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 struct vhost_work {
  19         struct list_head          node;
  20         vhost_work_fn_t           fn;
  21         wait_queue_head_t         done;
  22         int                       flushing;
  23         unsigned                  queue_seq;
  24         unsigned                  done_seq;
  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_t              wait;
  33         struct vhost_work         work;
  34         unsigned long             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
  41 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
  42                      unsigned long mask, struct vhost_dev *dev);
  43 int vhost_poll_start(struct vhost_poll *poll, struct file *file);
  44 void vhost_poll_stop(struct vhost_poll *poll);
  45 void vhost_poll_flush(struct vhost_poll *poll);
  46 void vhost_poll_queue(struct vhost_poll *poll);
  47 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work);
  48 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
  49
  50 struct vhost_log {
  51         u64 addr;
  52         u64 len;
  53 };
  54
  55 /* The virtqueue structure describes a queue attached to a device. */
  56 struct vhost_virtqueue {
  57         struct vhost_dev *dev;
  58
  59         /* The actual ring of buffers. */
  60         struct mutex mutex;
  61         unsigned int num;
  62         struct vring_desc __user *desc;
  63         struct vring_avail __user *avail;
  64         struct vring_used __user *used;
  65         struct file *kick;
  66         struct file *call;
  67         struct file *error;
  68         struct eventfd_ctx *call_ctx;
  69         struct eventfd_ctx *error_ctx;
  70         struct eventfd_ctx *log_ctx;
  71
  72         struct vhost_poll poll;
  73
  74         /* The routine to call when the Guest pings us, or timeout. */
  75         vhost_work_fn_t handle_kick;
  76
  77         /* Last available index we saw. */
  78         u16 last_avail_idx;
  79
  80         /* Caches available index value from user. */
  81         u16 avail_idx;
  82
  83         /* Last index we used. */
  84         u16 last_used_idx;
  85
  86         /* Used flags */
  87         u16 used_flags;
  88
  89         /* Last used index value we have signalled on */
  90         u16 signalled_used;
  91
  92         /* Last used index value we have signalled on */
  93         bool signalled_used_valid;
  94
  95         /* Log writes to used structure. */
  96         bool log_used;
  97         u64 log_addr;
  98
  99         struct iovec iov[UIO_MAXIOV];
 100         struct iovec *indirect;
 101         struct vring_used_elem *heads;
 102         /* Protected by virtqueue mutex. */
 103         struct vhost_memory *memory;
 104         void *private_data;
 105         u64 acked_features;
 106         /* Log write descriptors */
 107         void __user *log_base;
 108         struct vhost_log *log;
 109
 110         /* Ring endianness. Defaults to legacy native endianness.
 111          * Set to true when starting a modern virtio device. */
 112         bool is_le;
 113 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 114         /* Ring endianness requested by userspace for cross-endian support. */
 115         bool user_be;
 116 #endif
 117 };
 118
 119 struct vhost_dev {
 120         struct vhost_memory *memory;
 121         struct mm_struct *mm;
 122         struct mutex mutex;
 123         struct vhost_virtqueue **vqs;
 124         int nvqs;
 125         struct file *log_file;
 126         struct eventfd_ctx *log_ctx;
 127         spinlock_t work_lock;
 128         struct list_head work_list;
 129         struct task_struct *worker;
 130 };
 131
 132 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
 133 long vhost_dev_set_owner(struct vhost_dev *dev);
 134 bool vhost_dev_has_owner(struct vhost_dev *dev);
 135 long vhost_dev_check_owner(struct vhost_dev *);
 136 struct vhost_memory *vhost_dev_reset_owner_prepare(void);
 137 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_memory *);
 138 void vhost_dev_cleanup(struct vhost_dev *, bool locked);
 139 void vhost_dev_stop(struct vhost_dev *);
 140 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
 141 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
 142 int vhost_vq_access_ok(struct vhost_virtqueue *vq);
 143 int vhost_log_access_ok(struct vhost_dev *);
 144
 145 int vhost_get_vq_desc(struct vhost_virtqueue *,
 146                       struct iovec iov[], unsigned int iov_count,
 147                       unsigned int *out_num, unsigned int *in_num,
 148                       struct vhost_log *log, unsigned int *log_num);
 149 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 150
 151 int vhost_init_used(struct vhost_virtqueue *);
 152 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 153 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 154                      unsigned count);
 155 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 156                                unsigned int id, int len);
 157 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 158                                struct vring_used_elem *heads, unsigned count);
 159 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 160 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 161 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 162
 163 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 164                     unsigned int log_num, u64 len);
 165
 166 #define vq_err(vq, fmt, ...) do {                                  \
 167                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 168                 if ((vq)->error_ctx)                               \
 169                                 eventfd_signal((vq)->error_ctx, 1);\
 170         } while (0)
 171
 172 enum {
 173         VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 174                          (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 175                          (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 176                          (1ULL << VHOST_F_LOG_ALL) |
 177                          (1ULL << VIRTIO_F_ANY_LAYOUT) |
 178                          (1ULL << VIRTIO_F_VERSION_1)
 179 };
 180
 181 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
 182 {
 183         return vq->acked_features & (1ULL << bit);
 184 }
 185
 186 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 187 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 188 {
 189         return vq->is_le;
 190 }
 191 #else
 192 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 193 {
 194         return virtio_legacy_is_little_endian() || vq->is_le;
 195 }
 196 #endif
 197
 198 /* Memory accessors */
 199 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
 200 {
 201         return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
 202 }
 203
 204 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
 205 {
 206         return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
 207 }
 208
 209 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
 210 {
 211         return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
 212 }
 213
 214 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
 215 {
 216         return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
 217 }
 218
 219 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
 220 {
 221         return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
 222 }
 223
 224 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
 225 {
 226         return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
 227 }
 228 #endif