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/pagemap.h>
16 #include <linux/mmu_notifier.h>
17 #include <asm/cacheflush.h>
20 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
22 #define VHOST_WORK_QUEUED 1
24 struct llist_node node;
29 /* Poll a file (eventfd or socket) */
30 /* Note: there's nothing vhost specific about this structure. */
33 wait_queue_head_t *wqh;
34 wait_queue_entry_t wait;
35 struct vhost_work work;
37 struct vhost_dev *dev;
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 bool vhost_has_work(struct vhost_dev *dev);
44 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
45 __poll_t mask, struct vhost_dev *dev);
46 int vhost_poll_start(struct vhost_poll *poll, struct file *file);
47 void vhost_poll_stop(struct vhost_poll *poll);
48 void vhost_poll_flush(struct vhost_poll *poll);
49 void vhost_poll_queue(struct vhost_poll *poll);
50 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work);
51 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
58 #define START(node) ((node)->start)
59 #define LAST(node) ((node)->last)
61 struct vhost_umem_node {
63 struct list_head link;
74 struct rb_root_cached umem_tree;
75 struct list_head umem_list;
79 enum vhost_uaddr_type {
98 #if defined(CONFIG_MMU_NOTIFIER) && ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 0
99 #define VHOST_ARCH_CAN_ACCEL_UACCESS 1
101 #define VHOST_ARCH_CAN_ACCEL_UACCESS 0
104 /* The virtqueue structure describes a queue attached to a device. */
105 struct vhost_virtqueue {
106 struct vhost_dev *dev;
108 /* The actual ring of buffers. */
111 struct vring_desc __user *desc;
112 struct vring_avail __user *avail;
113 struct vring_used __user *used;
115 #if VHOST_ARCH_CAN_ACCEL_UACCESS
116 /* Read by memory accessors, modified by meta data
117 * prefetching, MMU notifier and vring ioctl().
118 * Synchonrized through mmu_lock (writers) and RCU (writers
121 struct vhost_map __rcu *maps[VHOST_NUM_ADDRS];
122 /* Read by MMU notifier, modified by vring ioctl(),
123 * synchronized through MMU notifier
124 * registering/unregistering.
126 struct vhost_uaddr uaddrs[VHOST_NUM_ADDRS];
128 const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS];
131 struct eventfd_ctx *call_ctx;
132 struct eventfd_ctx *error_ctx;
133 struct eventfd_ctx *log_ctx;
135 struct vhost_poll poll;
137 /* The routine to call when the Guest pings us, or timeout. */
138 vhost_work_fn_t handle_kick;
140 /* Last available index we saw. */
143 /* Caches available index value from user. */
146 /* Last index we used. */
152 /* Last used index value we have signalled on */
155 /* Last used index value we have signalled on */
156 bool signalled_used_valid;
158 /* Log writes to used structure. */
162 struct iovec iov[UIO_MAXIOV];
163 struct iovec iotlb_iov[64];
164 struct iovec *indirect;
165 struct vring_used_elem *heads;
166 /* Protected by virtqueue mutex. */
167 struct vhost_umem *umem;
168 struct vhost_umem *iotlb;
171 u64 acked_backend_features;
172 /* Log write descriptors */
173 void __user *log_base;
174 struct vhost_log *log;
176 /* Ring endianness. Defaults to legacy native endianness.
177 * Set to true when starting a modern virtio device. */
179 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
180 /* Ring endianness requested by userspace for cross-endian support. */
183 u32 busyloop_timeout;
185 int invalidate_count;
188 struct vhost_msg_node {
190 struct vhost_msg msg;
191 struct vhost_msg_v2 msg_v2;
193 struct vhost_virtqueue *vq;
194 struct list_head node;
198 struct mm_struct *mm;
199 #ifdef CONFIG_MMU_NOTIFIER
200 struct mmu_notifier mmu_notifier;
203 struct vhost_virtqueue **vqs;
205 struct eventfd_ctx *log_ctx;
206 struct llist_head work_list;
207 struct task_struct *worker;
208 struct vhost_umem *umem;
209 struct vhost_umem *iotlb;
210 spinlock_t iotlb_lock;
211 struct list_head read_list;
212 struct list_head pending_list;
213 wait_queue_head_t wait;
219 bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
220 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
221 int nvqs, int iov_limit, int weight, int byte_weight);
222 long vhost_dev_set_owner(struct vhost_dev *dev);
223 bool vhost_dev_has_owner(struct vhost_dev *dev);
224 long vhost_dev_check_owner(struct vhost_dev *);
225 struct vhost_umem *vhost_dev_reset_owner_prepare(void);
226 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_umem *);
227 void vhost_dev_cleanup(struct vhost_dev *);
228 void vhost_dev_stop(struct vhost_dev *);
229 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
230 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
231 bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
232 bool vhost_log_access_ok(struct vhost_dev *);
234 int vhost_get_vq_desc(struct vhost_virtqueue *,
235 struct iovec iov[], unsigned int iov_count,
236 unsigned int *out_num, unsigned int *in_num,
237 struct vhost_log *log, unsigned int *log_num);
238 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
240 int vhost_vq_init_access(struct vhost_virtqueue *);
241 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
242 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
244 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
245 unsigned int id, int len);
246 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
247 struct vring_used_elem *heads, unsigned count);
248 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
249 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
250 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
251 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
253 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
254 unsigned int log_num, u64 len,
255 struct iovec *iov, int count);
256 int vq_meta_prefetch(struct vhost_virtqueue *vq);
258 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
259 void vhost_enqueue_msg(struct vhost_dev *dev,
260 struct list_head *head,
261 struct vhost_msg_node *node);
262 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
263 struct list_head *head);
264 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
266 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
268 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
269 struct iov_iter *from);
270 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
272 #define vq_err(vq, fmt, ...) do { \
273 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \
274 if ((vq)->error_ctx) \
275 eventfd_signal((vq)->error_ctx, 1);\
279 VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
280 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
281 (1ULL << VIRTIO_RING_F_EVENT_IDX) |
282 (1ULL << VHOST_F_LOG_ALL) |
283 (1ULL << VIRTIO_F_ANY_LAYOUT) |
284 (1ULL << VIRTIO_F_VERSION_1)
287 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
289 return vq->acked_features & (1ULL << bit);
292 static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
294 return vq->acked_backend_features & (1ULL << bit);
297 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
298 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
303 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
305 return virtio_legacy_is_little_endian() || vq->is_le;
309 /* Memory accessors */
310 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
312 return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
315 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
317 return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
320 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
322 return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
325 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
327 return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
330 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
332 return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
335 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
337 return __cpu_to_virtio64(vhost_is_little_endian(vq), val);