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 bool vhost_has_work(struct vhost_dev *dev);
  41
  42 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
  43                      unsigned long 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, int ioctl, void __user *argp);
  50
  51 struct vhost_log {
  52         u64 addr;
  53         u64 len;
  54 };
  55
  56 /* The virtqueue structure describes a queue attached to a device. */
  57 struct vhost_virtqueue {
  58         struct vhost_dev *dev;
  59
  60         /* The actual ring of buffers. */
  61         struct mutex mutex;
  62         unsigned int num;
  63         struct vring_desc __user *desc;
  64         struct vring_avail __user *avail;
  65         struct vring_used __user *used;
  66         struct file *kick;
  67         struct file *call;
  68         struct file *error;
  69         struct eventfd_ctx *call_ctx;
  70         struct eventfd_ctx *error_ctx;
  71         struct eventfd_ctx *log_ctx;
  72
  73         struct vhost_poll poll;
  74
  75         /* The routine to call when the Guest pings us, or timeout. */
  76         vhost_work_fn_t handle_kick;
  77
  78         /* Last available index we saw. */
  79         u16 last_avail_idx;
  80
  81         /* Caches available index value from user. */
  82         u16 avail_idx;
  83
  84         /* Last index we used. */
  85         u16 last_used_idx;
  86
  87         /* Used flags */
  88         u16 used_flags;
  89
  90         /* Last used index value we have signalled on */
  91         u16 signalled_used;
  92
  93         /* Last used index value we have signalled on */
  94         bool signalled_used_valid;
  95
  96         /* Log writes to used structure. */
  97         bool log_used;
  98         u64 log_addr;
  99
 100         struct iovec iov[UIO_MAXIOV];
 101         struct iovec *indirect;
 102         struct vring_used_elem *heads;
 103         /* Protected by virtqueue mutex. */
 104         struct vhost_memory *memory;
 105         void *private_data;
 106         u64 acked_features;
 107         /* Log write descriptors */
 108         void __user *log_base;
 109         struct vhost_log *log;
 110
 111         /* Ring endianness. Defaults to legacy native endianness.
 112          * Set to true when starting a modern virtio device. */
 113         bool is_le;
 114 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 115         /* Ring endianness requested by userspace for cross-endian support. */
 116         bool user_be;
 117 #endif
 118         u32 busyloop_timeout;
 119 };
 120
 121 struct vhost_dev {
 122         struct vhost_memory *memory;
 123         struct mm_struct *mm;
 124         struct mutex mutex;
 125         struct vhost_virtqueue **vqs;
 126         int nvqs;
 127         struct file *log_file;
 128         struct eventfd_ctx *log_ctx;
 129         spinlock_t work_lock;
 130         struct list_head work_list;
 131         struct task_struct *worker;
 132 };
 133
 134 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
 135 long vhost_dev_set_owner(struct vhost_dev *dev);
 136 bool vhost_dev_has_owner(struct vhost_dev *dev);
 137 long vhost_dev_check_owner(struct vhost_dev *);
 138 struct vhost_memory *vhost_dev_reset_owner_prepare(void);
 139 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_memory *);
 140 void vhost_dev_cleanup(struct vhost_dev *, bool locked);
 141 void vhost_dev_stop(struct vhost_dev *);
 142 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
 143 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
 144 int vhost_vq_access_ok(struct vhost_virtqueue *vq);
 145 int vhost_log_access_ok(struct vhost_dev *);
 146
 147 int vhost_get_vq_desc(struct vhost_virtqueue *,
 148                       struct iovec iov[], unsigned int iov_count,
 149                       unsigned int *out_num, unsigned int *in_num,
 150                       struct vhost_log *log, unsigned int *log_num);
 151 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 152
 153 int vhost_vq_init_access(struct vhost_virtqueue *);
 154 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 155 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 156                      unsigned count);
 157 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 158                                unsigned int id, int len);
 159 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 160                                struct vring_used_elem *heads, unsigned count);
 161 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 162 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 163 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
 164 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 165
 166 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 167                     unsigned int log_num, u64 len);
 168
 169 #define vq_err(vq, fmt, ...) do {                                  \
 170                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 171                 if ((vq)->error_ctx)                               \
 172                                 eventfd_signal((vq)->error_ctx, 1);\
 173         } while (0)
 174
 175 enum {
 176         VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 177                          (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 178                          (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 179                          (1ULL << VHOST_F_LOG_ALL) |
 180                          (1ULL << VIRTIO_F_ANY_LAYOUT) |
 181                          (1ULL << VIRTIO_F_VERSION_1)
 182 };
 183
 184 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
 185 {
 186         return vq->acked_features & (1ULL << bit);
 187 }
 188
 189 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 190 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 191 {
 192         return vq->is_le;
 193 }
 194 #else
 195 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 196 {
 197         return virtio_legacy_is_little_endian() || vq->is_le;
 198 }
 199 #endif
 200
 201 /* Memory accessors */
 202 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
 203 {
 204         return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
 205 }
 206
 207 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
 208 {
 209         return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
 210 }
 211
 212 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
 213 {
 214         return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
 215 }
 216
 217 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
 218 {
 219         return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
 220 }
 221
 222 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
 223 {
 224         return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
 225 }
 226
 227 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
 228 {
 229         return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
 230 }
 231 #endif