Hi Michael,
On 10/22/2014 11:50 AM, Michael S. Tsirkin wrote:
> 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 will (in the
> future) query device endian-ness and act accordingly.
>
> At the moment, stub them out and assume native endian-ness everywhere.
>
> Signed-off-by: Michael S. Tsirkin <[email protected]>
> ---
> include/linux/virtio_config.h | 16 +++++++++++++
> include/uapi/linux/virtio_ring.h | 49
> ++++++++++++++++++++--------------------
> include/uapi/linux/Kbuild | 1 +
> 3 files changed, 42 insertions(+), 24 deletions(-)
>
> diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> index 7f4ef66..d38d3c2 100644
> --- a/include/linux/virtio_config.h
> +++ b/include/linux/virtio_config.h
> @@ -4,6 +4,7 @@
> #include <linux/err.h>
> #include <linux/bug.h>
> #include <linux/virtio.h>
> +#include <linux/virtio_byteorder.h>
What patch creates this file?
> #include <uapi/linux/virtio_config.h>
>
> /**
> @@ -152,6 +153,21 @@ int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
> return 0;
> }
>
> +/* Memory accessors */
> +#define DEFINE_VIRTIO_XX_TO_CPU(bits) \
> +static inline u##bits virtio##bits##_to_cpu(struct virtio_device *vdev,
> __virtio##bits val) \
> +{ \
> + return __virtio##bits##_to_cpu(false, val); \
> +} \
> +static inline __virtio##bits cpu_to_virtio##bits(struct virtio_device *vdev,
> u##bits val) \
> +{ \
> + return __cpu_to_virtio##bits(false, val); \
> +}
> +
> +DEFINE_VIRTIO_XX_TO_CPU(16)
> +DEFINE_VIRTIO_XX_TO_CPU(32)
> +DEFINE_VIRTIO_XX_TO_CPU(64)
> +
> /* Config space accessors. */
> #define virtio_cread(vdev, structname, member, ptr) \
> do { \
> diff --git a/include/uapi/linux/virtio_ring.h
> b/include/uapi/linux/virtio_ring.h
> index a99f9b7..6c00632 100644
> --- a/include/uapi/linux/virtio_ring.h
> +++ b/include/uapi/linux/virtio_ring.h
> @@ -32,6 +32,7 @@
> *
> * Copyright Rusty Russell IBM Corporation 2007. */
> #include <linux/types.h>
> +#include <linux/virtio_types.h>
>
> /* This marks a buffer as continuing via the next field. */
> #define VRING_DESC_F_NEXT 1
> @@ -61,32 +62,32 @@
> /* Virtio ring descriptors: 16 bytes. These can chain together via "next".
> */
> struct vring_desc {
> /* Address (guest-physical). */
> - __u64 addr;
> + __virtio64 addr;
> /* Length. */
> - __u32 len;
> + __virtio32 len;
> /* The flags as indicated above. */
> - __u16 flags;
> + __virtio16 flags;
> /* We chain unused descriptors via this, too */
> - __u16 next;
> + __virtio16 next;
> };
How does __virtio64 differ from __le64?
Thanks,
Chris
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