xref: /kernel/linux/patches/linux-4.19/prebuilts/usr/include/linux/virtio_ring.h

/*
 * This header was generated from the Linux kernel headers by update_headers.py,
 * to provide necessary information from kernel to userspace, such as constants,
 * structures, and macros, and thus, contains no copyrightable information.
 */
#ifndef _UAPI_LINUX_VIRTIO_RING_H
#define _UAPI_LINUX_VIRTIO_RING_H
#ifndef __KERNEL__
#include <stdint.h>
#endif
#include <linux/types.h>
#include <linux/virtio_types.h>
#define VRING_DESC_F_NEXT	1
#define VRING_DESC_F_WRITE	2
#define VRING_DESC_F_INDIRECT	4
#define VRING_USED_F_NO_NOTIFY	1
#define VRING_AVAIL_F_NO_INTERRUPT	1
#define VIRTIO_RING_F_INDIRECT_DESC	28
#define VIRTIO_RING_F_EVENT_IDX		29
struct vring_desc {

	__virtio64 addr;

	__virtio32 len;

	__virtio16 flags;

	__virtio16 next;
};
struct vring_avail {
	__virtio16 flags;
	__virtio16 idx;
	__virtio16 ring[];
};
struct vring_used_elem {

	__virtio32 id;

	__virtio32 len;
};
struct vring_used {
	__virtio16 flags;
	__virtio16 idx;
	struct vring_used_elem ring[];
};
struct vring {
	unsigned int num;
	struct vring_desc *desc;
	struct vring_avail *avail;
	struct vring_used *used;
};
#define VRING_AVAIL_ALIGN_SIZE 2
#define VRING_USED_ALIGN_SIZE 4
#define VRING_DESC_ALIGN_SIZE 16
#define vring_used_event(vr) ((vr)->avail->ring[(vr)->num])
#define vring_avail_event(vr) (*(__virtio16 *)&(vr)->used->ring[(vr)->num])
static inline void vring_init(struct vring *vr, unsigned int num, void *p,
			      unsigned long align)
{
	vr->num = num;
	vr->desc = p;
	vr->avail = p + num*sizeof(struct vring_desc);
	vr->used = (void *)(((uintptr_t)&vr->avail->ring[num] + sizeof(__virtio16)
		+ align-1) & ~(align - 1));
}
static inline unsigned vring_size(unsigned int num, unsigned long align)
{
	return ((sizeof(struct vring_desc) * num + sizeof(__virtio16) * (3 + num)
		 + align - 1) & ~(align - 1))
		+ sizeof(__virtio16) * 3 + sizeof(struct vring_used_elem) * num;
}
static inline int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old)
{

	return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old);
}
#endif