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 enum { 19 /* Enough place for all fragments, head, and virtio net header. */ 20 VHOST_NET_MAX_SG = MAX_SKB_FRAGS + 2, 21 }; 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 /* The virtqueue structure describes a queue attached to a device. */ 59 struct vhost_virtqueue { 60 struct vhost_dev *dev; 61 62 /* The actual ring of buffers. */ 63 struct mutex mutex; 64 unsigned int num; 65 struct vring_desc __user *desc; 66 struct vring_avail __user *avail; 67 struct vring_used __user *used; 68 struct file *kick; 69 struct file *call; 70 struct file *error; 71 struct eventfd_ctx *call_ctx; 72 struct eventfd_ctx *error_ctx; 73 struct eventfd_ctx *log_ctx; 74 75 struct vhost_poll poll; 76 77 /* The routine to call when the Guest pings us, or timeout. */ 78 vhost_work_fn_t handle_kick; 79 80 /* Last available index we saw. */ 81 u16 last_avail_idx; 82 83 /* Caches available index value from user. */ 84 u16 avail_idx; 85 86 /* Last index we used. */ 87 u16 last_used_idx; 88 89 /* Used flags */ 90 u16 used_flags; 91 92 /* Log writes to used structure. */ 93 bool log_used; 94 u64 log_addr; 95 96 struct iovec indirect[VHOST_NET_MAX_SG]; 97 struct iovec iov[VHOST_NET_MAX_SG]; 98 struct iovec hdr[VHOST_NET_MAX_SG]; 99 size_t vhost_hlen; 100 size_t sock_hlen; 101 struct vring_used_elem heads[VHOST_NET_MAX_SG]; 102 /* We use a kind of RCU to access private pointer. 103 * All readers access it from worker, which makes it possible to 104 * flush the vhost_work instead of synchronize_rcu. Therefore readers do 105 * not need to call rcu_read_lock/rcu_read_unlock: the beginning of 106 * vhost_work execution acts instead of rcu_read_lock() and the end of 107 * vhost_work execution acts instead of rcu_read_lock(). 108 * Writers use virtqueue mutex. */ 109 void *private_data; 110 /* Log write descriptors */ 111 void __user *log_base; 112 struct vhost_log log[VHOST_NET_MAX_SG]; 113 }; 114 115 struct vhost_dev { 116 /* Readers use RCU to access memory table pointer 117 * log base pointer and features. 118 * Writers use mutex below.*/ 119 struct vhost_memory *memory; 120 struct mm_struct *mm; 121 struct mutex mutex; 122 unsigned acked_features; 123 struct vhost_virtqueue *vqs; 124 int nvqs; 125 struct file *log_file; 126 struct eventfd_ctx *log_ctx; 127 spinlock_t work_lock; 128 struct list_head work_list; 129 struct task_struct *worker; 130 }; 131 132 long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs); 133 long vhost_dev_check_owner(struct vhost_dev *); 134 long vhost_dev_reset_owner(struct vhost_dev *); 135 void vhost_dev_cleanup(struct vhost_dev *); 136 long vhost_dev_ioctl(struct vhost_dev *, unsigned int ioctl, unsigned long arg); 137 int vhost_vq_access_ok(struct vhost_virtqueue *vq); 138 int vhost_log_access_ok(struct vhost_dev *); 139 140 int vhost_get_vq_desc(struct vhost_dev *, struct vhost_virtqueue *, 141 struct iovec iov[], unsigned int iov_count, 142 unsigned int *out_num, unsigned int *in_num, 143 struct vhost_log *log, unsigned int *log_num); 144 void vhost_discard_vq_desc(struct vhost_virtqueue *, int n); 145 146 int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len); 147 int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads, 148 unsigned count); 149 void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *, 150 unsigned int id, int len); 151 void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *, 152 struct vring_used_elem *heads, unsigned count); 153 void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *); 154 void vhost_disable_notify(struct vhost_virtqueue *); 155 bool vhost_enable_notify(struct vhost_virtqueue *); 156 157 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, 158 unsigned int log_num, u64 len); 159 160 #define vq_err(vq, fmt, ...) do { \ 161 pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \ 162 if ((vq)->error_ctx) \ 163 eventfd_signal((vq)->error_ctx, 1);\ 164 } while (0) 165 166 enum { 167 VHOST_FEATURES = (1 << VIRTIO_F_NOTIFY_ON_EMPTY) | 168 (1 << VIRTIO_RING_F_INDIRECT_DESC) | 169 (1 << VHOST_F_LOG_ALL) | 170 (1 << VHOST_NET_F_VIRTIO_NET_HDR) | 171 (1 << VIRTIO_NET_F_MRG_RXBUF), 172 }; 173 174 static inline int vhost_has_feature(struct vhost_dev *dev, int bit) 175 { 176 unsigned acked_features = rcu_dereference(dev->acked_features); 177 return acked_features & (1 << bit); 178 } 179 180 #endif 181