1 #ifndef _VHOST_H 2 #define _VHOST_H 3 4 #include <linux/eventfd.h> 5 #include <linux/vhost.h> 6 #include <linux/mm.h> 7 #include <linux/mutex.h> 8 #include <linux/poll.h> 9 #include <linux/file.h> 10 #include <linux/uio.h> 11 #include <linux/virtio_config.h> 12 #include <linux/virtio_ring.h> 13 #include <linux/atomic.h> 14 15 struct vhost_device; 16 17 struct vhost_work; 18 typedef void (*vhost_work_fn_t)(struct vhost_work *work); 19 20 struct vhost_work { 21 struct list_head 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 }; 28 29 /* Poll a file (eventfd or socket) */ 30 /* Note: there's nothing vhost specific about this structure. */ 31 struct vhost_poll { 32 poll_table table; 33 wait_queue_head_t *wqh; 34 wait_queue_t wait; 35 struct vhost_work work; 36 unsigned long mask; 37 struct vhost_dev *dev; 38 }; 39 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 43 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, 44 unsigned long mask, struct vhost_dev *dev); 45 int vhost_poll_start(struct vhost_poll *poll, struct file *file); 46 void vhost_poll_stop(struct vhost_poll *poll); 47 void vhost_poll_flush(struct vhost_poll *poll); 48 void vhost_poll_queue(struct vhost_poll *poll); 49 50 struct vhost_log { 51 u64 addr; 52 u64 len; 53 }; 54 55 struct vhost_virtqueue; 56 57 /* The virtqueue structure describes a queue attached to a device. */ 58 struct vhost_virtqueue { 59 struct vhost_dev *dev; 60 61 /* The actual ring of buffers. */ 62 struct mutex mutex; 63 unsigned int num; 64 struct vring_desc __user *desc; 65 struct vring_avail __user *avail; 66 struct vring_used __user *used; 67 struct file *kick; 68 struct file *call; 69 struct file *error; 70 struct eventfd_ctx *call_ctx; 71 struct eventfd_ctx *error_ctx; 72 struct eventfd_ctx *log_ctx; 73 74 struct vhost_poll poll; 75 76 /* The routine to call when the Guest pings us, or timeout. */ 77 vhost_work_fn_t handle_kick; 78 79 /* Last available index we saw. */ 80 u16 last_avail_idx; 81 82 /* Caches available index value from user. */ 83 u16 avail_idx; 84 85 /* Last index we used. */ 86 u16 last_used_idx; 87 88 /* Used flags */ 89 u16 used_flags; 90 91 /* Last used index value we have signalled on */ 92 u16 signalled_used; 93 94 /* Last used index value we have signalled on */ 95 bool signalled_used_valid; 96 97 /* Log writes to used structure. */ 98 bool log_used; 99 u64 log_addr; 100 101 struct iovec iov[UIO_MAXIOV]; 102 struct iovec *indirect; 103 struct vring_used_elem *heads; 104 /* We use a kind of RCU to access private pointer. 105 * All readers access it from worker, which makes it possible to 106 * flush the vhost_work instead of synchronize_rcu. Therefore readers do 107 * not need to call rcu_read_lock/rcu_read_unlock: the beginning of 108 * vhost_work execution acts instead of rcu_read_lock() and the end of 109 * vhost_work execution acts instead of rcu_read_unlock(). 110 * Writers use virtqueue mutex. */ 111 void __rcu *private_data; 112 /* Log write descriptors */ 113 void __user *log_base; 114 struct vhost_log *log; 115 }; 116 117 struct vhost_dev { 118 /* Readers use RCU to access memory table pointer 119 * log base pointer and features. 120 * Writers use mutex below.*/ 121 struct vhost_memory __rcu *memory; 122 struct mm_struct *mm; 123 struct mutex mutex; 124 unsigned acked_features; 125 struct vhost_virtqueue **vqs; 126 int nvqs; 127 struct file *log_file; 128 struct eventfd_ctx *log_ctx; 129 spinlock_t work_lock; 130 struct list_head work_list; 131 struct task_struct *worker; 132 }; 133 134 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs); 135 long vhost_dev_set_owner(struct vhost_dev *dev); 136 long vhost_dev_check_owner(struct vhost_dev *); 137 struct vhost_memory *vhost_dev_reset_owner_prepare(void); 138 void vhost_dev_reset_owner(struct vhost_dev *, struct vhost_memory *); 139 void vhost_dev_cleanup(struct vhost_dev *, bool locked); 140 void vhost_dev_stop(struct vhost_dev *); 141 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, void __user *argp); 142 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp); 143 int vhost_vq_access_ok(struct vhost_virtqueue *vq); 144 int vhost_log_access_ok(struct vhost_dev *); 145 146 int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *, 147 struct iovec iov[], unsigned int iov_count, 148 unsigned int *out_num, unsigned int *in_num, 149 struct vhost_log *log, unsigned int *log_num); 150 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n); 151 152 int vhost_init_used(struct vhost_virtqueue *); 153 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len); 154 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads, 155 unsigned count); 156 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *, 157 unsigned int id, int len); 158 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, 159 struct vring_used_elem *heads, unsigned count); 160 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); 161 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *); 162 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *); 163 164 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, 165 unsigned int log_num, u64 len); 166 167 #define vq_err(vq, fmt, ...) do { \ 168 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \ 169 if ((vq)->error_ctx) \ 170 eventfd_signal((vq)->error_ctx, 1);\ 171 } while (0) 172 173 enum { 174 VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | 175 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | 176 (1ULL << VIRTIO_RING_F_EVENT_IDX) | 177 (1ULL << VHOST_F_LOG_ALL), 178 }; 179 180 static inline int vhost_has_feature(struct vhost_dev *dev, int bit) 181 { 182 unsigned acked_features; 183 184 /* TODO: check that we are running from vhost_worker or dev mutex is 185 * held? */ 186 acked_features = rcu_dereference_index_check(dev->acked_features, 1); 187 return acked_features & (1 << bit); 188 } 189 #endif 190