From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0146C04AB4 for ; Thu, 16 May 2019 16:01:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7D2FA20833 for ; Thu, 16 May 2019 16:01:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727380AbfEPQBr (ORCPT ); Thu, 16 May 2019 12:01:47 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:42888 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727025AbfEPP6q (ORCPT ); Thu, 16 May 2019 11:58:46 -0400 Received: from [167.98.27.226] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hRImJ-0006zQ-Ge; Thu, 16 May 2019 16:58:43 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hRImF-0001St-57; Thu, 16 May 2019 16:58:39 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Thomas Gleixner" , "Josh Poimboeuf" Date: Thu, 16 May 2019 16:55:33 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 81/86] x86/speculation/mds: Add 'mitigations=' support for MDS In-Reply-To: X-SA-Exim-Connect-IP: 167.98.27.226 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.68-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Josh Poimboeuf commit 5c14068f87d04adc73ba3f41c2a303d3c3d1fa12 upstream. Add MDS to the new 'mitigations=' cmdline option. Signed-off-by: Josh Poimboeuf Signed-off-by: Thomas Gleixner [bwh: Backported to 3.16: - Drop the auto,nosmt option, which we can't support - Adjust filenames, context] Signed-off-by: Ben Hutchings --- --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1920,6 +1920,7 @@ bytes respectively. Such letter suffixes nospectre_v2 [X86] spectre_v2_user=off [X86] spec_store_bypass_disable=off [X86] + mds=off [X86] auto (default) Mitigate all CPU vulnerabilities, but leave SMT --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -287,7 +287,7 @@ static const char * const mds_strings[] static void __init mds_select_mitigation(void) { - if (!boot_cpu_has_bug(X86_BUG_MDS)) { + if (!boot_cpu_has_bug(X86_BUG_MDS) || cpu_mitigations_off()) { mds_mitigation = MDS_MITIGATION_OFF; return; }