[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Xen-devel] [PATCH SpectreV1+L1TF v4 03/11] config: introduce L1TF_LFENCE option
- To: Jan Beulich <JBeulich@xxxxxxxx>
- From: Julien Grall <julien.grall@xxxxxxx>
- Date: Wed, 23 Jan 2019 13:44:03 +0000
- Cc: Tim Deegan <tim@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Wei Liu <wei.liu2@xxxxxxxxxx>, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>, George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>, Dario Faggioli <dfaggioli@xxxxxxxx>, Martin Pohlack <mpohlack@xxxxxxxxx>, nmanthey@xxxxxxxxx, "Martin Mazein\(amazein\)" <amazein@xxxxxxxxx>, xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Julian Stecklina <jsteckli@xxxxxxxxx>, David Woodhouse <dwmw@xxxxxxxxxxxx>, Bjoern Doebel <doebel@xxxxxxxxx>
- Delivery-date: Wed, 23 Jan 2019 13:44:16 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
Hi Jan,
On 23/01/2019 13:39, Jan Beulich wrote:
On 23.01.19 at 14:24, <julien.grall@xxxxxxx> 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
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel
|
