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 959EBC43461 for ; Mon, 7 Sep 2020 11:30:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 47E1121741 for ; Mon, 7 Sep 2020 11:30:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="UuyGI6s5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729031AbgIGL3V (ORCPT ); Mon, 7 Sep 2020 07:29:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42590 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728942AbgIGLXA (ORCPT ); Mon, 7 Sep 2020 07:23:00 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 366E1C0617BE for ; Mon, 7 Sep 2020 04:12:17 -0700 (PDT) Received: from zn.tnic (p200300ec2f09090030eade31917bbe1c.dip0.t-ipconnect.de [IPv6:2003:ec:2f09:900:30ea:de31:917b:be1c]) (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 BB00B1EC0445; Mon, 7 Sep 2020 13:11:14 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1599477074; 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=cv5cgieD4imCKFHqyFVB5TEo45oyRkcNlpNdT0Kes4I=; b=UuyGI6s51Um5rVOmjTwZAduAmuq3+DLBrpOOlbC/Akq3EZwcgOCz+3ElExEWKzzRCGT0G+ mXDR8hNN16OyTBH1tzid1tIwbNpx/Bm0McKEx3Nc3a/+PD3BtkPOP9ciGPN8dJaDFextnH g8zNVqqhJ9sXATij9i8DVYDkdPvZJEs= Date: Mon, 7 Sep 2020 13:11:09 +0200 From: Borislav Petkov To: "Jason A. