LXR linux/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#include <linux/irqbypass.h>
  17
  18struct vhost_work;
  19typedef void (*vhost_work_fn_t)(struct vhost_work *work);
  20
  21#define VHOST_WORK_QUEUED 1
  22struct vhost_work {
  23        struct llist_node       node;
  24        vhost_work_fn_t         fn;
  25        unsigned long           flags;
  26};
  27
  28/* Poll a file (eventfd or socket) */
  29/* Note: there's nothing vhost specific about this structure. */
  30struct vhost_poll {
  31        poll_table              table;
  32        wait_queue_head_t       *wqh;
  33        wait_queue_entry_t      wait;
  34        struct vhost_work       work;
  35        __poll_t                mask;
  36        struct vhost_dev        *dev;
  37};
  38
  39void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
  40void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
  41bool vhost_has_work(struct vhost_dev *dev);
  42
  43void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
  44                     __poll_t mask, struct vhost_dev *dev);
  45int vhost_poll_start(struct vhost_poll *poll, struct file *file);
  46void vhost_poll_stop(struct vhost_poll *poll);
  47void vhost_poll_flush(struct vhost_poll *poll);
  48void vhost_poll_queue(struct vhost_poll *poll);
  49void vhost_work_dev_flush(struct vhost_dev *dev);
  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
  63struct vhost_vring_call {
  64        struct eventfd_ctx *ctx;
  65        struct irq_bypass_producer producer;
  66};
  67
  68/* The virtqueue structure describes a queue attached to a device. */
  69struct vhost_virtqueue {
  70        struct vhost_dev *dev;
  71
  72        /* The actual ring of buffers. */
  73        struct mutex mutex;
  74        unsigned int num;
  75        vring_desc_t __user *desc;
  76        vring_avail_t __user *avail;
  77        vring_used_t __user *used;
  78        const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
  79        struct file *kick;
  80        struct vhost_vring_call call_ctx;
  81        struct eventfd_ctx *error_ctx;
  82        struct eventfd_ctx *log_ctx;
  83
  84        struct vhost_poll poll;
  85
  86        /* The routine to call when the Guest pings us, or timeout. */
  87        vhost_work_fn_t handle_kick;
  88
  89        /* Last available index we saw. */
  90        u16 last_avail_idx;
  91
  92        /* Caches available index value from user. */
  93        u16 avail_idx;
  94
  95        /* Last index we used. */
  96        u16 last_used_idx;
  97
  98        /* Used flags */
  99        u16 used_flags;
 100
 101        /* Last used index value we have signalled on */
 102        u16 signalled_used;
 103
 104        /* Last used index value we have signalled on */
 105        bool signalled_used_valid;
 106
 107        /* Log writes to used structure. */
 108        bool log_used;
 109        u64 log_addr;
 110
 111        struct iovec iov[UIO_MAXIOV];
 112        struct iovec iotlb_iov[64];
 113        struct iovec *indirect;
 114        struct vring_used_elem *heads;
 115        /* Protected by virtqueue mutex. */
 116        struct vhost_iotlb *umem;
 117        struct vhost_iotlb *iotlb;
 118        void *private_data;
 119        u64 acked_features;
 120        u64 acked_backend_features;
 121        /* Log write descriptors */
 122        void __user *log_base;
 123        struct vhost_log *log;
 124        struct iovec log_iov[64];
 125
 126        /* Ring endianness. Defaults to legacy native endianness.
