Adding Q suffixes to FXSAVE/FXRSTOR did break the 32-bit build. Don't go
back though, as the hand-coded 0x48 there weren't quite right either for
the 32-bit case (they might well cause confusion when looking at the
disassembly). Instead arrange for the compiler to DCE respective asm()-s,
by short-circuiting REX_* to zero.
Fixes: 5a33ea2800c1 ("x86emul: drop open-coding of REX.W prefixes")
Signed-off-by: Jan Beulich <jbeul...@suse.com>
--- a/xen/arch/x86/x86_emulate/private.h
+++ b/xen/arch/x86/x86_emulate/private.h
@@ -110,11 +110,19 @@ struct operand {
} mem;
};
+#if defined(__x86_64__)
#define REX_PREFIX 0x40
#define REX_B 0x01
#define REX_X 0x02
#define REX_R 0x04
#define REX_W 0x08
+#elif defined(__i386__)
+#define REX_PREFIX 0
+#define REX_B 0
+#define REX_X 0
+#define REX_R 0
+#define REX_W 0
+#endif
enum simd_opsize {
simd_none,
