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
  16 struct vhost_work;
  17 typedef void (*vhost_work_fn_t)(struct vhost_work *work);
  18
  19 #define VHOST_WORK_QUEUED 1
  20 struct vhost_work {
  21         struct llist_node         node;
  22         vhost_work_fn_t           fn;
  23         unsigned long             flags;
  24 };
  25
  26 /* Poll a file (eventfd or socket) */
  27 /* Note: there's nothing vhost specific about this structure. */
  28 struct vhost_poll {
  29         poll_table                table;
  30         wait_queue_head_t        *wqh;
  31         wait_queue_entry_t              wait;
  32         struct vhost_work         work;
  33         __poll_t                  mask;
  34         struct vhost_dev         *dev;
  35 };
  36
  37 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
  38 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
  39 bool vhost_has_work(struct vhost_dev *dev);
  40
  41 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
  42                      __poll_t mask, struct vhost_dev *dev);
  43 int vhost_poll_start(struct vhost_poll *poll, struct file *file);
  44 void vhost_poll_stop(struct vhost_poll *poll);
  45 void vhost_poll_flush(struct vhost_poll *poll);
  46 void vhost_poll_queue(struct vhost_poll *poll);
  47 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work);
  48 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp);
  49
  50 struct vhost_log {
  51         u64 addr;
  52         u64 len;
  53 };
  54
  55 #define START(node) ((node)->start)
  56 #define LAST(node) ((node)->last)
  57
  58 struct vhost_umem_node {
  59         struct rb_node rb;
  60         struct list_head link;
  61         __u64 start;
  62         __u64 last;
  63         __u64 size;
  64         __u64 userspace_addr;
  65         __u32 perm;
  66         __u32 flags_padding;
  67         __u64 __subtree_last;
  68 };
  69
  70 struct vhost_umem {
  71         struct rb_root_cached umem_tree;
  72         struct list_head umem_list;
  73         int numem;
  74 };
  75
  76 enum vhost_uaddr_type {
  77         VHOST_ADDR_DESC = 0,
  78         VHOST_ADDR_AVAIL = 1,
  79         VHOST_ADDR_USED = 2,
  80         VHOST_NUM_ADDRS = 3,
  81 };
  82
  83 /* The virtqueue structure describes a queue attached to a device. */
  84 struct vhost_virtqueue {
  85         struct vhost_dev *dev;
  86
  87         /* The actual ring of buffers. */
  88         struct mutex mutex;
  89         unsigned int num;
  90         struct vring_desc __user *desc;
  91         struct vring_avail __user *avail;
  92         struct vring_used __user *used;
  93         const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS];
  94         struct file *kick;
  95         struct eventfd_ctx *call_ctx;
  96         struct eventfd_ctx *error_ctx;
  97         struct eventfd_ctx *log_ctx;
  98
  99         struct vhost_poll poll;
 100
 101         /* The routine to call when the Guest pings us, or timeout. */
 102         vhost_work_fn_t handle_kick;
 103
 104         /* Last available index we saw. */
 105         u16 last_avail_idx;
 106
 107         /* Caches available index value from user. */
 108         u16 avail_idx;
 109
 110         /* Last index we used. */
 111         u16 last_used_idx;
 112
 113         /* Used flags */
 114         u16 used_flags;
 115
 116         /* Last used index value we have signalled on */
 117         u16 signalled_used;
 118
 119         /* Last used index value we have signalled on */
 120         bool signalled_used_valid;
 121
 122         /* Log writes to used structure. */
 123         bool log_used;
 124         u64 log_addr;
 125
 126         struct iovec iov[UIO_MAXIOV];
 127         struct iovec iotlb_iov[64];
 128         struct iovec *indirect;
 129         struct vring_used_elem *heads;
 130         /* Protected by virtqueue mutex. */
 131         struct vhost_umem *umem;
 132         struct vhost_umem *iotlb;
 133         void *private_data;
 134         u64 acked_features;
 135         u64 acked_backend_features;
 136         /* Log write descriptors */
 137         void __user *log_base;
 138         struct vhost_log *log;
 139
 140         /* Ring endianness. Defaults to legacy native endianness.
