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