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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 55EE2C433ED for ; Sat, 10 Apr 2021 09:48:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 20971610C8 for ; Sat, 10 Apr 2021 09:48:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234506AbhDJJsN (ORCPT ); Sat, 10 Apr 2021 05:48:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229591AbhDJJsL (ORCPT ); Sat, 10 Apr 2021 05:48:11 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E9EBC061762 for ; Sat, 10 Apr 2021 02:47:57 -0700 (PDT) Received: from zn.tnic (p200300ec2f1aea004ff424aef8172112.dip0.t-ipconnect.de [IPv6:2003:ec:2f1a:ea00:4ff4:24ae:f817:2112]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 39E911EC0409; Sat, 10 Apr 2021 11:47:54 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1618048074; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=Tvf19OXUBXZlFKKnhTg3hQs3cfovqzCzgW+ka1x1V7A=; b=RtQILUdppQ3HWLrs1+lEOkyhYze2Gu6mUYmik1O3u8SXLUOecirHFe2r4o8IFrxeVMJ7HX ZCZgc0imZOjkRL8glZ2uTGJuiuq6XXnJ9PUO6LyzG5fouE9k0fjf72ONo6SyXTY4buPcrb IXXLv0qXb79VKueBdnsZgrG9ePl0wTQ= Date: Sat, 10 Apr 2021 11:47:52 +0200 From: Borislav Petkov To: Thomas Gleixner Cc: Feng Tang , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra , x86@kernel.org, linux-kernel@vger.kernel.org, rui.zhang@intel.com, andi.kleen@intel.com, dave.hansen@intel.com, len.brown@intel.com Subject: Re: [RFC 1/2] x86/tsc: add a timer to make sure tsc_adjust is always checked Message-ID: <20210410094752.GB21691@zn.tnic> References: <1617092747-15769-1-git-send-email-feng.tang@intel.com> <87y2dq32xc.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <87y2dq32xc.ffs@nanos.tec.linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 10, 2021 at 11:27:11AM +0200, Thomas Gleixner wrote: > On Tue, Mar 30 2021 at 16:25, Feng Tang wrote: > > Normally the tsc_sync will be checked every time system enters idle state, > > but there is still caveat that a system won't enter idle, either because > > it's too busy or configured purposely to not enter idle. Setup a periodic > > timer to make sure the check is always on. > > Bah. I really hate the fact that we don't have a knob to disable writes > to the TSC/TSC_ADJUST msrs. That would spare this business alltogether. We have the MSR filtering and I'd *love* to add those MSRs to a permanent ban list of MSRs which will never ever be written to from luserspace. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette