LXR linux/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
  16struct vhost_device;
  17
  18struct vhost_work;
  19typedef void (*vhost_work_fn_t)(struct vhost_work *work);
  20
  21struct vhost_work {
  22        struct list_head          node;
  23        vhost_work_fn_t           fn;
  24        wait_queue_head_t         done;
  25        int                       flushing;
  26        unsigned                  queue_seq;
  27        unsigned                  done_seq;
  28};
  29
  30/* Poll a file (eventfd or socket) */
  31/* Note: there's nothing vhost specific about this structure. */
  32struct vhost_poll {
  33        poll_table                table;
  34        wait_queue_head_t        *wqh;
  35        wait_queue_t              wait;
  36        struct vhost_work         work;
  37        unsigned long             mask;
  38        struct vhost_dev         *dev;
  39};
  40
  41void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
  42                     unsigned long mask, struct vhost_dev *dev);
  43void vhost_poll_start(struct vhost_poll *poll, struct file *file);
  44void vhost_poll_stop(struct vhost_poll *poll);
  45void vhost_poll_flush(struct vhost_poll *poll);
  46void vhost_poll_queue(struct vhost_poll *poll);
  47
  48struct vhost_log {
  49        u64 addr;
  50        u64 len;
  51};
  52
  53/* The virtqueue structure describes a queue attached to a device. */
  54struct vhost_virtqueue {
  55        struct vhost_dev *dev;
  56
  57        /* The actual ring of buffers. */
  58        struct mutex mutex;
  59        unsigned int num;
  60        struct vring_desc __user *desc;
  61        struct vring_avail __user *avail;
  62        struct vring_used __user *used;
  63        struct file *kick;
  64        struct file *call;
  65        struct file *error;
  66        struct eventfd_ctx *call_ctx;
  67        struct eventfd_ctx *error_ctx;
  68        struct eventfd_ctx *log_ctx;
  69
  70        struct vhost_poll poll;
  71
  72        /* The routine to call when the Guest pings us, or timeout. */
  73        vhost_work_fn_t handle_kick;
  74
  75        /* Last available index we saw. */
  76        u16 last_avail_idx;
  77
  78        /* Caches available index value from user. */
  79        u16 avail_idx;
  80
  81        /* Last index we used. */
  82        u16 last_used_idx;
  83
  84        /* Used flags */
  85        u16 used_flags;
  86
  87        /* Log writes to used structure. */
  88        bool log_used;
  89        u64 log_addr;
  90
  91        struct iovec iov[UIO_MAXIOV];
  92        /* hdr is used to store the virtio header.
  93         * Since each iovec has >= 1 byte length, we never need more than
  94         * header length entries to store the header. */
  95        struct iovec hdr[sizeof(struct virtio_net_hdr_mrg_rxbuf)];
  96        struct iovec *indirect;
  97        size_t vhost_hlen;
  98        size_t sock_hlen;
  99        struct vring_used_elem *heads;
 100        /* We use a kind of RCU to access private pointer.
 101         * All readers access it from worker, which makes it possible to
 102         * flush the vhost_work instead of synchronize_rcu. Therefore readers do
 103         * not need to call rcu_read_lock/rcu_read_unlock: the beginning of
 104         * vhost_work execution acts instead of rcu_read_lock() and the end of
 105         * vhost_work execution acts instead of rcu_read_unlock().
 106         * Writers use virtqueue mutex. */
 107        void __rcu *private_data;
 108        /* Log write descriptors */
 109        void __user *log_base;
 110        struct vhost_log *log;
 111};
 112
 113struct vhost_dev {
 114        /* Readers use RCU to access memory table pointer
 115         * log base pointer and features.
 116         * Writers use mutex below.*/
 117        struct vhost_memory __rcu *memory;
 118        struct mm_struct *mm;
 119        struct mutex mutex;
 120        unsigned acked_features;
 121        struct vhost_virtqueue *vqs;
 122        int nvqs;
 123        struct file *log_file;
 124        struct eventfd_ctx *log_ctx;
 125        spinlock_t work_lock;
 126        struct list_head work_list;
 127        struct task_struct *worker;
 128};
 129
 130long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
 131long vhost_dev_check_owner(struct vhost_dev *);
 132long vhost_dev_reset_owner(struct vhost_dev *);
 133void vhost_dev_cleanup(struct vhost_dev *);
 134long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
 135int vhost_vq_access_ok(struct vhost_virtqueue *vq);
 136int vhost_log_access_ok(struct vhost_dev *);
 137
 138int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
 139                      struct iovec iov[], unsigned int iov_count,
 140                      unsigned int *out_num, unsigned int *in_num,
 141                      struct vhost_log *log, unsigned int *log_num);
 142void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 143
 144int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 145int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 146                     unsigned count);
 147void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 148                               unsigned int id, int len);
 149void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 150                               struct vring_used_elem *heads, unsigned count);
 151void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 152void vhost_disable_notify(struct vhost_virtqueue *);
 153bool vhost_enable_notify(struct vhost_virtqueue *);
 154
 155int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 156                    unsigned int log_num, u64 len);
 157
 158#define vq_err(vq, fmt, ...) do {                                  \
 159                pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 160                if ((vq)->error_ctx)                               \
 161                                eventfd_signal((vq)->error_ctx, 1);\
 162        } while (0)
 163
 164enum {
 165        VHOST_FEATURES = (1 << VIRTIO_F_NOTIFY_ON_EMPTY) |
 166                         (1 << VIRTIO_RING_F_INDIRECT_DESC) |
 167                         (1 << VHOST_F_LOG_ALL) |
 168                         (1 << VHOST_NET_F_VIRTIO_NET_HDR) |
 169                         (1 << VIRTIO_NET_F_MRG_RXBUF),
 170};
 171
 172static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
 173{
 174        unsigned acked_features;
 175
 176        /* TODO: check that we are running from vhost_worker or dev mutex is
 177         * held? */
 178        acked_features = rcu_dereference_index_check(dev->acked_features, 1);
 179        return acked_features & (1 << bit);
 180}
 181
 182#endif
 183