From eef960a04354d13426c43a4e3750a5e2b383040c Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Wed, 22 Oct 2014 15:35:56 +0300 Subject: virtio: memory access APIs virtio 1.0 makes all memory structures LE, so we need APIs to conditionally do a byteswap on BE architectures. To make it easier to check code statically, add virtio specific types for multi-byte integers in memory. Add low level wrappers that do a byteswap conditionally, these will be useful e.g. for vhost. Add high level wrappers that query device endian-ness and act accordingly. Signed-off-by: Michael S. Tsirkin Reviewed-by: Cornelia Huck --- include/linux/virtio_byteorder.h | 59 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 include/linux/virtio_byteorder.h (limited to 'include/linux/virtio_byteorder.h') diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h new file mode 100644 index 000000000000..51865d05b267 --- /dev/null +++ b/include/linux/virtio_byteorder.h @@ -0,0 +1,59 @@ +#ifndef _LINUX_VIRTIO_BYTEORDER_H +#define _LINUX_VIRTIO_BYTEORDER_H +#include +#include + +/* + * 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 */ -- cgit v1.2.3