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 <linux/atomic.h>
  15
  16/* This is for zerocopy, used buffer len is set to 1 when lower device DMA
  17 * done */
  18#define VHOST_DMA_DONE_LEN      1
  19#define VHOST_DMA_CLEAR_LEN     0
  20
  21struct vhost_device;
  22
  23struct vhost_work;
  24typedef void (*vhost_work_fn_t)(struct vhost_work *work);
  25
  26struct 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. */
  37struct 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
  46void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
  47                     unsigned long mask, struct vhost_dev *dev);
  48void vhost_poll_start(struct vhost_poll *poll, struct file *file);
  49void vhost_poll_stop(struct vhost_poll *poll);
  50void vhost_poll_flush(struct vhost_poll *poll);
  51void vhost_poll_queue(struct vhost_poll *poll);
  52
  53struct vhost_log {
  54        u64 addr;
  55        u64 len;
  56};
  57
  58struct vhost_virtqueue;
  59
  60struct vhost_ubuf_ref {
  61        struct kref kref;
  62        wait_queue_head_t wait;
  63        struct vhost_virtqueue *vq;
  64};
  65
  66struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *, bool zcopy);
  67void vhost_ubuf_put(struct vhost_ubuf_ref *);
  68void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *);
  69
  70/* The virtqueue structure describes a queue attached to a device. */
  71struct vhost_virtqueue {
  72        struct vhost_dev *dev;
  73
  74        /* The actual ring of buffers. */
  75        struct mutex mutex;
  76        unsigned int num;
  77        struct vring_desc __user *desc;
  78        struct vring_avail __user *avail;
  79        struct vring_used __user *used;
  80        struct file *kick;
  81        struct file *call;
  82        struct file *error;
  83        struct eventfd_ctx *call_ctx;
  84        struct eventfd_ctx *error_ctx;
  85        struct eventfd_ctx *log_ctx;
  86
  87        struct vhost_poll poll;
  88
  89        /* The routine to call when the Guest pings us, or timeout. */
  90        vhost_work_fn_t handle_kick;
  91
  92        /* Last available index we saw. */
  93        u16 last_avail_idx;
  94
  95        /* Caches available index value from user. */
  96        u16 avail_idx;
  97
  98        /* Last index we used. */
  99        u16 last_used_idx;
 100
 101        /* Used flags */
 102        u16 used_flags;
 103
 104        /* Last used index value we have signalled on */
 105        u16 signalled_used;
 106
 107        /* Last used index value we have signalled on */
 108        bool signalled_used_valid;
 109
 110        /* Log writes to used structure. */
 111        bool log_used;
 112        u64 log_addr;
 113
 114        struct iovec iov[UIO_MAXIOV];
 115        /* hdr is used to store the virtio header.
 116         * Since each iovec has >= 1 byte length, we never need more than
 117         * header length entries to store the header. */
 118        struct iovec hdr[sizeof(struct virtio_net_hdr_mrg_rxbuf)];
 119        struct iovec *indirect;
 120        size_t vhost_hlen;
 121        size_t sock_hlen;
 122        struct vring_used_elem *heads;
 123        /* We use a kind of RCU to access private pointer.
 124         * All readers access it from worker, which makes it possible to
 125         * flush the vhost_work instead of synchronize_rcu. Therefore readers do
 126         * not need to call rcu_read_lock/rcu_read_unlock: the beginning of
 127         * vhost_work execution acts instead of rcu_read_lock() and the end of
 128         * vhost_work execution acts instead of rcu_read_unlock().
 129         * Writers use virtqueue mutex. */
 130        void __rcu *private_data;
 131        /* Log write descriptors */
 132        void __user *log_base;
 133        struct vhost_log *log;
 134        /* vhost zerocopy support fields below: */
 135        /* last used idx for outstanding DMA zerocopy buffers */
 136        int upend_idx;
 137        /* first used idx for DMA done zerocopy buffers */
 138        int done_idx;
 139        /* an array of userspace buffers info */
 140        struct ubuf_info *ubuf_info;
 141        /* Reference counting for outstanding ubufs.
 142         * Protected by vq mutex. Writers must also take device mutex. */
 143        struct vhost_ubuf_ref *ubufs;
 144};
 145
 146struct vhost_dev {
 147        /* Readers use RCU to access memory table pointer
 148         * log base pointer and features.
 149         * Writers use mutex below.*/
 150        struct vhost_memory __rcu *memory;
 151        struct mm_struct *mm;
 152        struct mutex mutex;
 153        unsigned acked_features;
 154        struct vhost_virtqueue *vqs;
 155        int nvqs;
 156        struct file *log_file;
 157        struct eventfd_ctx *log_ctx;
 158        spinlock_t work_lock;
 159        struct list_head work_list;
 160        struct task_struct *worker;
 161};
 162
 163long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
 164long vhost_dev_check_owner(struct vhost_dev *);
 165long vhost_dev_reset_owner(struct vhost_dev *);
 166void vhost_dev_cleanup(struct vhost_dev *);
 167long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
 168int vhost_vq_access_ok(struct vhost_virtqueue *vq);
 169int vhost_log_access_ok(struct vhost_dev *);
 170
 171int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
 172                      struct iovec iov[], unsigned int iov_count,
 173                      unsigned int *out_num, unsigned int *in_num,
 174                      struct vhost_log *log, unsigned int *log_num);
 175void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 176
 177int vhost_init_used(struct vhost_virtqueue *);
 178int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 179int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 180                     unsigned count);
 181void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 182                               unsigned int id, int len);
 183void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 184                               struct vring_used_elem *heads, unsigned count);
 185void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 186void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 187bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 188
 189int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 190                    unsigned int log_num, u64 len);
 191void vhost_zerocopy_callback(void *arg);
 192int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq);
 193
 194#define vq_err(vq, fmt, ...) do {                                  \
 195                pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 196                if ((vq)->error_ctx)                               \
 197                                eventfd_signal((vq)->error_ctx, 1);\
 198        } while (0)
 199
 200enum {
 201        VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 202                         (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 203                         (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 204                         (1ULL << VHOST_F_LOG_ALL) |
 205                         (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
 206                         (1ULL << VIRTIO_NET_F_MRG_RXBUF),
 207};
 208
 209static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
 210{
 211        unsigned acked_features;
 212
 213        /* TODO: check that we are running from vhost_worker or dev mutex is
 214         * held? */
 215        acked_features = rcu_dereference_index_check(dev->acked_features, 1);
 216        return acked_features & (1 << bit);
 217}
 218
 219void vhost_enable_zcopy(int vq);
 220
 221#endif
 222