projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 0a8a69dd RR |
1 | #ifndef _LINUX_VIRTIO_RING_H |
| 2 | #define _LINUX_VIRTIO_RING_H | |
| 0a8a69dd | 3 | |
| c5610a5d | 4 | #include <asm/barrier.h> |
| 0a8a69dd | 5 | #include <linux/irqreturn.h> |
| 607ca46e DH |
6 | #include <uapi/linux/virtio_ring.h> |
| 7 | ||
| a9a0fef7 RR |
8 | /* |
| 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 | |
| 12 | * anyone care? | |
| 13 | * | |
| 14 | * For virtio_pci on SMP, we don't need to order with respect to MMIO | |
| a6596127 | 15 | * accesses through relaxed memory I/O windows, so virt_mb() et al are |
| a9a0fef7 RR |
16 | * sufficient. |
| 17 | * | |
| 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. | |
| 22 | */ | |
| 23 | ||
| a9a0fef7 RR |
24 | static inline void virtio_mb(bool weak_barriers) |
| 25 | { | |
| 26 | if (weak_barriers) | |
| a6596127 | 27 | virt_mb(); |
| a9a0fef7 RR |
28 | else |
| 29 | mb(); | |
| 30 | } | |
| 31 | ||
| 32 | static inline void virtio_rmb(bool weak_barriers) | |
| 33 | { | |
| 34 | if (weak_barriers) | |
| a6596127 | 35 | virt_rmb(); |
| a9a0fef7 RR |
36 | else |
| 37 | rmb(); | |
| 38 | } | |
| 39 | ||
| 40 | static inline void virtio_wmb(bool weak_barriers) | |
| 41 | { | |
| 42 | if (weak_barriers) | |
| a6596127 | 43 | virt_wmb(); |
| a9a0fef7 RR |
44 | else |
| 45 | wmb(); | |
| 46 | } | |
| a9a0fef7 | 47 | |
| 788e5b3a MT |
48 | static inline void virtio_store_mb(bool weak_barriers, |
| 49 | __virtio16 *p, __virtio16 v) | |
| 50 | { | |
| 51 | if (weak_barriers) { | |
| 52 | virt_store_mb(*p, v); | |
| 53 | } else { | |
| 54 | WRITE_ONCE(*p, v); | |
| 55 | mb(); | |
| 56 | } | |
| 57 | } | |
| 58 | ||
| 0a8a69dd RR |
59 | struct virtio_device; |
| 60 | struct virtqueue; | |
| 61 | ||
| 17bb6d40 JW |
62 | struct virtqueue *vring_new_virtqueue(unsigned int index, |
| 63 | unsigned int num, | |
| 87c7d57c | 64 | unsigned int vring_align, |
| 0a8a69dd | 65 | struct virtio_device *vdev, |
| 7b21e34f | 66 | bool weak_barriers, |
| 0a8a69dd | 67 | void *pages, |
| 46f9c2b9 | 68 | bool (*notify)(struct virtqueue *vq), |
| 9499f5e7 RR |
69 | void (*callback)(struct virtqueue *vq), |
| 70 | const char *name); | |
| 0a8a69dd | 71 | void vring_del_virtqueue(struct virtqueue *vq); |
| e34f8725 RR |
72 | /* Filter out transport-specific feature bits. */ |
| 73 | void vring_transport_features(struct virtio_device *vdev); | |
| 0a8a69dd RR |
74 | |
| 75 | irqreturn_t vring_interrupt(int irq, void *_vq); | |
| 0a8a69dd | 76 | #endif /* _LINUX_VIRTIO_RING_H */ |