1. 根目录:
2. include
3. linux
4. virtio_byteorder.h

#ifndef _LINUX_VIRTIO_BYTEORDER_H
#define _LINUX_VIRTIO_BYTEORDER_H
#include <linux/types.h>
#include <uapi/linux/virtio_types.h>

/*
 * Low-level memory accessors for handling virtio in modern little endian and in
 * compatibility native endian format.
 */

static inline u16 __virtio16_to_cpu(bool little_endian, __virtio16 val)
{
	if (little_endian)
		return le16_to_cpu((__force __le16)val);
	else
		return (__force u16)val;
}

static inline __virtio16 __cpu_to_virtio16(bool little_endian, u16 val)
{
	if (little_endian)
		return (__force __virtio16)cpu_to_le16(val);
	else
		return (__force __virtio16)val;
}

static inline u32 __virtio32_to_cpu(bool little_endian, __virtio32 val)
{
	if (little_endian)
		return le32_to_cpu((__force __le32)val);
	else
		return (__force u32)val;
}

static inline __virtio32 __cpu_to_virtio32(bool little_endian, u32 val)
{
	if (little_endian)
		return (__force __virtio32)cpu_to_le32(val);
	else
		return (__force __virtio32)val;
}

static inline u64 __virtio64_to_cpu(bool little_endian, __virtio64 val)
{
	if (little_endian)
		return le64_to_cpu((__force __le64)val);
	else
		return (__force u64)val;
}

static inline __virtio64 __cpu_to_virtio64(bool little_endian, u64 val)
{
	if (little_endian)
		return (__force __virtio64)cpu_to_le64(val);
	else
		return (__force __virtio64)val;
}

#endif /* _LINUX_VIRTIO_BYTEORDER */