[PATCH v4 for-4.14 1/2] pvcalls: Clearly spell out that the header is just a reference

[Julien Grall <julien@xxxxxxx>]

From: Julien Grall <jgrall@xxxxxxxxxx>

A recent thread on xen-devel [1] pointed out that the header was
provided as a reference for the specification.

Unfortunately, this was never written down in xen.git so for an external
user (or a reviewer) it is not clear whether the spec or the header
shoudl be followed when there is a conflict.

To avoid more confusion, a paragraph is added at the top of the header
to clearly spell out it is only provided for reference.

[1] 
https://lore.kernel.org/xen-devel/alpine.DEB.2.21.2006151343430.9074@sstabellini-ThinkPad-T480s/

Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>

---
    Changes in v4:
        - New patch
---
 xen/include/public/io/pvcalls.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/xen/include/public/io/pvcalls.h b/xen/include/public/io/pvcalls.h
index cb8171275c13..905880735dda 100644
--- a/xen/include/public/io/pvcalls.h
+++ b/xen/include/public/io/pvcalls.h
@@ -3,6 +3,9 @@
  *
  * Refer to docs/misc/pvcalls.markdown for the specification
  *
+ * The header is provided as a C reference for the specification. In
+ * case of conflict, the specification is authoritative.
+ *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to
  * deal in the Software without restriction, including without limitation the
-- 
2.17.1