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 #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         __u64 flags_padding;
  69         __u64 __subtree_last;
  70 };
  71
  72 struct vhost_umem {
  73         struct rb_root umem_tree;
  74         struct list_head umem_list;
  75 };
  76
  77 /* The virtqueue structure describes a queue attached to a device. */
  78 struct vhost_virtqueue {
  79         struct vhost_dev *dev;
  80
  81         /* The actual ring of buffers. */
  82         struct mutex mutex;
  83         unsigned int num;
  84         struct vring_desc __user *desc;
  85         struct vring_avail __user *avail;
  86         struct vring_used __user *used;
  87         struct file *kick;
  88         struct file *call;
  89         struct file *error;
  90         struct eventfd_ctx *call_ctx;
  91         struct eventfd_ctx *error_ctx;
  92         struct eventfd_ctx *log_ctx;
  93
  94         struct vhost_poll poll;
  95
  96         /* The routine to call when the Guest pings us, or timeout. */
  97         vhost_work_fn_t handle_kick;
  98
  99         /* Last available index we saw. */
 100         u16 last_avail_idx;
 101
 102         /* Caches available index value from user. */
 103         u16 avail_idx;
 104
 105         /* Last index we used. */
 106         u16 last_used_idx;
 107
 108         /* Used flags */
 109         u16 used_flags;
 110
 111         /* Last used index value we have signalled on */
 112         u16 signalled_used;
 113
 114         /* Last used index value we have signalled on */
 115         bool signalled_used_valid;
 116
 117         /* Log writes to used structure. */
 118         bool log_used;
 119         u64 log_addr;
 120
 121         struct iovec iov[UIO_MAXIOV];
 122         struct iovec *indirect;
 123         struct vring_used_elem *heads;
 124         /* Protected by virtqueue mutex. */
 125         struct vhost_umem *umem;
 126         void *private_data;
 127         u64 acked_features;
 128         /* Log write descriptors */
 129         void __user *log_base;
 130         struct vhost_log *log;
 131
 132         /* Ring endianness. Defaults to legacy native endianness.
 133          * Set to true when starting a modern virtio device. */
 134         bool is_le;
 135 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 136         /* Ring endianness requested by userspace for cross-endian support. */
 137         bool user_be;
 138 #endif
 139         u32 busyloop_timeout;
 140 };
 141
 142 struct vhost_dev {
 143         struct mm_struct *mm;
 144         struct mutex mutex;
 145         struct vhost_virtqueue **vqs;
 146         int nvqs;
 147         struct file *log_file;
 148         struct eventfd_ctx *log_ctx;
 149         struct llist_head work_list;
 150         struct task_struct *worker;
 151         struct vhost_umem *umem;
 152 };
 153
 154 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
 155 long vhost_dev_set_owner(struct vhost_dev *dev);
 156 bool vhost_dev_has_owner(struct vhost_dev *dev);
 157 long vhost_dev_check_owner(struct vhost_dev *);
 158 struct vhost_umem *vhost_dev_reset_owner_prepare(void);
 159 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_umem *);
 160 void vhost_dev_cleanup(struct vhost_dev *, bool locked);
 161 void vhost_dev_stop(struct vhost_dev *);
 162 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
 163 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
 164 int vhost_vq_access_ok(struct vhost_virtqueue *vq);
 165 int vhost_log_access_ok(struct vhost_dev *);
 166
 167 int vhost_get_vq_desc(struct vhost_virtqueue *,
 168                       struct iovec iov[], unsigned int iov_count,
 169                       unsigned int *out_num, unsigned int *in_num,
 170                       struct vhost_log *log, unsigned int *log_num);
 171 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 172
 173 int vhost_vq_init_access(struct vhost_virtqueue *);
 174 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 175 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 176                      unsigned count);
 177 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 178                                unsigned int id, int len);
 179 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 180                                struct vring_used_elem *heads, unsigned count);
 181 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 182 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 183 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
 184 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 185
 186 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 187                     unsigned int log_num, u64 len);
 188
 189 #define vq_err(vq, fmt, ...) do {                                  \
 190                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 191                 if ((vq)->error_ctx)                               \
 192                                 eventfd_signal((vq)->error_ctx, 1);\
 193         } while (0)
 194
 195 enum {
 196         VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 197                          (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 198                          (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 199                          (1ULL << VHOST_F_LOG_ALL) |
 200                          (1ULL << VIRTIO_F_ANY_LAYOUT) |
 201                          (1ULL << VIRTIO_F_VERSION_1)
 202 };
 203
 204 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
 205 {
 206         return vq->acked_features & (1ULL << bit);
 207 }
 208
 209 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 210 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 211 {
 212         return vq->is_le;
 213 }
 214 #else
 215 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 216 {
 217         return virtio_legacy_is_little_endian() || vq->is_le;
 218 }
 219 #endif
 220
 221 /* Memory accessors */
 222 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
 223 {
 224         return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
 225 }
 226
 227 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
 228 {
 229         return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
 230 }
 231
 232 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
 233 {
 234         return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
 235 }
 236
 237 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
 238 {
 239         return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
 240 }
 241
 242 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
 243 {
 244         return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
 245 }
 246
 247 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
 248 {
 249         return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
 250 }
 251 #endif