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_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, 47 unsigned long mask, struct vhost_dev *dev); 48 void vhost_poll_start(struct vhost_poll *poll, struct file *file); 49 void vhost_poll_stop(struct vhost_poll *poll); 50 void vhost_poll_flush(struct vhost_poll *poll); 51 void vhost_poll_queue(struct vhost_poll *poll); 52 53 struct vhost_log { 54 u64 addr; 55 u64 len; 56 }; 57 58 struct vhost_virtqueue; 59 60 struct vhost_ubuf_ref { 61 struct kref kref; 62 wait_queue_head_t wait; 63 struct vhost_virtqueue *vq; 64 }; 65 66 struct vhost_ubuf_ref *vhost_ubuf_alloc(struct vhost_virtqueue *, bool zcopy); 67 void vhost_ubuf_put(struct vhost_ubuf_ref *); 68 void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *); 69 70 /* The virtqueue structure describes a queue attached to a device. */ 71 struct vhost_virtqueue { 72 struct vhost_dev *dev; 73 74 /* The actual ring of buffers. */ 75 struct mutex mutex; 76 unsigned int num; 77 struct vring_desc __user *desc; 78 struct vring_avail __user *avail; 79 struct vring_used __user *used; 80 struct file *kick; 81 struct file *call; 82 struct file *error; 83 struct eventfd_ctx *call_ctx; 84 struct eventfd_ctx *error_ctx; 85 struct eventfd_ctx *log_ctx; 86 87 struct vhost_poll poll; 88 89 /* The routine to call when the Guest pings us, or timeout. */ 90 vhost_work_fn_t handle_kick; 91 92 /* Last available index we saw. */ 93 u16 last_avail_idx; 94 95 /* Caches available index value from user. */ 96 u16 avail_idx; 97 98 /* Last index we used. */ 99 u16 last_used_idx; 100 101 /* Used flags */ 102 u16 used_flags; 103 104 /* Last used index value we have signalled on */ 105 u16 signalled_used; 106 107 /* Last used index value we have signalled on */ 108 bool signalled_used_valid; 109 110 /* Log writes to used structure. */ 111 bool log_used; 112 u64 log_addr; 113 114 struct iovec iov[UIO_MAXIOV]; 115 /* hdr is used to store the virtio header. 116 * Since each iovec has >= 1 byte length, we never need more than 117 * header length entries to store the header. */ 118 struct iovec hdr[sizeof(struct virtio_net_hdr_mrg_rxbuf)]; 119 struct iovec *indirect; 120 size_t vhost_hlen; 121 size_t sock_hlen; 122 struct vring_used_elem *heads; 123 /* We use a kind of RCU to access private pointer. 124 * All readers access it from worker, which makes it possible to 125 * flush the vhost_work instead of synchronize_rcu. Therefore readers do 126 * not need to call rcu_read_lock/rcu_read_unlock: the beginning of 127 * vhost_work execution acts instead of rcu_read_lock() and the end of 128 * vhost_work execution acts instead of rcu_read_unlock(). 129 * Writers use virtqueue mutex. */ 130 void __rcu *private_data; 131 /* Log write descriptors */ 132 void __user *log_base; 133 struct vhost_log *log; 134 /* vhost zerocopy support fields below: */ 135 /* last used idx for outstanding DMA zerocopy buffers */ 136 int upend_idx; 137 /* first used idx for DMA done zerocopy buffers */ 138 int done_idx; 139 /* an array of userspace buffers info */ 140 struct ubuf_info *ubuf_info; 141 /* Reference counting for outstanding ubufs. 142 * Protected by vq mutex. Writers must also take device mutex. */ 143 struct vhost_ubuf_ref *ubufs; 144 }; 145 146 struct vhost_dev { 147 /* Readers use RCU to access memory table pointer 148 * log base pointer and features. 149 * Writers use mutex below.*/ 150 struct vhost_memory __rcu *memory; 151 struct mm_struct *mm; 152 struct mutex mutex; 153 unsigned acked_features; 154 struct vhost_virtqueue *vqs; 155 int nvqs; 156 struct file *log_file; 157 struct eventfd_ctx *log_ctx; 158 spinlock_t work_lock; 159 struct list_head work_list; 160 struct task_struct *worker; 161 }; 162 163 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs); 164 long vhost_dev_check_owner(struct vhost_dev *); 165 long vhost_dev_reset_owner(struct vhost_dev *); 166 void vhost_dev_cleanup(struct vhost_dev *, bool locked); 167 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg); 168 int vhost_vq_access_ok(struct vhost_virtqueue *vq); 169 int vhost_log_access_ok(struct vhost_dev *); 170 171 int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *, 172 struct iovec iov[], unsigned int iov_count, 173 unsigned int *out_num, unsigned int *in_num, 174 struct vhost_log *log, unsigned int *log_num); 175 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n); 176 177 int vhost_init_used(struct vhost_virtqueue *); 178 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len); 179 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads, 180 unsigned count); 181 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *, 182 unsigned int id, int len); 183 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, 184 struct vring_used_elem *heads, unsigned count); 185 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); 186 void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *); 187 bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *); 188 189 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, 190 unsigned int log_num, u64 len); 191 void vhost_zerocopy_callback(struct ubuf_info *); 192 int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq); 193 194 #define vq_err(vq, fmt, ...) do { \ 195 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \ 196 if ((vq)->error_ctx) \ 197 eventfd_signal((vq)->error_ctx, 1);\ 198 } while (0) 199 200 enum { 201 VHOST_FEATURES = (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | 202 (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | 203 (1ULL << VIRTIO_RING_F_EVENT_IDX) | 204 (1ULL << VHOST_F_LOG_ALL) | 205 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | 206 (1ULL << VIRTIO_NET_F_MRG_RXBUF), 207 }; 208 209 static inline int vhost_has_feature(struct vhost_dev *dev, int bit) 210 { 211 unsigned acked_features; 212 213 /* TODO: check that we are running from vhost_worker or dev mutex is 214 * held? */ 215 acked_features = rcu_dereference_index_check(dev->acked_features, 1); 216 return acked_features & (1 << bit); 217 } 218 219 void vhost_enable_zcopy(int vq); 220 221 #endif 222