1 #ifndef _LINUX_VIRTIO_RING_H
2 #define _LINUX_VIRTIO_RING_H
4 #include <asm/barrier.h>
5 #include <linux/irqreturn.h>
6 #include <uapi/linux/virtio_ring.h>
9 * Barriers in virtio are tricky. Non-SMP virtio guests can't assume
10 * they're not on an SMP host system, so they need to assume real
11 * barriers. Non-SMP virtio hosts could skip the barriers, but does
14 * For virtio_pci on SMP, we don't need to order with respect to MMIO
15 * accesses through relaxed memory I/O windows, so virt_mb() et al are
18 * For using virtio to talk to real devices (eg. other heterogeneous
19 * CPUs) we do need real barriers. In theory, we could be using both
20 * kinds of virtio, so it's a runtime decision, and the branch is
21 * actually quite cheap.
24 static inline void virtio_mb(bool weak_barriers)
32 static inline void virtio_rmb(bool weak_barriers)
40 static inline void virtio_wmb(bool weak_barriers)
48 static inline void virtio_store_mb(bool weak_barriers,
49 __virtio16 *p, __virtio16 v)
62 struct virtqueue *vring_new_virtqueue(unsigned int index,
64 unsigned int vring_align,
65 struct virtio_device *vdev,
68 bool (*notify)(struct virtqueue *vq),
69 void (*callback)(struct virtqueue *vq),
71 void vring_del_virtqueue(struct virtqueue *vq);
72 /* Filter out transport-specific feature bits. */
73 void vring_transport_features(struct virtio_device *vdev);
75 irqreturn_t vring_interrupt(int irq, void *_vq);
76 #endif /* _LINUX_VIRTIO_RING_H */