 262         return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
 263 }
 264
 265 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
 266 {
 267         return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
 268 }
 269
 270 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
 271 {
 272         return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
 273 }
 274
 275 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
 276 {
 277         return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
 278 }
 279
 280 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
 281 {
 282         return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
 283 }
 284
 285 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
 286 {
 287         return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
 288 }
 289 #endif