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=-3.9 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 3F272C43461 for ; Tue, 8 Sep 2020 18:02:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C3F652074D for ; Tue, 8 Sep 2020 18:02:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="ls4q+gxq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732157AbgIHSCh (ORCPT ); Tue, 8 Sep 2020 14:02:37 -0400 Received: from mail.skyhub.de ([5.9.137.197]:38970 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731663AbgIHSBS (ORCPT ); Tue, 8 Sep 2020 14:01:18 -0400 Received: from zn.tnic (p200300ec2f10bf0059bdf9fa8e813382.dip0.t-ipconnect.de [IPv6:2003:ec:2f10:bf00:59bd:f9fa:8e81:3382]) (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 3C9511EC0489; Tue, 8 Sep 2020 20:01:17 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1599588077; 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=72WG1McxFqIGqR0+XMVCYnaTg8/Pu4r+S87nI13px98=; b=ls4q+gxq01ufyfWCGaDIr4cX0hDa7QQPPRNqrHWOp9VTyGguOSzHrsGSotlWrzuk+CGZSV jte8+0fkjQm1FsAfuFrt0UUtL9edHhcws3KnwZDKIplufTwJYPvkwwvLyNm59pc4yax0aq O6Ogqmuru1rmAYWqsFZHp9hSMNGeyDQ= Date: Tue, 8 Sep 2020 20:01:12 +0200 From: Borislav Petkov To: "Jason A. Donenfeld" Cc: Srinivas Pandruvada , kitsunyan , "Brown, Len" , X86 ML , LKML , Linus Torvalds , Sultan Alsawaf Subject: Re: [PATCH] x86/msr: do not warn on writes to OC_MAILBOX Message-ID: <20200908180112.GK25236@zn.tnic> References: <20200907094843.1949-1-Jason@zx2c4.com> <20200907100647.GB10657@zn.tnic> <22617e57e541e460fac09db04fdb370f8e96e8ef.camel@linux.intel.com> <20200908172558.GG25236@zn.tnic> <20200908173656.GI25236@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 08, 2020 at 07:42:12PM +0200, Jason A. Donenfeld wrote: > Are you prepared to track down all the MSRs that might maybe do > something naughty? I'm not prepared - that's why this MSR filtering. To block *all* direct MSR accesses from userspace in the future. > Does `dd` warn when you run `dd if=/dev/zero of=/dev/sda`? Yah, because that's the same as bricking your hardware. Geez. > Probably not possible. Optimal values are related to the "silicon > lottery" that occurs when you buy a new CPU. Different optimal values > for different individual chips. Let's wait for what Srinivas finds out. I'd let Intel decide what they wanna do. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette