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         __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 /* The virtqueue structure describes a queue attached to a device. */
  80 struct vhost_virtqueue {
  81         struct vhost_dev *dev;
  82
  83         /* The actual ring of buffers. */
  84         struct mutex mutex;
  85         unsigned int num;
  86         struct vring_desc __user *desc;
  87         struct vring_avail __user *avail;
  88         struct vring_used __user *used;
  89         struct file *kick;
  90         struct file *call;
  91         struct file *error;
  92         struct eventfd_ctx *call_ctx;
  93         struct eventfd_ctx *error_ctx;
  94         struct eventfd_ctx *log_ctx;
  95
  96         struct vhost_poll poll;
  97
  98         /* The routine to call when the Guest pings us, or timeout. */
  99         vhost_work_fn_t handle_kick;
 100
 101         /* Last available index we saw. */
 102         u16 last_avail_idx;
 103
 104         /* Caches available index value from user. */
 105         u16 avail_idx;
 106
 107         /* Last index we used. */
 108         u16 last_used_idx;
 109
 110         /* Used flags */
 111         u16 used_flags;
 112
 113         /* Last used index value we have signalled on */
 114         u16 signalled_used;
 115
 116         /* Last used index value we have signalled on */
 117         bool signalled_used_valid;
 118
 119         /* Log writes to used structure. */
 120         bool log_used;
 121         u64 log_addr;
 122
 123         struct iovec iov[UIO_MAXIOV];
 124         struct iovec iotlb_iov[64];
 125         struct iovec *indirect;
 126         struct vring_used_elem *heads;
 127         /* Protected by virtqueue mutex. */
 128         struct vhost_umem *umem;
 129         struct vhost_umem *iotlb;
 130         void *private_data;
 131         u64 acked_features;
 132         /* Log write descriptors */
 133         void __user *log_base;
 134         struct vhost_log *log;
 135
 136         /* Ring endianness. Defaults to legacy native endianness.
 137          * Set to true when starting a modern virtio device. */
 138         bool is_le;
 139 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 140         /* Ring endianness requested by userspace for cross-endian support. */
 141         bool user_be;
 142 #endif
 143         u32 busyloop_timeout;
 144 };
 145
 146 struct vhost_msg_node {
 147   struct vhost_msg msg;
 148   struct vhost_virtqueue *vq;
 149   struct list_head node;
 150 };
 151
 152 struct vhost_dev {
 153         struct mm_struct *mm;
 154         struct mutex mutex;
 155         struct vhost_virtqueue **vqs;
 156         int nvqs;
 157         struct file *log_file;
 158         struct eventfd_ctx *log_ctx;
 159         struct llist_head work_list;
 160         struct task_struct *worker;
 161         struct vhost_umem *umem;
 162         struct vhost_umem *iotlb;
 163         spinlock_t iotlb_lock;
 164         struct list_head read_list;
 165         struct list_head pending_list;
 166         wait_queue_head_t wait;
 167 };
 168
 169 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
 170 long vhost_dev_set_owner(struct vhost_dev *dev);
 171 bool vhost_dev_has_owner(struct vhost_dev *dev);
 172 long vhost_dev_check_owner(struct vhost_dev *);
 173 struct vhost_umem *vhost_dev_reset_owner_prepare(void);
 174 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_umem *);
 175 void vhost_dev_cleanup(struct vhost_dev *, bool locked);
 176 void vhost_dev_stop(struct vhost_dev *);
 177 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
 178 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
 179 int vhost_vq_access_ok(struct vhost_virtqueue *vq);
 180 int vhost_log_access_ok(struct vhost_dev *);
 181
 182 int vhost_get_vq_desc(struct vhost_virtqueue *,
 183                       struct iovec iov[], unsigned int iov_count,
 184                       unsigned int *out_num, unsigned int *in_num,
 185                       struct vhost_log *log, unsigned int *log_num);
 186 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 187
 188 int vhost_vq_init_access(struct vhost_virtqueue *);
 189 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 190 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 191                      unsigned count);
 192 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 193                                unsigned int id, int len);
 194 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 195                                struct vring_used_elem *heads, unsigned count);
 196 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 197 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 198 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
 199 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 200
 201 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 202                     unsigned int log_num, u64 len);
 203 int vq_iotlb_prefetch(struct vhost_virtqueue *vq);
 204
 205 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
 206 void vhost_enqueue_msg(struct vhost_dev *dev,
 207                        struct list_head *head,
 208                        struct vhost_msg_node *node);
 209 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
 210                                          struct list_head *head);
 211 unsigned int vhost_chr_poll(struct file *file, struct vhost_dev *dev,
 212                             poll_table *wait);
 213 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
 214                             int noblock);
 215 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
 216                              struct iov_iter *from);
 217 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
 218
 219 #define vq_err(vq, fmt, ...) do {                                  \
 220                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 221                 if ((vq)->error_ctx)                               \
 222                                 eventfd_signal((vq)->error_ctx, 1);\
 223         } while (0)
 224
 225 enum {
 226         VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 227                          (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 228                          (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 229                          (1ULL << VHOST_F_LOG_ALL) |
 230                          (1ULL << VIRTIO_F_ANY_LAYOUT) |
 231                          (1ULL << VIRTIO_F_VERSION_1)
 232 };
 233
 234 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
 235 {
 236         return vq->acked_features & (1ULL << bit);
 237 }
 238
 239 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 240 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 241 {
 242         return vq->is_le;
 243 }
 244 #else
 245 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 246 {
 247         return virtio_legacy_is_little_endian() || vq->is_le;
 248 }
 249 #endif
 250
 251 /* Memory accessors */
 252 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
 253 {
 254         return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
 255 }
 256
 257 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
 258 {
 259         return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
 260 }
 261
 262 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
 263 {
 264         return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
 265 }
 266
 267 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
 268 {
 269         return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
 270 }
 271
 272 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
 273 {
 274         return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
 275 }
 276
 277 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
 278 {
 279         return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
 280 }
 281 #endif