Hi Jan,
On 23/01/2019 13:39, Jan Beulich wrote:
On 23.01.19 at 14:24, <julien.gr...@arm.com> wrote:
On 23/01/2019 11:51, Norbert Manthey wrote:
--- a/xen/include/xen/nospec.h
+++ b/xen/include/xen/nospec.h
@@ -68,10 +68,18 @@ static inline bool lfence_true(void) { return true; }
#endif
/*
- * protect evaluation of conditional with respect to speculation
+ * allow to protect evaluation of conditional with respect to speculation on
x86
*/
-#define evaluate_nospec(condition) \
+#if defined(CONFIG_L1TF_LFENCE_NONE) || !defined(CONFIG_X86)
+#define evaluate_nospec(condition) (condition)
+#elif defined(CONFIG_L1TF_LFENCE_BOTH)
+#define evaluate_nospec(condition) \
(((condition) && lfence_true()) || !lfence_true())
+#elif defined(CONFIG_L1TF_LFENCE_TRUE)
+#define evaluate_nospec(condition) ((condition) && lfence_true())
+#elif defined(CONFIG_L1TF_LFENCE_INTERMEDIATE)
+#define evaluate_nospec(condition) ({ bool res = (condition); rmb(); res; })
+#endif
None of the configs are defined on Arm, so can this be moved in arch-x86?
To be honest I'd like to avoid introducing asm/nospec.h for the time
being.
How about adding them in system.h as we did for array_index_mask_nospec?
Cheers,
--
Julien Grall
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