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linux-next/include/linux/virtio_byteorder.h
Greg Kurz 7d82410950 virtio: add explicit big-endian support to memory accessors
The current memory accessors logic is:
- little endian if little_endian
- native endian (i.e. no byteswap) if !little_endian

If we want to fully support cross-endian vhost, we also need to be
able to convert to big endian.

Instead of changing the little_endian argument to some 3-value enum, this
patch changes the logic to:
- little endian if little_endian
- big endian if !little_endian

The native endian case is handled by all users with a trivial helper. This
patch doesn't change any functionality, nor it does add overhead.

Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2015-06-01 15:48:54 +02:00

64 lines
1.4 KiB
C

#ifndef _LINUX_VIRTIO_BYTEORDER_H
#define _LINUX_VIRTIO_BYTEORDER_H
#include <linux/types.h>
#include <uapi/linux/virtio_types.h>
static inline bool virtio_legacy_is_little_endian(void)
{
#ifdef __LITTLE_ENDIAN
return true;
#else
return false;
#endif
}
static inline u16 __virtio16_to_cpu(bool little_endian, __virtio16 val)
{
if (little_endian)
return le16_to_cpu((__force __le16)val);
else
return be16_to_cpu((__force __be16)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)cpu_to_be16(val);
}
static inline u32 __virtio32_to_cpu(bool little_endian, __virtio32 val)
{
if (little_endian)
return le32_to_cpu((__force __le32)val);
else
return be32_to_cpu((__force __be32)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)cpu_to_be32(val);
}
static inline u64 __virtio64_to_cpu(bool little_endian, __virtio64 val)
{
if (little_endian)
return le64_to_cpu((__force __le64)val);
else
return be64_to_cpu((__force __be64)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)cpu_to_be64(val);
}
#endif /* _LINUX_VIRTIO_BYTEORDER */