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
21 struct vhost_device;
22
23 struct vhost_work;
24 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
25
26 struct 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. */
37 struct 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
46 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
47 unsigned long mask, struct vhost_dev *dev);
48 void vhost_poll_start(struct vhost_poll *poll, struct file *file);
49 void vhost_poll_stop(struct vhost_poll *poll);
50 void vhost_poll_flush(struct vhost_poll *poll);
51 void vhost_poll_queue(struct vhost_poll *poll);
52
53 struct vhost_log {
54 u64 addr;
55 u64 len;
56 };
57
58 struct vhost_virtqueue;
59
60 struct vhost_ubuf_ref {
61 struct kref kref;
62 wait_queue_head_t wait;
63 struct vhost_virtqueue *vq;
64 };
65
66 struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *, bool zcopy);
67 void vhost_ubuf_put(struct vhost_ubuf_ref *);
68 void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *);
69
70 /* The virtqueue structure describes a queue attached to a device. */
71 struct 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
146 struct 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
163 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
164 long vhost_dev_check_owner(struct vhost_dev *);
165 long vhost_dev_reset_owner(struct vhost_dev *);
166 void vhost_dev_cleanup(struct vhost_dev *, bool locked);
167 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg);
168 int vhost_vq_access_ok(struct vhost_virtqueue *vq);
169 int vhost_log_access_ok(struct vhost_dev *);
170
171 int 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);
175 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
176
177 int vhost_init_used(struct vhost_virtqueue *);
178 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
179 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
180 unsigned count);
181 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
182 unsigned int id, int len);
183 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
184 struct vring_used_elem *heads, unsigned count);
185 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
186 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
187 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
188
189 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
190 unsigned int log_num, u64 len);
191 void vhost_zerocopy_callback(struct ubuf_info *);
192 int 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
200 enum {
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
vhost_has_feature(struct vhost_dev * dev,int bit)209 static 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
219 void vhost_enable_zcopy(int vq);
220
221 #endif
222