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/skbuff.h> 11 #include <linux/uio.h> 12 #include <linux/virtio_config.h> 13 #include <linux/virtio_ring.h> 14 #include <asm/atomic.h> 15 16 struct vhost_device; 17 18 struct vhost_work; 19 typedef void (*vhost_work_fn_t)(struct vhost_work *work); 20 21 struct vhost_work { 22 struct list_head node; 23 vhost_work_fn_t fn; 24 wait_queue_head_t done; 25 int flushing; 26 unsigned queue_seq; 27 unsigned done_seq; 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_t wait; 36 struct vhost_work work; 37 unsigned long mask; 38 struct vhost_dev *dev; 39 }; 40 41 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, 42 unsigned long mask, struct vhost_dev *dev); 43 void 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 48 struct vhost_log { 49 u64 addr; 50 u64 len; 51 }; 52 53 /* The virtqueue structure describes a queue attached to a device. */ 54 struct vhost_virtqueue { 55 struct vhost_dev *dev; 56 57 /* The actual ring of buffers. */ 58 struct mutex mutex; 59 unsigned int num; 60 struct vring_desc __user *desc; 61 struct vring_avail __user *avail; 62 struct vring_used __user *used; 63 struct file *kick; 64 struct file *call; 65 struct file *error; 66 struct eventfd_ctx *call_ctx; 67 struct eventfd_ctx *error_ctx; 68 struct eventfd_ctx *log_ctx; 69 70 struct vhost_poll poll; 71 72 /* The routine to call when the Guest pings us, or timeout. */ 73 vhost_work_fn_t handle_kick; 74 75 /* Last available index we saw. */ 76 u16 last_avail_idx; 77 78 /* Caches available index value from user. */ 79 u16 avail_idx; 80 81 /* Last index we used. */ 82 u16 last_used_idx; 83 84 /* Used flags */ 85 u16 used_flags; 86 87 /* Log writes to used structure. */ 88 bool log_used; 89 u64 log_addr; 90 91 struct iovec iov[UIO_MAXIOV]; 92 /* hdr is used to store the virtio header. 93 * Since each iovec has >= 1 byte length, we never need more than 94 * header length entries to store the header. */ 95 struct iovec hdr[sizeof(struct virtio_net_hdr_mrg_rxbuf)]; 96 struct iovec *indirect; 97 size_t vhost_hlen; 98 size_t sock_hlen; 99 struct vring_used_elem *heads; 100 /* We use a kind of RCU to access private pointer. 101 * All readers access it from worker, which makes it possible to 102 * flush the vhost_work instead of synchronize_rcu. Therefore readers do 103 * not need to call rcu_read_lock/rcu_read_unlock: the beginning of 104 * vhost_work execution acts instead of rcu_read_lock() and the end of 105 * vhost_work execution acts instead of rcu_read_lock(). 106 * Writers use virtqueue mutex. */ 107 void __rcu *private_data; 108 /* Log write descriptors */ 109 void __user *log_base; 110 struct vhost_log *log; 111 }; 112 113 struct vhost_dev { 114 /* Readers use RCU to access memory table pointer 115 * log base pointer and features. 116 * Writers use mutex below.*/ 117 struct vhost_memory __rcu *memory; 118 struct mm_struct *mm; 119 struct mutex mutex; 120 unsigned acked_features; 121 struct vhost_virtqueue *vqs; 122 int nvqs; 123 struct file *log_file; 124 struct eventfd_ctx *log_ctx; 125 spinlock_t work_lock; 126 struct list_head work_list; 127 struct task_struct *worker; 128 }; 129 130 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs); 131 long vhost_dev_check_owner(struct vhost_dev *); 132 long vhost_dev_reset_owner(struct vhost_dev *); 133 void vhost_dev_cleanup(struct vhost_dev *); 134 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg); 135 int vhost_vq_access_ok(struct vhost_virtqueue *vq); 136 int vhost_log_access_ok(struct vhost_dev *); 137 138 int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *, 139 struct iovec iov[], unsigned int iov_count, 140 unsigned int *out_num, unsigned int *in_num, 141 struct vhost_log *log, unsigned int *log_num); 142 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n); 143 144 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len); 145 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads, 146 unsigned count); 147 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *, 148 unsigned int id, int len); 149 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, 150 struct vring_used_elem *heads, unsigned count); 151 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); 152 void vhost_disable_notify(struct vhost_virtqueue *); 153 bool vhost_enable_notify(struct vhost_virtqueue *); 154 155 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, 156 unsigned int log_num, u64 len); 157 158 #define vq_err(vq, fmt, ...) do { \ 159 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \ 160 if ((vq)->error_ctx) \ 161 eventfd_signal((vq)->error_ctx, 1);\ 162 } while (0) 163 164 enum { 165 VHOST_FEATURES = (1 << VIRTIO_F_NOTIFY_ON_EMPTY) | 166 (1 << VIRTIO_RING_F_INDIRECT_DESC) | 167 (1 << VHOST_F_LOG_ALL) | 168 (1 << VHOST_NET_F_VIRTIO_NET_HDR) | 169 (1 << VIRTIO_NET_F_MRG_RXBUF), 170 }; 171 172 static inline int vhost_has_feature(struct vhost_dev *dev, int bit) 173 { 174 unsigned acked_features; 175 176 acked_features = 177 rcu_dereference_index_check(dev->acked_features, 178 lockdep_is_held(&dev->mutex)); 179 return acked_features & (1 << bit); 180 } 181 182 #endif 183