blob: a801e2821d0387e2fc825e4a124bf2413f16d181 [file] [log] [blame]
#ifndef _VHOST_H
#define _VHOST_H
#include <linux/eventfd.h>
#include <linux/vhost.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/file.h>
#include <linux/skbuff.h>
#include <linux/uio.h>
#include <linux/virtio_config.h>
#include <linux/virtio_ring.h>
#include <linux/atomic.h>
/* This is for zerocopy, used buffer len is set to 1 when lower device DMA
* done */
struct vhost_device;
struct vhost_work;
typedef void (*vhost_work_fn_t)(struct vhost_work *work);
struct vhost_work {
struct list_head node;
vhost_work_fn_t fn;
wait_queue_head_t done;
int flushing;
unsigned queue_seq;
unsigned done_seq;
/* Poll a file (eventfd or socket) */
/* Note: there's nothing vhost specific about this structure. */
struct vhost_poll {
poll_table table;
wait_queue_head_t *wqh;
wait_queue_t wait;
struct vhost_work work;
unsigned long mask;
struct vhost_dev *dev;
void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
unsigned long mask, struct vhost_dev *dev);
void vhost_poll_start(struct vhost_poll *poll, struct file *file);
void vhost_poll_stop(struct vhost_poll *poll);
void vhost_poll_flush(struct vhost_poll *poll);
void vhost_poll_queue(struct vhost_poll *poll);
struct vhost_log {
u64 addr;
u64 len;
struct vhost_virtqueue;
struct vhost_ubuf_ref {
struct kref kref;
wait_queue_head_t wait;
struct vhost_virtqueue *vq;
struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *, bool zcopy);
void vhost_ubuf_put(struct vhost_ubuf_ref *);
void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *);
/* The virtqueue structure describes a queue attached to a device. */
struct vhost_virtqueue {
struct vhost_dev *dev;
/* The actual ring of buffers. */
struct mutex mutex;
unsigned int num;
struct vring_desc __user *desc;
struct vring_avail __user *avail;
struct vring_used __user *used;
struct file *kick;
struct file *call;
struct file *error;
struct eventfd_ctx *call_ctx;
struct eventfd_ctx *error_ctx;
struct eventfd_ctx *log_ctx;
struct vhost_poll poll;
/* The routine to call when the Guest pings us, or timeout. */
vhost_work_fn_t handle_kick;
/* Last available index we saw. */
u16 last_avail_idx;
/* Caches available index value from user. */
u16 avail_idx;
/* Last index we used. */
u16 last_used_idx;
/* Used flags */
u16 used_flags;
/* Last used index value we have signalled on */
u16 signalled_used;
/* Last used index value we have signalled on */
bool signalled_used_valid;
/* Log writes to used structure. */
bool log_used;
u64 log_addr;
struct iovec iov[UIO_MAXIOV];
/* hdr is used to store the virtio header.
* Since each iovec has >= 1 byte length, we never need more than
* header length entries to store the header. */
struct iovec hdr[sizeof(struct virtio_net_hdr_mrg_rxbuf)];
struct iovec *indirect;
size_t vhost_hlen;
size_t sock_hlen;
struct vring_used_elem *heads;
/* We use a kind of RCU to access private pointer.
* All readers access it from worker, which makes it possible to
* flush the vhost_work instead of synchronize_rcu. Therefore readers do
* not need to call rcu_read_lock/rcu_read_unlock: the beginning of
* vhost_work execution acts instead of rcu_read_lock() and the end of
* vhost_work execution acts instead of rcu_read_unlock().
* Writers use virtqueue mutex. */
void __rcu *private_data;
/* Log write descriptors */
void __user *log_base;
struct vhost_log *log;
/* vhost zerocopy support fields below: */
/* last used idx for outstanding DMA zerocopy buffers */
int upend_idx;
/* first used idx for DMA done zerocopy buffers */
int done_idx;
/* an array of userspace buffers info */
struct ubuf_info *ubuf_info;
/* Reference counting for outstanding ubufs.
* Protected by vq mutex. Writers must also take device mutex. */
struct vhost_ubuf_ref *ubufs;
struct vhost_dev {
/* Readers use RCU to access memory table pointer
* log base pointer and features.
* Writers use mutex below.*/
struct vhost_memory __rcu *memory;
struct mm_struct *mm;
struct mutex mutex;
unsigned acked_features;
struct vhost_virtqueue *vqs;
int nvqs;
struct file *log_file;
struct eventfd_ctx *log_ctx;
spinlock_t work_lock;
struct list_head work_list;
struct task_struct *worker;
long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
long vhost_dev_check_owner(struct vhost_dev *);
long vhost_dev_reset_owner(struct vhost_dev *);
void vhost_dev_cleanup(struct vhost_dev *);
long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
int vhost_vq_access_ok(struct vhost_virtqueue *vq);
int vhost_log_access_ok(struct vhost_dev *);
int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
struct iovec iov[], unsigned int iov_count,
unsigned int *out_num, unsigned int *in_num,
struct vhost_log *log, unsigned int *log_num);
void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
int vhost_init_used(struct vhost_virtqueue *);
int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
unsigned count);
void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
unsigned int id, int len);
void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
struct vring_used_elem *heads, unsigned count);
void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
unsigned int log_num, u64 len);
void vhost_zerocopy_callback(void *arg);
int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq);
#define vq_err(vq, fmt, ...) do { \
pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
if ((vq)->error_ctx) \
eventfd_signal((vq)->error_ctx, 1);\
} while (0)
enum {
static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
unsigned acked_features;
/* TODO: check that we are running from vhost_worker or dev mutex is
* held? */
acked_features = rcu_dereference_index_check(dev->acked_features, 1);
return acked_features & (1 << bit);
void vhost_enable_zcopy(int vq);