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
15 struct vhost_device;
16
17 struct vhost_work;
18 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
19
20 struct 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. */
31 struct 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
40 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
41 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
42
43 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
44 unsigned long mask, struct vhost_dev *dev);
45 int vhost_poll_start(struct vhost_poll *poll, struct file *file);
46 void vhost_poll_stop(struct vhost_poll *poll);
47 void vhost_poll_flush(struct vhost_poll *poll);
48 void vhost_poll_queue(struct vhost_poll *poll);
49
50 struct vhost_log {
51 u64 addr;
52 u64 len;
53 };
54
55 struct vhost_virtqueue;
56
57 /* The virtqueue structure describes a queue attached to a device. */
58 struct vhost_virtqueue {
59 struct vhost_dev *dev;
60
61 /* The actual ring of buffers. */
62 struct mutex mutex;
63 unsigned int num;
64 struct vring_desc __user *desc;
65 struct vring_avail __user *avail;
66 struct vring_used __user *used;
67 struct file *kick;
68 struct file *call;
69 struct file *error;
70 struct eventfd_ctx *call_ctx;
71 struct eventfd_ctx *error_ctx;
72 struct eventfd_ctx *log_ctx;
73
74 struct vhost_poll poll;
75
76 /* The routine to call when the Guest pings us, or timeout. */
77 vhost_work_fn_t handle_kick;
78
79 /* Last available index we saw. */
80 u16 last_avail_idx;
81
82 /* Caches available index value from user. */
83 u16 avail_idx;
84
85 /* Last index we used. */
86 u16 last_used_idx;
87
88 /* Used flags */
89 u16 used_flags;
90
91 /* Last used index value we have signalled on */
92 u16 signalled_used;
93
94 /* Last used index value we have signalled on */
95 bool signalled_used_valid;
96
97 /* Log writes to used structure. */
98 bool log_used;
99 u64 log_addr;
100
101 struct iovec iov[UIO_MAXIOV];
102 struct iovec *indirect;
103 struct vring_used_elem *heads;
104 /* We use a kind of RCU to access private pointer.
105 * All readers access it from worker, which makes it possible to
106 * flush the vhost_work instead of synchronize_rcu. Therefore readers do
107 * not need to call rcu_read_lock/rcu_read_unlock: the beginning of
108 * vhost_work execution acts instead of rcu_read_lock() and the end of
109 * vhost_work execution acts instead of rcu_read_unlock().
110 * Writers use virtqueue mutex. */
111 void __rcu *private_data;
112 /* Log write descriptors */
113 void __user *log_base;
114 struct vhost_log *log;
115 };
116
117 struct vhost_dev {
118 /* Readers use RCU to access memory table pointer
119 * log base pointer and features.
120 * Writers use mutex below.*/
121 struct vhost_memory __rcu *memory;
122 struct mm_struct *mm;
123 struct mutex mutex;
124 unsigned acked_features;
125 struct vhost_virtqueue **vqs;
126 int nvqs;
127 struct file *log_file;
128 struct eventfd_ctx *log_ctx;
129 spinlock_t work_lock;
130 struct list_head work_list;
131 struct task_struct *worker;
132 };
133
134 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
135 long vhost_dev_set_owner(struct vhost_dev *dev);
136 bool vhost_dev_has_owner(struct vhost_dev *dev);
137 long vhost_dev_check_owner(struct vhost_dev *);
138 struct vhost_memory *vhost_dev_reset_owner_prepare(void);
139 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_memory *);
140 void vhost_dev_cleanup(struct vhost_dev *, bool locked);
141 void vhost_dev_stop(struct vhost_dev *);
142 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
143 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
144 int vhost_vq_access_ok(struct vhost_virtqueue *vq);
145 int vhost_log_access_ok(struct vhost_dev *);
146
147 int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *,
148 struct iovec iov[], unsigned int iov_count,
149 unsigned int *out_num, unsigned int *in_num,
150 struct vhost_log *log, unsigned int *log_num);
151 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
152
153 int vhost_init_used(struct vhost_virtqueue *);
154 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
155 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
156 unsigned count);
157 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
158 unsigned int id, int len);
159 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
160 struct vring_used_elem *heads, unsigned count);
161 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
162 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
163 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
164
165 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
166 unsigned int log_num, u64 len);
167
168 #define vq_err(vq, fmt, ...) do { \
169 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
170 if ((vq)->error_ctx) \
171 eventfd_signal((vq)->error_ctx, 1);\
172 } while (0)
173
174 enum {
175 VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
176 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
177 (1ULL << VIRTIO_RING_F_EVENT_IDX) |
178 (1ULL << VHOST_F_LOG_ALL),
179 };
180
vhost_has_feature(struct vhost_dev * dev,int bit)181 static inline int vhost_has_feature(struct vhost_dev *dev, int bit)
182 {
183 unsigned acked_features;
184
185 /* TODO: check that we are running from vhost_worker or dev mutex is
186 * held? */
187 acked_features = rcu_dereference_index_check(dev->acked_features, 1);
188 return acked_features & (1 << bit);
189 }
190 #endif
191