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 <linux/atomic.h> 15 16 /* This is for zerocopy, used buffer len is set to 1 when lower device DMA 17 * done */ 18 #define VHOST_DMA_DONE_LEN 1 19 #define VHOST_DMA_CLEAR_LEN 0 20 21 struct vhost_device; 22 23 struct vhost_work; 24 typedef void (*vhost_work_fn_t)(struct vhost_work *work); 25 26 struct vhost_work { 27 struct list_head node; 28 vhost_work_fn_t fn; 29 wait_queue_head_t done; 30 int flushing; 31 unsigned queue_seq; 32 unsigned done_seq; 33 }; 34 35 /* Poll a file (eventfd or socket) */ 36 /* Note: there's nothing vhost specific about this structure. */ 37 struct vhost_poll { 38 poll_table table; 39 wait_queue_head_t *wqh; 40 wait_queue_t wait; 41 struct vhost_work work; 42 unsigned long mask; 43 struct vhost_dev *dev; 44 }; 45 46 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn); 47 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work); 48 49 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, 50 unsigned long mask, struct vhost_dev *dev); 51 void vhost_poll_start(struct vhost_poll *poll, struct file *file); 52 void vhost_poll_stop(struct vhost_poll *poll); 53 void vhost_poll_flush(struct vhost_poll *poll); 54 void vhost_poll_queue(struct vhost_poll *poll); 55 56 struct vhost_log { 57 u64 addr; 58 u64 len; 59 }; 60 61 struct vhost_virtqueue; 62 63 struct vhost_ubuf_ref { 64 struct kref kref; 65 wait_queue_head_t wait; 66 struct vhost_virtqueue *vq; 67 }; 68 69 struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *, bool zcopy); 70 void vhost_ubuf_put(struct vhost_ubuf_ref *); 71 void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *); 72 73 /* The virtqueue structure describes a queue attached to a device. */ 74 struct vhost_virtqueue { 75 struct vhost_dev *dev; 76 77 /* The actual ring of buffers. */ 78 struct mutex mutex; 79 unsigned int num; 80 struct vring_desc __user *desc; 81 struct vring_avail __user *avail; 82 struct vring_used __user *used; 83 struct file *kick; 84 struct file *call; 85 struct file *error; 86 struct eventfd_ctx *call_ctx; 87 struct eventfd_ctx *error_ctx; 88 struct eventfd_ctx *log_ctx; 89 90 struct vhost_poll poll; 91 92 /* The routine to call when the Guest pings us, or timeout. */ 93 vhost_work_fn_t handle_kick; 94 95 /* Last available index we saw. */ 96 u16 last_avail_idx; 97 98 /* Caches available index value from user. */ 99 u16 avail_idx; 100 101 /* Last index we used. */ 102 u16 last_used_idx; 103 104 /* Used flags */ 105 u16 used_flags; 106 107 /* Last used index value we have signalled on */ 108 u16 signalled_used; 109 110 /* Last used index value we have signalled on */ 111 bool signalled_used_valid; 112 113 /* Log writes to used structure. */ 114 bool log_used; 115 u64 log_addr; 116 117 struct iovec iov[UIO_MAXIOV]; 118 /* hdr is used to store the virtio header. 119 * Since each iovec has >= 1 byte length, we never need more than 120 * header length entries to store the header. */ 121 struct iovec hdr[sizeof(struct virtio_net_hdr_mrg_rxbuf)]; 122 struct iovec *indirect; 123 size_t vhost_hlen; 124 size_t sock_hlen; 125 struct vring_used_elem *heads; 126 /* We use a kind of RCU to access private pointer. 127 * All readers access it from worker, which makes it possible to 128 * flush the vhost_work instead of synchronize_rcu. Therefore readers do 129 * not need to call rcu_read_lock/rcu_read_unlock: the beginning of 130 * vhost_work execution acts instead of rcu_read_lock() and the end of 131 * vhost_work execution acts instead of rcu_read_unlock(). 132 * Writers use virtqueue mutex. */ 133 void __rcu *private_data; 134 /* Log write descriptors */ 135 void __user *log_base; 136 struct vhost_log *log; 137 /* vhost zerocopy support fields below: */ 138 /* last used idx for outstanding DMA zerocopy buffers */ 139 int upend_idx; 140 /* first used idx for DMA done zerocopy buffers */ 141 int done_idx; 142 /* an array of userspace buffers info */ 143 struct ubuf_info *ubuf_info; 144 /* Reference counting for outstanding ubufs. 145 * Protected by vq mutex. Writers must also take device mutex. */ 146 struct vhost_ubuf_ref *ubufs; 147 }; 148 149 struct vhost_dev { 150 /* Readers use RCU to access memory table pointer 151 * log base pointer and features. 152 * Writers use mutex below.*/ 153 struct vhost_memory __rcu *memory; 154 struct mm_struct *mm; 155 struct mutex mutex; 156 unsigned acked_features; 157 struct vhost_virtqueue *vqs; 158 int nvqs; 159 struct file *log_file; 160 struct eventfd_ctx *log_ctx; 161 spinlock_t work_lock; 162 struct list_head work_list; 163 struct task_struct *worker; 164 }; 165 166 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs); 167 long vhost_dev_check_owner(struct vhost_dev *); 168 long vhost_dev_reset_owner(struct vhost_dev *); 169 void vhost_dev_cleanup(struct vhost_dev *, bool locked); 170 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg); 171 int vhost_vq_access_ok(struct vhost_virtqueue *vq); 172 int vhost_log_access_ok(struct vhost_dev *); 173 174 int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *, 175 struct iovec iov[], unsigned int iov_count, 176 unsigned int *out_num, unsigned int *in_num, 177 struct vhost_log *log, unsigned int *log_num); 178 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n); 179 180 int vhost_init_used(struct vhost_virtqueue *); 181 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len); 182 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads, 183 unsigned count); 184 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *, 185 unsigned int id, int len); 186 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, 187 struct vring_used_elem *heads, unsigned count); 188 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); 189 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *); 190 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *); 191 192 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, 193 unsigned int log_num, u64 len); 194 void vhost_zerocopy_callback(struct ubuf_info *); 195 int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq); 196 197 #define vq_err(vq, fmt, ...) do { \ 198 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \ 199 if ((vq)->error_ctx) \ 200 eventfd_signal((vq)->error_ctx, 1);\ 201 } while (0) 202 203 enum { 204 VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | 205 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | 206 (1ULL << VIRTIO_RING_F_EVENT_IDX) | 207 (1ULL << VHOST_F_LOG_ALL), 208 VHOST_NET_FEATURES = VHOST_FEATURES | 209 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | 210 (1ULL << VIRTIO_NET_F_MRG_RXBUF), 211 }; 212 213 static inline int vhost_has_feature(struct vhost_dev *dev, int bit) 214 { 215 unsigned acked_features; 216 217 /* TODO: check that we are running from vhost_worker or dev mutex is 218 * held? */ 219 acked_features = rcu_dereference_index_check(dev->acked_features, 1); 220 return acked_features & (1 << bit); 221 } 222 223 void vhost_enable_zcopy(int vq); 224 225 #endif 226