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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E74E8C00140 for ; Tue, 2 Aug 2022 10:52:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236536AbiHBKwH (ORCPT ); Tue, 2 Aug 2022 06:52:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57846 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233342AbiHBKwE (ORCPT ); Tue, 2 Aug 2022 06:52:04 -0400 Received: from mail-ej1-x636.google.com (mail-ej1-x636.google.com [IPv6:2a00:1450:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7DA2F17AAA for ; Tue, 2 Aug 2022 03:52:03 -0700 (PDT) Received: by mail-ej1-x636.google.com with SMTP id y13so11247417ejp.13 for ; Tue, 02 Aug 2022 03:52:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=XdVAnfQ0dVySFOaw/b8Pu8nKKQlmM6z22D0DLysEdi4=; b=mUJE4WwMaZAAOw98u9yYL3T1cfk1bqLWxU7Z4ZIhVTPU5vwJcAwYOdiILjPlQ9Vgrh 71OTJZHu+gxFgc5ws1qx59laygSiWwUq9yB1aKWrT9OcucBIkcGQcT1f7GExuQCu0Yl3 R1CVTk/KCJDCfhpTnWAmNmekPybUy4uv8U6QzD2hZR7w/rkUcPUkSlaz+mdIADu/4N2w gPDqkuTpFxcyE88koNDbj7ewQcdG73Nl5lJNii37i9sf1pVS2hrurHiGFJShZ9ZSWjP5 BlFnXkcblSRpb7LlWjIc1HVn0y6XNeNn9X5JESKkc9lgya+2zWpmcQOZYuTXeV36tv+F cNTw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=XdVAnfQ0dVySFOaw/b8Pu8nKKQlmM6z22D0DLysEdi4=; b=A3+GeWfWtK7K+R6JqSR7VbTuCWh7w8gA1SY5qXMNckPqgKi6WkMv2Nx1b89R/14dc2 ODqkOFXiLi/NW9qcGqygkwBHPVNKpkKW3KJU1kiXCntmLBA5KxRuCGGeBlsKNbGuBiiU n69KjB7iZa+IzMW2JmuAa0VIz36r9SQ+dF3Ol30MhWjRHt+JymY4P5WP4VHTMO5OSRYm SUGwF1k2AeIPIeq8Nujv5NoJdI77CVMqNwBXKSC6z82bhWaDC33M7iwrpf4WqBBe4rZJ WUrKaKtguZrczoHrK8kx2k1BGz3lGjINjjY26a6pXPx6pEaC6QzokSX/xtDl8FgdyNrA gHng== X-Gm-Message-State: AJIora+YzXQP0FmolaCrNbbO+HTwxnpAM3BHxCh6DjZHz37M2bTMxQqv dI4r19IkMTUrgQuizx42KWSCDIEiHF0= X-Google-Smtp-Source: AGRyM1vxcfWMK3q99cUVk0qLEqBAvD/2M3n1orppz+p3IWxotabALxtZBdc6dz7MOGC99xM+T/sR/g== X-Received: by 2002:a17:907:724c:b0:72e:e6fe:5ea4 with SMTP id ds12-20020a170907724c00b0072ee6fe5ea4mr16234439ejc.421.1659437522133; Tue, 02 Aug 2022 03:52:02 -0700 (PDT) Received: from gmail.com (84-236-113-167.pool.digikabel.hu. [84.236.113.167]) by smtp.gmail.com with ESMTPSA id f2-20020a17090631c200b00730860b6c43sm2193089ejf.173.2022.08.02.03.52.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Aug 2022 03:52:01 -0700 (PDT) Sender: Ingo Molnar Date: Tue, 2 Aug 2022 12:51:59 +0200 From: Ingo Molnar To: Chenyi Qiang Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Tony Luck , Fenghua Yu , linux-kernel@vger.kernel.org, x86@kernel.org Subject: Re: [RESEND] x86/bus_lock: Don't assume the init value of DEBUGCTLMSR.BUS_LOCK_DETECT to be zero Message-ID: References: <20220802033206.21333-1-chenyi.qiang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220802033206.21333-1-chenyi.qiang@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Chenyi Qiang wrote: > It's possible that BIOS/firmware has set DEBUGCTLMSR_BUS_LOCK_DETECT, or > this kernel has been kexec'd from a kernel that enabled bus lock > detection. > > Disable bus lock detection explicitly if not wanted. Makes sense. Just curious: in what circumstances does the BIOS/firmware set DEBUGCTLMSR_BUS_LOCK_DETECT? Does it use it, or does it enable it for some spurious reason, without really using the feature? (Assuming you are aware of instances where this happened - or was this simply a hypothetical?) Thanks, Ingo