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         int weight;
 177         int byte_weight;
 178 };
 179
 180 bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
 181 void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
 182                     int nvqs, int weight, int byte_weight);
 183 long vhost_dev_set_owner(struct vhost_dev *dev);
 184 bool vhost_dev_has_owner(struct vhost_dev *dev);
 185 long vhost_dev_check_owner(struct vhost_dev *);
 186 struct vhost_umem *vhost_dev_reset_owner_prepare(void);
 187 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_umem *);
 188 void vhost_dev_cleanup(struct vhost_dev *, bool locked);
 189 void vhost_dev_stop(struct vhost_dev *);
 190 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp);
 191 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp);
 192 int vhost_vq_access_ok(struct vhost_virtqueue *vq);
 193 int vhost_log_access_ok(struct vhost_dev *);
 194
 195 int vhost_get_vq_desc(struct vhost_virtqueue *,
 196                       struct iovec iov[], unsigned int iov_count,
 197                       unsigned int *out_num, unsigned int *in_num,
 198                       struct vhost_log *log, unsigned int *log_num);
 199 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n);
 200
 201 int vhost_vq_init_access(struct vhost_virtqueue *);
 202 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
 203 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
 204                      unsigned count);
 205 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
 206                                unsigned int id, int len);
 207 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
 208                                struct vring_used_elem *heads, unsigned count);
 209 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
 210 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 211 bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
 212 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 213
 214 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 215                     unsigned int log_num, u64 len,
 216                     struct iovec *iov, int count);
 217 int vq_iotlb_prefetch(struct vhost_virtqueue *vq);
 218
 219 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type);
 220 void vhost_enqueue_msg(struct vhost_dev *dev,
 221                        struct list_head *head,
 222                        struct vhost_msg_node *node);
 223 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
 224                                          struct list_head *head);
 225 unsigned int vhost_chr_poll(struct file *file, struct vhost_dev *dev,
 226                             poll_table *wait);
 227 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
 228                             int noblock);
 229 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
 230                              struct iov_iter *from);
 231 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled);
 232
 233 #define vq_err(vq, fmt, ...) do {                                  \
 234                 pr_debug(pr_fmt(fmt), ##__VA_ARGS__);       \
 235                 if ((vq)->error_ctx)                               \
 236                                 eventfd_signal((vq)->error_ctx, 1);\
 237         } while (0)
 238
 239 enum {
 240         VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
 241                          (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
 242                          (1ULL << VIRTIO_RING_F_EVENT_IDX) |
 243                          (1ULL << VHOST_F_LOG_ALL) |
 244                          (1ULL << VIRTIO_F_ANY_LAYOUT) |
 245                          (1ULL << VIRTIO_F_VERSION_1)
 246 };
 247
 248 static inline bool vhost_has_feature(struct vhost_virtqueue *vq, int bit)
 249 {
 250         return vq->acked_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