/drivers/vhost/vhost.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _VHOST_H
  3#define _VHOST_H
  4
  5#include <linux/eventfd.h>
  6#include <linux/vhost.h>
  7#include <linux/mm.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
 17struct vhost_work;
 18typedef void (*vhost_work_fn_t)(struct vhost_work *work);
 19
 20#define VHOST_WORK_QUEUED 1
 21struct vhost_work {
 22	struct llist_node	  node;
 23	vhost_work_fn_t		  fn;
 24	unsigned long		  flags;
 25};
 26
 27/* Poll a file (eventfd or socket) */
 28/* Note: there's nothing vhost specific about this structure. */
 29struct vhost_poll {
 30	poll_table                table;
 31	wait_queue_head_t        *wqh;
 32	wait_queue_entry_t              wait;
 33	struct vhost_work	  work;
 34	__poll_t		  mask;
 35	struct vhost_dev	 *dev;
 36};
 37
 38void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
 39void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
 40bool vhost_has_work(struct vhost_dev *dev);
 41
 42void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
 43		     __poll_t mask, struct vhost_dev *dev);
 44int vhost_poll_start(struct vhost_poll *poll, struct file *file);
 45void vhost_poll_stop(struct vhost_poll *poll);
 46void vhost_poll_flush(struct vhost_poll *poll);
 47void vhost_poll_queue(struct vhost_poll *poll);
 48void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work);
 49long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
 50
 51struct vhost_log {
 52	u64 addr;
 53	u64 len;
 54};
 55
 56enum vhost_uaddr_type {
 57	VHOST_ADDR_DESC = 0,
 58	VHOST_ADDR_AVAIL = 1,
 59	VHOST_ADDR_USED = 2,
 60	VHOST_NUM_ADDRS = 3,
 61};
 62
 63/* The virtqueue structure describes a queue attached to a device. */
 64struct vhost_virtqueue {
 65	struct vhost_dev *dev;
 66
 67	/* The actual ring of buffers. */
 68	struct mutex mutex;
 69	unsigned int num;
 70	struct vring_desc __user *desc;
 71	struct vring_avail __user *avail;
 72	struct vring_used __user *used;
 73	const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
 74	struct file *kick;
 75	struct eventfd_ctx *call_ctx;
 76	struct eventfd_ctx *error_ctx;
 77	struct eventfd_ctx *log_ctx;
 78
 79	struct vhost_poll poll;
 80
 81	/* The routine to call when the Guest pings us, or timeout. */
 82	vhost_work_fn_t handle_kick;
 83
 84	/* Last available index we saw. */
 85	u16 last_avail_idx;
 86
 87	/* Caches available index value from user. */
 88	u16 avail_idx;
 89
 90	/* Last index we used. */
 91	u16 last_used_idx;
 92
 93	/* Used flags */
 94	u16 used_flags;
 95
 96	/* Last used index value we have signalled on */
 97	u16 signalled_used;
 98
 99	/* Last used index value we have signalled on */
100	bool signalled_used_valid;
101
102	/* Log writes to used structure. */
103	bool log_used;
104	u64 log_addr;
105
106	struct iovec iov[UIO_MAXIOV];
107	struct iovec iotlb_iov[64];
108	struct iovec *indirect;
109	struct vring_used_elem *heads;
110	/* Protected by virtqueue mutex. */
111	struct vhost_iotlb *umem;
112	struct vhost_iotlb *iotlb;
113	void *private_data;
114	u64 acked_features;
115	u64 acked_backend_features;
116	/* Log write descriptors */
117	void __user *log_base;
118	struct vhost_log *log;
119
120	/* Ring endianness. Defaults to legacy native endianness.
