From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linutronix.de (146.0.238.70:993) by crypto-ml.lab.linutronix.de with IMAP4-SSL for ; 14 Nov 2018 04:04:35 -0000 Received: from mga18.intel.com ([134.134.136.126]) by Galois.linutronix.de with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1gMmPp-0003tj-FX for speck@linutronix.de; Wed, 14 Nov 2018 05:04:34 +0100 Date: Tue, 13 Nov 2018 20:04:29 -0800 From: Andi Kleen Subject: [MODERATED] Re: [PATCH 2/4] RFC-MDSv1 0 Message-ID: <20181114040429.GL6218@tassilo.jf.intel.com> References: <20181113013545.GI6218@tassilo.jf.intel.com> <6c12a339-278c-3896-b423-f03a25ec8ace@citrix.com> MIME-Version: 1.0 In-Reply-To: <6c12a339-278c-3896-b423-f03a25ec8ace@citrix.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit To: speck@linutronix.de List-ID: > I was under the impression that the recommendation to use a NUL selector > was specifically to avoid this second read. No the rationale for the recommendation is to avoid mispredictions in the microcode. But the two are equivalent. -Andi