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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 B9A9EC433E0 for ; Tue, 9 Jun 2020 17:43:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9BB75207F9 for ; Tue, 9 Jun 2020 17:43:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731902AbgFIRng (ORCPT ); Tue, 9 Jun 2020 13:43:36 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56073 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728472AbgFIRng (ORCPT ); Tue, 9 Jun 2020 13:43:36 -0400 Received: from 1.general.cascardo.us.vpn ([10.172.70.58] helo=localhost.localdomain) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1jiiHe-0004lb-1P; Tue, 09 Jun 2020 17:43:34 +0000 From: Thadeu Lima de Souza Cascardo To: linux-kernel@vger.kernel.org Cc: Mark Gross , x86@kernel.org, "H. Peter Anvin" , Borislav Petkov , Ingo Molnar , Thomas Gleixner , Thadeu Lima de Souza Cascardo , John Johansen , Steve Beattie Subject: [PATCH] x86/speculation/srbds: do not try to turn mitigation off when not supported Date: Tue, 9 Jun 2020 14:43:13 -0300 Message-Id: <20200609174313.2600320-1-cascardo@canonical.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When SRBDS is mitigated by TSX OFF, update_srbds_msr will still read and write to MSR_IA32_MCU_OPT_CTRL even when that is not supported by the microcode. Checking for X86_FEATURE_SRBDS_CTRL as a CPU feature available makes more sense than checking for SRBDS_MITIGATION_UCODE_NEEDED as the found "mitigation". Signed-off-by: Thadeu Lima de Souza Cascardo Acked-by: John Johansen Acked-by: Steve Beattie Cc: stable@vger.kernel.org --- arch/x86/kernel/cpu/bugs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index b6f887be440c..ee5bdca7fd30 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -432,7 +432,7 @@ void update_srbds_msr(void) if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) return; - if (srbds_mitigation == SRBDS_MITIGATION_UCODE_NEEDED) + if (!boot_cpu_has(X86_FEATURE_SRBDS_CTRL)) return; rdmsrl(MSR_IA32_MCU_OPT_CTRL, mcu_ctrl); -- 2.25.1