 141          * Set to true when starting a modern virtio device. */
 142         bool is_le;
 143 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 144         /* Ring endianness requested by userspace for cross-endian support. */
 145         bool user_be;
 146 #endif
 147         u32 busyloop_timeout;
 148 };
 149
 150 struct vhost_msg_node {
 151   union {
 152           struct vhost_msg msg;
 153           struct vhost_msg_v2 msg_v2;
 154   };
 155   struct vhost_virtqueue *vq;
 156   struct list_head node;
 157 };
 158
 159 struct vhost_dev {
 160         struct mm_struct *mm;
 161         struct mutex mutex;
 162         struct vhost_virtqueue **vqs;
 163         int nvqs;
 164         struct eventfd_ctx *log_ctx;
 165         struct llist_head work_list;
 166         struct task_struct *worker;
 167         struct vhost_umem *umem;
 168         struct vhost_umem *iotlb;
 169         spinlock_t iotlb_lock;
 170         struct list_head read_list;
 171         struct list_head pending_list;
 172         wait_queue_head_t wait;
 173         int iov_limit;
 174 };
 175
 176 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
 177                     int nvqs, int iov_limit);
 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_umem *vhost_dev_reset_owner_prepare(void);
 182 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_umem *);
 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
 190 int vhost_get_vq_desc(struct vhost_virtqueue *,
 191                       struct iovec iov[], unsigned int iov_count,
 192                       unsigned int *out_num, unsigned int *in_num,
 193                       struct vhost_log *log, unsigned int *log_num);
 194 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 195
 196 int vhost_vq_init_access(struct vhost_virtqueue *);
 197 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 198 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 199                      unsigned count);
 200 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 201                                unsigned int id, int len);
 202 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 203                                struct vring_used_elem *heads, unsigned count);
 204 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 205 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 206 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
 207 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 208
 209 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 210                     unsigned int log_num, u64 len,
 211                     struct iovec *iov, int count);
 212 int vq_iotlb_prefetch(struct vhost_virtqueue *vq);
 213
 214 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
 215 void vhost_enqueue_msg(struct vhost_dev *dev,
 216                        struct list_head *head,
 217                        struct vhost_msg_node *node);
 218 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
 219                                          struct list_head *head);
 220 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
 221                             poll_table *wait);
 222 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
 223                             int noblock);
 224 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
 225                              struct iov_iter *from);
 226 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
 227
 228 #define vq_err(vq, fmt, ...) do {                                  \
 229                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 230                 if ((vq)->error_ctx)                               \
 231                                 eventfd_signal((vq)->error_ctx, 1);\
 232         } while (0)
 233
 234 enum {
 235         VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 236                          (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 237                          (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 238                          (1ULL << VHOST_F_LOG_ALL) |
 239                          (1ULL << VIRTIO_F_ANY_LAYOUT) |
 240                          (1ULL << VIRTIO_F_VERSION_1)
 241 };
 242
 243 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
 244 {
 245         return vq->acked_features & (1ULL << bit);
 246 }
 247
 248 static inline bool vhost_backend_has_feature(struct vhost_virtqueue *vq, int bit)
 249 {
 250         return vq->acked_backend_features & (1ULL << bit);
 251 }
 252
 253 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 254 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 255 {
 256         return vq->is_le;
 257 }
 258 #else
 259 static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 260 {
 261         return virtio_legacy_is_little_endian() || vq->is_le;
 262 }
 263 #endif
 264
 265 /* Memory accessors */
 266 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
 267 {
 268         return __virtio16_to_cpu(vhost_is_little_endian(vq), val);
 269 }
 270
 271 static inline __virtio16 cpu_to_vhost16(struct vhost_virtqueue *vq, u16 val)
 272 {
 273         return __cpu_to_virtio16(vhost_is_little_endian(vq), val);
 274 }
 275
 276 static inline u32 vhost32_to_cpu(struct vhost_virtqueue *vq, __virtio32 val)
 277 {
 278         return __virtio32_to_cpu(vhost_is_little_endian(vq), val);
 279 }
 280
 281 static inline __virtio32 cpu_to_vhost32(struct vhost_virtqueue *vq, u32 val)
 282 {
 283         return __cpu_to_virtio32(vhost_is_little_endian(vq), val);
 284 }
 285
 286 static inline u64 vhost64_to_cpu(struct vhost_virtqueue *vq, __virtio64 val)
 287 {
 288         return __virtio64_to_cpu(vhost_is_little_endian(vq), val);
 289 }
 290
 291 static inline __virtio64 cpu_to_vhost64(struct vhost_virtqueue *vq, u64 val)
 292 {
 293         return __cpu_to_virtio64(vhost_is_little_endian(vq), val);
 294 }
 295 #endif