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/skbuff.h>
  11 #include <linux/uio.h>
  12 #include <linux/virtio_config.h>
  13 #include <linux/virtio_ring.h>
  14 #include <asm/atomic.h>
  15
  16 struct vhost_device;
  17
  18 enum {
  19         /* Enough place for all fragments, head, and virtio net header. */
  20         VHOST_NET_MAX_SG = MAX_SKB_FRAGS + 2,
  21 };
  22
  23 struct vhost_work;
  24 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
  25
  26 struct vhost_work {
  27         struct list_head          node;
  28         vhost_work_fn_t           fn;
  29         wait_queue_head_t         done;
  30         int                       flushing;
  31         unsigned                  queue_seq;
  32         unsigned                  done_seq;
  33 };
  34
  35 /* Poll a file (eventfd or socket) */
  36 /* Note: there's nothing vhost specific about this structure. */
  37 struct vhost_poll {
  38         poll_table                table;
  39         wait_queue_head_t        *wqh;
  40         wait_queue_t              wait;
  41         struct vhost_work         work;
  42         unsigned long             mask;
  43         struct vhost_dev         *dev;
  44 };
  45
  46 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
  47                      unsigned long mask, struct vhost_dev *dev);
  48 void vhost_poll_start(struct vhost_poll *poll, struct file *file);
  49 void vhost_poll_stop(struct vhost_poll *poll);
  50 void vhost_poll_flush(struct vhost_poll *poll);
  51 void vhost_poll_queue(struct vhost_poll *poll);
  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         /* Log writes to used structure. */
  93         bool log_used;
  94         u64 log_addr;
  95
  96         struct iovec indirect[VHOST_NET_MAX_SG];
  97         struct iovec iov[VHOST_NET_MAX_SG];
  98         struct iovec hdr[VHOST_NET_MAX_SG];
  99         size_t vhost_hlen;
 100         size_t sock_hlen;
 101         struct vring_used_elem heads[VHOST_NET_MAX_SG];
 102         /* We use a kind of RCU to access private pointer.
 103          * All readers access it from worker, which makes it possible to
 104          * flush the vhost_work instead of synchronize_rcu. Therefore readers do
 105          * not need to call rcu_read_lock/rcu_read_unlock: the beginning of
 106          * vhost_work execution acts instead of rcu_read_lock() and the end of
 107          * vhost_work execution acts instead of rcu_read_lock().
 108          * Writers use virtqueue mutex. */
 109         void *private_data;
 110         /* Log write descriptors */
 111         void __user *log_base;
 112         struct vhost_log log[VHOST_NET_MAX_SG];
 113 };
 114
 115 struct vhost_dev {
 116         /* Readers use RCU to access memory table pointer
 117          * log base pointer and features.
 118          * Writers use mutex below.*/
 119         struct vhost_memory *memory;
 120         struct mm_struct *mm;
 121         struct mutex mutex;
 122         unsigned acked_features;
 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 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
 133 long vhost_dev_check_owner(struct vhost_dev *);
 134 long vhost_dev_reset_owner(struct vhost_dev *);
 135 void vhost_dev_cleanup(struct vhost_dev *);
 136 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
 137 int vhost_vq_access_ok(struct vhost_virtqueue *vq);
 138 int vhost_log_access_ok(struct vhost_dev *);
 139
 140 int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
 141                       struct iovec iov[], unsigned int iov_count,
 142                       unsigned int *out_num, unsigned int *in_num,
 143                       struct vhost_log *log, unsigned int *log_num);
 144 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 145
 146 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 147 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 148                      unsigned count);
 149 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 150                                unsigned int id, int len);
 151 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 152                                struct vring_used_elem *heads, unsigned count);
 153 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 154 void vhost_disable_notify(struct vhost_virtqueue *);
 155 bool vhost_enable_notify(struct vhost_virtqueue *);
 156
 157 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 158                     unsigned int log_num, u64 len);
 159
 160 #define vq_err(vq, fmt, ...) do {                                  \
 161                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 162                 if ((vq)->error_ctx)                               \
 163                                 eventfd_signal((vq)->error_ctx, 1);\
 164         } while (0)
 165
 166 enum {
 167         VHOST_FEATURES = (1 << VIRTIO_F_NOTIFY_ON_EMPTY) |
 168                          (1 << VIRTIO_RING_F_INDIRECT_DESC) |
 169                          (1 << VHOST_F_LOG_ALL) |
 170                          (1 << VHOST_NET_F_VIRTIO_NET_HDR) |
 171                          (1 << VIRTIO_NET_F_MRG_RXBUF),
 172 };
 173
 174 static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
 175 {
 176         unsigned acked_features = rcu_dereference(dev->acked_features);
 177         return acked_features & (1 << bit);
 178 }
 179
 180 #endif