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authorMichael S. Tsirkin <mst@redhat.com>2014-10-22 15:35:56 +0300
committerMichael S. Tsirkin <mst@redhat.com>2014-12-09 12:05:24 +0200
commiteef960a04354d13426c43a4e3750a5e2b383040c (patch)
treea5d6e327dbb22c85b2f6592077a544bcc0153471 /include/linux/virtio_byteorder.h
parent4ec22faeb2a165b6ce7009f91309046010b3f282 (diff)
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 <mst@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Diffstat (limited to 'include/linux/virtio_byteorder.h')
-rw-r--r--include/linux/virtio_byteorder.h59
1 files changed, 59 insertions, 0 deletions
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 <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 */