xen/include: public: Document the padding in struct xen_hvm_param

There is an implicit padding of 2 bytes in struct xen_hvm_param between
the field domid and index. Make it explicit by introduce a padding
field. This can also serve as documentation.

Note that I don't think we can mandate it to be zero because a guest may
not have initialized the padding.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wl@xen.org>

diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index 610e020a626a53e46666949d77fa8c55ea770ac6..b599d3cbd0856988841fb8cc930e7d988166cb33 100644 (file)
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -32,6 +32,7 @@
 #define HVMOP_get_param           1
 struct xen_hvm_param {
     domid_t  domid;    /* IN */
+    uint16_t pad;
     uint32_t index;    /* IN */
     uint64_t value;    /* IN/OUT */
 };