1 /* SPDX-License-Identifier: GPL-2.0 */
5 #include <linux/eventfd.h>
6 #include <linux/vhost.h>
8 #include <linux/mutex.h>
9 #include <linux/poll.h>
10 #include <linux/file.h>
11 #include <linux/uio.h>
12 #include <linux/virtio_config.h>
13 #include <linux/virtio_ring.h>
14 #include <linux/atomic.h>
15 #include <linux/vhost_iotlb.h>
16 #include <linux/irqbypass.h>
20 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
22 #define VHOST_WORK_QUEUED 1
24 struct llist_node node;
30 struct vhost_task *vtsk;
31 struct llist_head work_list;
35 /* Poll a file (eventfd or socket) */
36 /* Note: there's nothing vhost specific about this structure. */
39 wait_queue_head_t *wqh;
40 wait_queue_entry_t wait;
41 struct vhost_work work;
43 struct vhost_dev *dev;
46 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
47 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
48 bool vhost_has_work(struct vhost_dev *dev);
50 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
51 __poll_t mask, struct vhost_dev *dev);
52 int vhost_poll_start(struct vhost_poll *poll, struct file *file);
53 void vhost_poll_stop(struct vhost_poll *poll);
54 void vhost_poll_queue(struct vhost_poll *poll);
55 void vhost_dev_flush(struct vhost_dev *dev);
62 enum vhost_uaddr_type {
69 struct vhost_vring_call {
70 struct eventfd_ctx *ctx;
71 struct irq_bypass_producer producer;
74 /* The virtqueue structure describes a queue attached to a device. */
75 struct vhost_virtqueue {
76 struct vhost_dev *dev;
78 /* The actual ring of buffers. */
81 vring_desc_t __user *desc;
82 vring_avail_t __user *avail;
83 vring_used_t __user *used;
84 const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
86 struct vhost_vring_call call_ctx;
87 struct eventfd_ctx *error_ctx;
88 struct eventfd_ctx *log_ctx;
90 struct vhost_poll poll;
92 /* The routine to call when the Guest pings us, or timeout. */
93 vhost_work_fn_t handle_kick;
95 /* Last available index we saw. */
98 /* Caches available index value from user. */
101 /* Last index we used. */
107 /* Last used index value we have signalled on */
110 /* Last used index value we have signalled on */
111 bool signalled_used_valid;
113 /* Log writes to used structure. */
117 struct iovec iov[UIO_MAXIOV];
118 struct iovec iotlb_iov[64];
119 struct iovec *indirect;
120 struct vring_used_elem *heads;
121 /* Protected by virtqueue mutex. */
122 struct vhost_iotlb *umem;
123 struct vhost_iotlb *iotlb;
126 u64 acked_backend_features;
127 /* Log write descriptors */
128 void __user *log_base;
129 struct vhost_log *log;
130 struct iovec log_iov[64];
132 /* Ring endianness. Defaults to legacy native endianness.
133 * Set to true when starting a modern virtio device. */
135 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
136 /* Ring endianness requested by userspace for cross-endian support. */
139 u32 busyloop_timeout;
142 struct vhost_msg_node {
144 struct vhost_msg msg;
145 struct vhost_msg_v2 msg_v2;
147 struct vhost_virtqueue *vq;
148 struct list_head node;
152 struct mm_struct *mm;
154 struct vhost_virtqueue **vqs;
156 struct eventfd_ctx *log_ctx;
157 struct vhost_worker *worker;
158 struct vhost_iotlb *umem;
159 struct vhost_iotlb *iotlb;
160 spinlock_t iotlb_lock;
161 struct list_head read_list;
162 struct list_head pending_list;
163 wait_queue_head_t wait;
168 int (*msg_handler)(struct vhost_dev *dev, u32 asid,
169 struct vhost_iotlb_msg *msg);
172 bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
173 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
174 int nvqs, int iov_limit, int weight, int byte_weight,
176 int (*msg_handler)(struct vhost_dev *dev, u32 asid,
177 struct vhost_iotlb_msg *msg));
178 long vhost_dev_set_owner(struct vhost_dev *dev);
179 bool vhost_dev_has_owner(struct vhost_dev *dev);
180 long vhost_dev_check_owner(struct vhost_dev *);
181 struct vhost_iotlb *vhost_dev_reset_owner_prepare(void);
182 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *iotlb);
183 void vhost_dev_cleanup(struct vhost_dev *);
184 void vhost_dev_stop(struct vhost_dev *);
185 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
186 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
187 bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
188 bool vhost_log_access_ok(struct vhost_dev *);
189 void vhost_clear_msg(struct vhost_dev *dev);
191 int vhost_get_vq_desc(struct vhost_virtqueue *,
192 struct iovec iov[], unsigned int iov_count,
193 unsigned int *out_num, unsigned int *in_num,
194 struct vhost_log *log, unsigned int *log_num);
195 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
197 bool vhost_vq_is_setup(struct vhost_virtqueue *vq);
198 int vhost_vq_init_access(struct vhost_virtqueue *);
199 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
200 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
202 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
203 unsigned int id, int len);
204 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
205 struct vring_used_elem *heads, unsigned count);
206 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
207 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
208 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
209 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
211 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
212 unsigned int log_num, u64 len,
213 struct iovec *iov, int count);
214 int vq_meta_prefetch(struct vhost_virtqueue *vq);
216 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
217 void vhost_enqueue_msg(struct vhost_dev *dev,
218 struct list_head *head,
219 struct vhost_msg_node *node);
220 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
221 struct list_head *head);
222 void vhost_set_backend_features(struct vhost_dev *dev, u64 features);
224 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
226 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
228 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
229 struct iov_iter *from);
230 int vhost_init_device_iotlb(struct vhost_dev *d);
232 void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
233 struct vhost_iotlb_map *map);
235 #define vq_err(vq, fmt, ...) do { \
236 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
237 if ((vq)->error_ctx) \
238 eventfd_signal((vq)->error_ctx, 1);\
242 VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
243 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
244 (1ULL << VIRTIO_RING_F_EVENT_IDX) |
245 (1ULL << VHOST_F_LOG_ALL) |
246 (1ULL << VIRTIO_F_ANY_LAYOUT) |
247 (1ULL << VIRTIO_F_VERSION_1)
251 * vhost_vq_set_backend - Set backend.
254 * @private_data The private data.
256 * Context: Need to call with vq->mutex acquired.
258 static inline void vhost_vq_set_backend(struct vhost_virtqueue *vq,
261 vq->private_data = private_data;
265 * vhost_vq_get_backend - Get backend.
269 * Context: Need to call with vq->mutex acquired.
270 * Return: Private data previously set with vhost_vq_set_backend.
272 static inline void *vhost_vq_get_backend(struct vhost_virtqueue *vq)
274 return vq->private_data;
277 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
279 return vq->acked_features & (1ULL << bit);
282 static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
284 return vq->acked_backend_features & (1ULL << bit);
287 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
288 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
293 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
295 return virtio_legacy_is_little_endian() || vq->is_le;
299 /* Memory accessors */
300 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
302 return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
305 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
307 return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
310 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
312 return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
315 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
317 return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
320 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
322 return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
325 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
327 return __cpu_to_virtio64(vhost_is_little_endian(vq), val);