projects / 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 | |
| 15 | * accesses through relaxed memory I/O windows, so smp_mb() et al are | |
| 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 | { | |
| 9e1a27ea | 26 | #ifdef CONFIG_SMP |
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27 | if (weak_barriers) |
| 28 | smp_mb(); | |
| 29 | else | |
| 9e1a27ea | 30 | #endif |
| a9a0fef7 RR |
31 | mb(); |
| 32 | } | |
| 33 | ||
| 34 | static inline void virtio_rmb(bool weak_barriers) | |
| 35 | { | |
| 36 | if (weak_barriers) | |
| 9e1a27ea | 37 | dma_rmb(); |
| a9a0fef7 RR |
38 | else |
| 39 | rmb(); | |
| 40 | } | |
| 41 | ||
| 42 | static inline void virtio_wmb(bool weak_barriers) | |
| 43 | { | |
| 44 | if (weak_barriers) | |
| 9e1a27ea | 45 | dma_wmb(); |
| a9a0fef7 RR |
46 | else |
| 47 | wmb(); | |
| 48 | } | |
| a9a0fef7 | 49 | |
| 0a8a69dd RR |
50 | struct virtio_device; |
| 51 | struct virtqueue; | |
| 52 | ||
| 17bb6d40 JW |
53 | struct virtqueue *vring_new_virtqueue(unsigned int index, |
| 54 | unsigned int num, | |
| 87c7d57c | 55 | unsigned int vring_align, |
| 0a8a69dd | 56 | struct virtio_device *vdev, |
| 7b21e34f | 57 | bool weak_barriers, |
| 0a8a69dd | 58 | void *pages, |
| 46f9c2b9 | 59 | bool (*notify)(struct virtqueue *vq), |
| 9499f5e7 RR |
60 | void (*callback)(struct virtqueue *vq), |
| 61 | const char *name); | |
| 0a8a69dd | 62 | void vring_del_virtqueue(struct virtqueue *vq); |
| e34f8725 RR |
63 | /* Filter out transport-specific feature bits. */ |
| 64 | void vring_transport_features(struct virtio_device *vdev); | |
| 0a8a69dd RR |
65 | |
| 66 | irqreturn_t vring_interrupt(int irq, void *_vq); | |
| 0a8a69dd | 67 | #endif /* _LINUX_VIRTIO_RING_H */ |