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virtio: memory access APIs

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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 <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
This commit is contained in:
Michael S. Tsirkin
2014-10-22 15:35:56 +03:00
parent 4ec22faeb2
commit eef960a043
5 changed files with 161 additions and 22 deletions
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32
include/linux/virtio_config.h
View File

@@ -4,6 +4,7 @@
#include <linux/err.h>
#include <linux/bug.h>
#include <linux/virtio.h>
#include <linux/virtio_byteorder.h>
#include <uapi/linux/virtio_config.h>
/**
@@ -199,6 +200,37 @@ int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
return 0;
}
/* Memory accessors */
static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
{
return __virtio16_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}
static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
{
return __cpu_to_virtio16(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}
static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
{
return __virtio32_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}
static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
{
return __cpu_to_virtio32(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}
static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
{
return __virtio64_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}
static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
{
return __cpu_to_virtio64(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
}
/* Config space accessors. */
#define virtio_cread(vdev, structname, member, ptr) \
do { \