[Qemu-devel] [PATCH v2 1/3] memory: Align MemoryRegionSections fields

["Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

MemoryRegionSection includes an Int128 'size' field;
on some platforms the compiler causes an alignment of this to
a 128bit boundary, leaving 8 bytes of dead space.
This deadspace can be filled with junk.

Move the size field to the top avoiding unnecessary alignment.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 include/exec/memory.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 606250172a..a74a58c289 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -487,10 +487,10 @@ static inline FlatView *address_space_to_flatview(AddressSpace *as)
  * @nonvolatile: this section is non-volatile
  */
 struct MemoryRegionSection {
+    Int128 size;
     MemoryRegion *mr;
     FlatView *fv;
     hwaddr offset_within_region;
-    Int128 size;
     hwaddr offset_within_address_space;
     bool readonly;
     bool nonvolatile;
-- 
2.21.0