vhost.h revision 22fa90c7fb479694d6affebc049d21f06b714be6 
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/uio.h>
11#include <linux/virtio_config.h>
12#include <linux/virtio_ring.h>
13#include <linux/atomic.h>
14
15struct vhost_device;
16
17struct vhost_work;
18typedef void (*vhost_work_fn_t)(struct vhost_work *work);
19
20struct vhost_work {
21	struct list_head	  node;
22	vhost_work_fn_t		  fn;
23	wait_queue_head_t	  done;
24	int			  flushing;
25	unsigned		  queue_seq;
26	unsigned		  done_seq;
27};
28
29/* Poll a file (eventfd or socket) */
30/* Note: there's nothing vhost specific about this structure. */
31struct vhost_poll {
32	poll_table                table;
33	wait_queue_head_t        *wqh;
34	wait_queue_t              wait;
35	struct vhost_work	  work;
36	unsigned long		  mask;
37	struct vhost_dev	 *dev;
38};
39
40void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
41void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
42
43void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
44		     unsigned long mask, struct vhost_dev *dev);
45int vhost_poll_start(struct vhost_poll *poll, struct file *file);
46void vhost_poll_stop(struct vhost_poll *poll);
47void vhost_poll_flush(struct vhost_poll *poll);
48void vhost_poll_queue(struct vhost_poll *poll);
49void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work);
50long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
51
52struct vhost_log {
53	u64 addr;
54	u64 len;
55};
56
57struct vhost_virtqueue;
58
59/* The virtqueue structure describes a queue attached to a device. */
60struct vhost_virtqueue {
61	struct vhost_dev *dev;
62
63	/* The actual ring of buffers. */
64	struct mutex mutex;
65	unsigned int num;
66	struct vring_desc __user *desc;
67	struct vring_avail __user *avail;
68	struct vring_used __user *used;
69	struct file *kick;
70	struct file *call;
71	struct file *error;
72	struct eventfd_ctx *call_ctx;
73	struct eventfd_ctx *error_ctx;
74	struct eventfd_ctx *log_ctx;
75
76	struct vhost_poll poll;
77
78	/* The routine to call when the Guest pings us, or timeout. */
79	vhost_work_fn_t handle_kick;
80
81	/* Last available index we saw. */
82	u16 last_avail_idx;
83
84	/* Caches available index value from user. */
85	u16 avail_idx;
86
87	/* Last index we used. */
88	u16 last_used_idx;
89
90	/* Used flags */
91	u16 used_flags;
92
93	/* Last used index value we have signalled on */
94	u16 signalled_used;
95
96	/* Last used index value we have signalled on */
97	bool signalled_used_valid;
98
99	/* Log writes to used structure. */
100	bool log_used;
101	u64 log_addr;
102
103	struct iovec iov[UIO_MAXIOV];
104	struct iovec *indirect;
105	struct vring_used_elem *heads;
106	/* Protected by virtqueue mutex. */
107	void *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_set_owner(struct vhost_dev *dev);
132bool vhost_dev_has_owner(struct vhost_dev *dev);
133long vhost_dev_check_owner(struct vhost_dev *);
134struct vhost_memory *vhost_dev_reset_owner_prepare(void);
135void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_memory *);
136void vhost_dev_cleanup(struct vhost_dev *, bool locked);
137void vhost_dev_stop(struct vhost_dev *);
138long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
139long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
140int vhost_vq_access_ok(struct vhost_virtqueue *vq);
141int vhost_log_access_ok(struct vhost_dev *);
142
143int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
144		      struct iovec iov[], unsigned int iov_count,
145		      unsigned int *out_num, unsigned int *in_num,
146		      struct vhost_log *log, unsigned int *log_num);
147void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
148
149int vhost_init_used(struct vhost_virtqueue *);
150int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
151int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
152		     unsigned count);
153void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
154			       unsigned int id, int len);
155void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
156			       struct vring_used_elem *heads, unsigned count);
157void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
158void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
159bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
160
161int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
162		    unsigned int log_num, u64 len);
163
164#define vq_err(vq, fmt, ...) do {                                  \
165		pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
166		if ((vq)->error_ctx)                               \
167				eventfd_signal((vq)->error_ctx, 1);\
168	} while (0)
169
170enum {
171	VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
172			 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
173			 (1ULL << VIRTIO_RING_F_EVENT_IDX) |
174			 (1ULL << VHOST_F_LOG_ALL),
175};
176
177static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
178{
179	unsigned acked_features;
180
181	/* TODO: check that we are running from vhost_worker or dev mutex is
182	 * held? */
183	acked_features = rcu_dereference_index_check(dev->acked_features, 1);
184	return acked_features & (1 << bit);
185}
186#endif
187