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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125/* SPDX-License-Identifier: GPL-2.0 */#ifndef _LINUX_VIRTIO_RING_H#define _LINUX_VIRTIO_RING_H
#include <asm/barrier.h>#include <linux/virtio.h>#include <linux/irqreturn.h>#include <uapi/linux/virtio_ring.h>
/* * Barriers in virtio are tricky. Non-SMP virtio guests can't assume * they're not on an SMP host system, so they need to assume real * barriers. Non-SMP virtio hosts could skip the barriers, but does * anyone care? * * For virtio_pci on SMP, we don't need to order with respect to MMIO * accesses through relaxed memory I/O windows, so virt_mb() et al are * sufficient. * * For using virtio to talk to real devices (eg. other heterogeneous * CPUs) we do need real barriers. In theory, we could be using both * kinds of virtio, so it's a runtime decision, and the branch is * actually quite cheap. */
static inline void virtio_mb(bool weak_barriers){ if (weak_barriers) virt_mb(); else mb();}
static inline void virtio_rmb(bool weak_barriers){ if (weak_barriers) virt_rmb(); else dma_rmb();}
static inline void virtio_wmb(bool weak_barriers){ if (weak_barriers) virt_wmb(); else dma_wmb();}
#define virtio_store_mb(weak_barriers, p, v) \do { \ if (weak_barriers) { \ virt_store_mb(*p, v); \ } else { \ WRITE_ONCE(*p, v); \ mb(); \ } \} while (0) \
struct virtio_device;struct virtqueue;struct device;
/* * Creates a virtqueue and allocates the descriptor ring. If * may_reduce_num is set, then this may allocate a smaller ring than * expected. The caller should query virtqueue_get_vring_size to learn * the actual size of the ring. */struct virtqueue *vring_create_virtqueue(unsigned int index, unsigned int num, unsigned int vring_align, struct virtio_device *vdev, bool weak_barriers, bool may_reduce_num, bool ctx, bool (*notify)(struct virtqueue *vq), void (*callback)(struct virtqueue *vq), const char *name);
/* * Creates a virtqueue and allocates the descriptor ring with per * virtqueue mapping operations. */struct virtqueue *vring_create_virtqueue_map(unsigned int index, unsigned int num, unsigned int vring_align, struct virtio_device *vdev, bool weak_barriers, bool may_reduce_num, bool ctx, bool (*notify)(struct virtqueue *vq), void (*callback)(struct virtqueue *vq), const char *name, union virtio_map map);
/* * Creates a virtqueue with a standard layout but a caller-allocated * ring. */struct virtqueue *vring_new_virtqueue(unsigned int index, unsigned int num, unsigned int vring_align, struct virtio_device *vdev, bool weak_barriers, bool ctx, void *pages, bool (*notify)(struct virtqueue *vq), void (*callback)(struct virtqueue *vq), const char *name);
/* * Destroys a virtqueue. If created with vring_create_virtqueue, this * also frees the ring. */void vring_del_virtqueue(struct virtqueue *vq);
/* Filter out transport-specific feature bits. */void vring_transport_features(struct virtio_device *vdev);
irqreturn_t vring_interrupt(int irq, void *_vq);
u32 vring_notification_data(struct virtqueue *_vq);#endif /* _LINUX_VIRTIO_RING_H */