121	 * Set to true when starting a modern virtio device. */
122	bool is_le;
123#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
124	/* Ring endianness requested by userspace for cross-endian support. */
125	bool user_be;
126#endif
127	u32 busyloop_timeout;
128};
129
130struct vhost_msg_node {
131  union {
132	  struct vhost_msg msg;
133	  struct vhost_msg_v2 msg_v2;
134  };
135  struct vhost_virtqueue *vq;
136  struct list_head node;
137};
138
139struct vhost_dev {
140	struct mm_struct *mm;
141	struct mutex mutex;
142	struct vhost_virtqueue **vqs;
143	int nvqs;
144	struct eventfd_ctx *log_ctx;
145	struct llist_head work_list;
146	struct task_struct *worker;
147	struct vhost_iotlb *umem;
148	struct vhost_iotlb *iotlb;
149	spinlock_t iotlb_lock;
150	struct list_head read_list;
151	struct list_head pending_list;
152	wait_queue_head_t wait;
153	int iov_limit;
154	int weight;
155	int byte_weight;
156	u64 kcov_handle;
157	int (*msg_handler)(struct vhost_dev *dev,
158			   struct vhost_iotlb_msg *msg);
159};
160
161bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
162void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
163		    int nvqs, int iov_limit, int weight, int byte_weight,
164		    int (*msg_handler)(struct vhost_dev *dev,
165				       struct vhost_iotlb_msg *msg));
166long vhost_dev_set_owner(struct vhost_dev *dev);
167bool vhost_dev_has_owner(struct vhost_dev *dev);
168long vhost_dev_check_owner(struct vhost_dev *);
169struct vhost_iotlb *vhost_dev_reset_owner_prepare(void);
170void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *iotlb);
171void vhost_dev_cleanup(struct vhost_dev *);
172void vhost_dev_stop(struct vhost_dev *);
173long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
174long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
175bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
176bool vhost_log_access_ok(struct vhost_dev *);
177
178int vhost_get_vq_desc(struct vhost_virtqueue *,
179		      struct iovec iov[], unsigned int iov_count,
180		      unsigned int *out_num, unsigned int *in_num,
181		      struct vhost_log *log, unsigned int *log_num);
182void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
183
184int vhost_vq_init_access(struct vhost_virtqueue *);
185int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
186int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
187		     unsigned count);
188void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
189			       unsigned int id, int len);
190void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
191			       struct vring_used_elem *heads, unsigned count);
192void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
193void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
194bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
195bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
196
197int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
198		    unsigned int log_num, u64 len,
199		    struct iovec *iov, int count);
200int vq_meta_prefetch(struct vhost_virtqueue *vq);
201
202struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
203void vhost_enqueue_msg(struct vhost_dev *dev,
204		       struct list_head *head,
205		       struct vhost_msg_node *node);
206struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
207					 struct list_head *head);
208__poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
209			    poll_table *wait);
210ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
211			    int noblock);
212ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
213			     struct iov_iter *from);
214int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
215
216void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
217			  struct vhost_iotlb_map *map);
218
219#define vq_err(vq, fmt, ...) do {                                  \
220		pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
221		if ((vq)->error_ctx)                               \
222				eventfd_signal((vq)->error_ctx, 1);\
223	} while (0)
224
225enum {
226	VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
227			 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
228			 (1ULL << VIRTIO_RING_F_EVENT_IDX) |
229			 (1ULL << VHOST_F_LOG_ALL) |
230			 (1ULL << VIRTIO_F_ANY_LAYOUT) |
231			 (1ULL << VIRTIO_F_VERSION_1)
232};
233
234/**
235 * vhost_vq_set_backend - Set backend.
236 *
237 * @vq            Virtqueue.
238 * @private_data  The private data.
239 *
240 * Context: Need to call with vq->mutex acquired.
241 */
242static inline void vhost_vq_set_backend(struct vhost_virtqueue *vq,
243					void *private_data)
244{
245	vq->private_data = private_data;
246}
247
248/**
249 * vhost_vq_get_backend - Get backend.
250 *
251 * @vq            Virtqueue.
252 *
253 * Context: Need to call with vq->mutex acquired.
254 * Return: Private data previously set with vhost_vq_set_backend.
255 */
256static inline void *vhost_vq_get_backend(struct vhost_virtqueue *vq)
257{
258	return vq->private_data;
259}
260
261static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
262{
263	return vq->acked_features & (1ULL << bit);
264}
265
266static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
267{
268	return vq->acked_backend_features & (1ULL << bit);
269}
270
271#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
272static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
273{
274	return vq->is_le;
275}
276#else
277static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
278{
279	return virtio_legacy_is_little_endian() || vq->is_le;
280}
281#endif
282
283/* Memory accessors */
284static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
285{
286	return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
287}
288
289static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
290{
291	return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
292}
293
294static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
295{
296	return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
297}
298
299static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
300{
301	return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
302}
303
304static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
305{
306	return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
307}
308
309static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
310{
311	return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
312}
313#endif