projects / mirror_ubuntu-artful-kernel.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 | ||
| 24 | #ifdef CONFIG_SMP | |
| 25 | static inline void virtio_mb(bool weak_barriers) | |
| 26 | { | |
| 27 | if (weak_barriers) | |
| 28 | smp_mb(); | |
| 29 | else | |
| 30 | mb(); | |
| 31 | } | |
| 32 | ||
| 33 | static inline void virtio_rmb(bool weak_barriers) | |
| 34 | { | |
| 35 | if (weak_barriers) | |
| 36 | smp_rmb(); | |
| 37 | else | |
| 38 | rmb(); | |
| 39 | } | |
| 40 | ||
| 41 | static inline void virtio_wmb(bool weak_barriers) | |
| 42 | { | |
| 43 | if (weak_barriers) | |
| 44 | smp_wmb(); | |
| 45 | else | |
| 46 | wmb(); | |
| 47 | } | |
| 48 | #else | |
| 49 | static inline void virtio_mb(bool weak_barriers) | |
| 50 | { | |
| 51 | mb(); | |
| 52 | } | |
| 53 | ||
| 54 | static inline void virtio_rmb(bool weak_barriers) | |
| 55 | { | |
| 56 | rmb(); | |
| 57 | } | |
| 58 | ||
| 59 | static inline void virtio_wmb(bool weak_barriers) | |
| 60 | { | |
| 61 | wmb(); | |
| 62 | } | |
| 63 | #endif | |
| 64 | ||
| 0a8a69dd RR |
65 | struct virtio_device; |
| 66 | struct virtqueue; | |
| 67 | ||
| 17bb6d40 JW |
68 | struct virtqueue *vring_new_virtqueue(unsigned int index, |
| 69 | unsigned int num, | |
| 87c7d57c | 70 | unsigned int vring_align, |
| 0a8a69dd | 71 | struct virtio_device *vdev, |
| 7b21e34f | 72 | bool weak_barriers, |
| 0a8a69dd | 73 | void *pages, |
| 46f9c2b9 | 74 | bool (*notify)(struct virtqueue *vq), |
| 9499f5e7 RR |
75 | void (*callback)(struct virtqueue *vq), |
| 76 | const char *name); | |
| 0a8a69dd | 77 | void vring_del_virtqueue(struct virtqueue *vq); |
| e34f8725 RR |
78 | /* Filter out transport-specific feature bits. */ |
| 79 | void vring_transport_features(struct virtio_device *vdev); | |
| 0a8a69dd RR |
80 | |
| 81 | irqreturn_t vring_interrupt(int irq, void *_vq); | |
| 0a8a69dd | 82 | #endif /* _LINUX_VIRTIO_RING_H */ |