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