 127         * Set to true when starting a modern virtio device. */
 128        bool is_le;
 129#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 130        /* Ring endianness requested by userspace for cross-endian support. */
 131        bool user_be;
 132#endif
 133        u32 busyloop_timeout;
 134};
 135
 136struct vhost_msg_node {
 137  union {
 138          struct vhost_msg msg;
 139          struct vhost_msg_v2 msg_v2;
 140  };
 141  struct vhost_virtqueue *vq;
 142  struct list_head node;
 143};
 144
 145struct vhost_dev {
 146        struct mm_struct *mm;
 147        struct mutex mutex;
 148        struct vhost_virtqueue **vqs;
 149        int nvqs;
 150        struct eventfd_ctx *log_ctx;
 151        struct llist_head work_list;
 152        struct task_struct *worker;
 153        struct vhost_iotlb *umem;
 154        struct vhost_iotlb *iotlb;
 155        spinlock_t iotlb_lock;
 156        struct list_head read_list;
 157        struct list_head pending_list;
 158        wait_queue_head_t wait;
 159        int iov_limit;
 160        int weight;
 161        int byte_weight;
 162        u64 kcov_handle;
 163        bool use_worker;
 164        int (*msg_handler)(struct vhost_dev *dev,
 165                           struct vhost_iotlb_msg *msg);
 166};
 167
 168bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
 169void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
 170                    int nvqs, int iov_limit, int weight, int byte_weight,
 171                    bool use_worker,
 172                    int (*msg_handler)(struct vhost_dev *dev,
 173                                       struct vhost_iotlb_msg *msg));
 174long vhost_dev_set_owner(struct vhost_dev *dev);
 175bool vhost_dev_has_owner(struct vhost_dev *dev);
 176long vhost_dev_check_owner(struct vhost_dev *);
 177struct vhost_iotlb *vhost_dev_reset_owner_prepare(void);
 178void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *iotlb);
 179void vhost_dev_cleanup(struct vhost_dev *);
 180void vhost_dev_stop(struct vhost_dev *);
 181long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
 182long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
 183bool vhost_vq_access_ok(struct vhost_virtqueue *vq);
 184bool vhost_log_access_ok(struct vhost_dev *);
 185
 186int vhost_get_vq_desc(struct vhost_virtqueue *,
 187                      struct iovec iov[], unsigned int iov_count,
 188                      unsigned int *out_num, unsigned int *in_num,
 189                      struct vhost_log *log, unsigned int *log_num);
 190void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 191
 192bool vhost_vq_is_setup(struct vhost_virtqueue *vq);
 193int vhost_vq_init_access(struct vhost_virtqueue *);
 194int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 195int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 196                     unsigned count);
 197void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 198                               unsigned int id, int len);
 199void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 200                               struct vring_used_elem *heads, unsigned count);
 201void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 202void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 203bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
 204bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 205
 206int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 207                    unsigned int log_num, u64 len,
 208                    struct iovec *iov, int count);
 209int vq_meta_prefetch(struct vhost_virtqueue *vq);
 210
 211struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
 212void vhost_enqueue_msg(struct vhost_dev *dev,
 213                       struct list_head *head,
 214                       struct vhost_msg_node *node);
 215struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
 216                                         struct list_head *head);
 217void vhost_set_backend_features(struct vhost_dev *dev, u64 features);
 218
 219__poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
 220                            poll_table *wait);
 221ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
 222                            int noblock);
 223ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
 224                             struct iov_iter *from);
 225int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
 226
 227void vhost_iotlb_map_free(struct vhost_iotlb *iotlb,
 228                          struct vhost_iotlb_map *map);
 229
 230#define vq_err(vq, fmt, ...) do {                                  \
 231                pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 232                if ((vq)->error_ctx)                               \
 233                                eventfd_signal((vq)->error_ctx, 1);\
 234        } while (0)
 235
 236enum {
 237        VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 238                         (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 239                         (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 240                         (1ULL << VHOST_F_LOG_ALL) |
 241                         (1ULL << VIRTIO_F_ANY_LAYOUT) |
 242                         (1ULL << VIRTIO_F_VERSION_1)
 243};
 244
 245/**
 246 * vhost_vq_set_backend - Set backend.
 247 *
 248 * @vq            Virtqueue.
 249 * @private_data  The private data.
 250 *
 251 * Context: Need to call with vq->mutex acquired.
 252 */
 253static inline void vhost_vq_set_backend(struct vhost_virtqueue *vq,
 254                                        void *private_data)
 255{
 256        vq->private_data = private_data;
 257}
 258
 259/**
 260 * vhost_vq_get_backend - Get backend.
 261 *
 262 * @vq            Virtqueue.
 263 *
 264 * Context: Need to call with vq->mutex acquired.
 265 * Return: Private data previously set with vhost_vq_set_backend.
 266 */
 267static inline void *vhost_vq_get_backend(struct vhost_virtqueue *vq)
 268{
 269        return vq->private_data;
 270}
 271
 272static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
 273{
 274        return vq->acked_features & (1ULL << bit);
 275}
 276
 277static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
 278{
 279        return vq->acked_backend_features & (1ULL << bit);
 280}
 281
 282#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 283static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 284{
 285        return vq->is_le;
 286}
 287#else
 288static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 289{
 290        return virtio_legacy_is_little_endian() || vq->is_le;
 291}
 292#endif
 293
 294/* Memory accessors */
 295static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
 296{
 297        return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
 298}
 299
 300static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
 301{
 302        return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
 303}
 304
 305static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
 306{
 307        return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
 308}
 309
 310static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
 311{
 312        return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
 313}
 314
 315static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
 316{
 317        return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
 318}
 319
 320static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
 321{
 322        return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
 323}
 324#endif
 325