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/workqueue.h>
   9 #include <linux/poll.h>
  10 #include <linux/file.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/uio.h>
  13 #include <linux/virtio_config.h>
  14 #include <linux/virtio_ring.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 /* Poll a file (eventfd or socket) */
  24 /* Note: there's nothing vhost specific about this structure. */
  25 struct vhost_poll {
  26         poll_table                table;
  27         wait_queue_head_t        *wqh;
  28         wait_queue_t              wait;
  29         /* struct which will handle all actual work. */
  30         struct work_struct        work;
  31         unsigned long             mask;
  32 };
  33
  34 void vhost_poll_init(struct vhost_poll *poll, work_func_t func,
  35                      unsigned long mask);
  36 void vhost_poll_start(struct vhost_poll *poll, struct file *file);
  37 void vhost_poll_stop(struct vhost_poll *poll);
  38 void vhost_poll_flush(struct vhost_poll *poll);
  39 void vhost_poll_queue(struct vhost_poll *poll);
  40
  41 struct vhost_log {
  42         u64 addr;
  43         u64 len;
  44 };
  45
  46 /* The virtqueue structure describes a queue attached to a device. */
  47 struct vhost_virtqueue {
  48         struct vhost_dev *dev;
  49
  50         /* The actual ring of buffers. */
  51         struct mutex mutex;
  52         unsigned int num;
  53         struct vring_desc __user *desc;
  54         struct vring_avail __user *avail;
  55         struct vring_used __user *used;
  56         struct file *kick;
  57         struct file *call;
  58         struct file *error;
  59         struct eventfd_ctx *call_ctx;
  60         struct eventfd_ctx *error_ctx;
  61         struct eventfd_ctx *log_ctx;
  62
  63         struct vhost_poll poll;
  64
  65         /* The routine to call when the Guest pings us, or timeout. */
  66         work_func_t handle_kick;
  67
  68         /* Last available index we saw. */
  69         u16 last_avail_idx;
  70
  71         /* Caches available index value from user. */
  72         u16 avail_idx;
  73
  74         /* Last index we used. */
  75         u16 last_used_idx;
  76
  77         /* Used flags */
  78         u16 used_flags;
  79
  80         /* Log writes to used structure. */
  81         bool log_used;
  82         u64 log_addr;
  83
  84         struct iovec indirect[VHOST_NET_MAX_SG];
  85         struct iovec iov[VHOST_NET_MAX_SG];
  86         struct iovec hdr[VHOST_NET_MAX_SG];
  87         size_t hdr_size;
  88         /* We use a kind of RCU to access private pointer.
  89          * All readers access it from workqueue, which makes it possible to
  90          * flush the workqueue instead of synchronize_rcu. Therefore readers do
  91          * not need to call rcu_read_lock/rcu_read_unlock: the beginning of
  92          * work item execution acts instead of rcu_read_lock() and the end of
  93          * work item execution acts instead of rcu_read_lock().
  94          * Writers use virtqueue mutex. */
  95         void *private_data;
  96         /* Log write descriptors */
  97         void __user *log_base;
  98         struct vhost_log log[VHOST_NET_MAX_SG];
  99 };
 100
 101 struct vhost_dev {
 102         /* Readers use RCU to access memory table pointer
 103          * log base pointer and features.
 104          * Writers use mutex below.*/
 105         struct vhost_memory *memory;
 106         struct mm_struct *mm;
 107         struct mutex mutex;
 108         unsigned acked_features;
 109         struct vhost_virtqueue *vqs;
 110         int nvqs;
 111         struct file *log_file;
 112         struct eventfd_ctx *log_ctx;
 113 };
 114
 115 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
 116 long vhost_dev_check_owner(struct vhost_dev *);
 117 long vhost_dev_reset_owner(struct vhost_dev *);
 118 void vhost_dev_cleanup(struct vhost_dev *);
 119 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
 120 int vhost_vq_access_ok(struct vhost_virtqueue *vq);
 121 int vhost_log_access_ok(struct vhost_dev *);
 122
 123 unsigned vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
 124                            struct iovec iov[], unsigned int iov_count,
 125                            unsigned int *out_num, unsigned int *in_num,
 126                            struct vhost_log *log, unsigned int *log_num);
 127 void vhost_discard_vq_desc(struct vhost_virtqueue *);
 128
 129 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 130 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 131 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 132                                unsigned int head, int len);
 133 void vhost_disable_notify(struct vhost_virtqueue *);
 134 bool vhost_enable_notify(struct vhost_virtqueue *);
 135
 136 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 137                     unsigned int log_num, u64 len);
 138
 139 int vhost_init(void);
 140 void vhost_cleanup(void);
 141
 142 #define vq_err(vq, fmt, ...) do {                                  \
 143                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 144                 if ((vq)->error_ctx)                               \
 145                                 eventfd_signal((vq)->error_ctx, 1);\
 146         } while (0)
 147
 148 enum {
 149         VHOST_FEATURES = (1 << VIRTIO_F_NOTIFY_ON_EMPTY) |
 150                          (1 << VIRTIO_RING_F_INDIRECT_DESC) |
 151                          (1 << VHOST_F_LOG_ALL) |
 152                          (1 << VHOST_NET_F_VIRTIO_NET_HDR),
 153 };
 154
 155 static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
 156 {
 157         unsigned acked_features = rcu_dereference(dev->acked_features);
 158         return acked_features & (1 << bit);
 159 }
 160
 161 #endif