[PATCH v2 1/2] xen/domain: Annotate struct domain as page aligned

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

struct domain is always a page aligned allocation.  Update it's type to
reflect this, so we can safely reuse the lower bits in the pointer for
auxiliary information.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Anthony PERARD <anthony.perard@xxxxxxxxxx>
CC: Michal Orzel <michal.orzel@xxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
CC: Julien Grall <julien@xxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Dario Faggioli <dfaggioli@xxxxxxxx>
CC: Juergen Gross <jgross@xxxxxxxx>
CC: George Dunlap <gwd@xxxxxxxxxxxxxx>

v2:
 * New

Interestingly this does cause two changes in the resulting binary, both caused
by GCC electing to use a more complicated addressing mode to save one ADD
instruction.
---
 xen/include/xen/sched.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 037c83fda219..8412b45178ca 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -645,7 +645,7 @@ struct domain
     unsigned int num_llc_colors;
     const unsigned int *llc_colors;
 #endif
-};
+} __aligned(PAGE_SIZE);
 
 static inline struct page_list_head *page_to_list(
     struct domain *d, const struct page_info *pg)
-- 
2.39.5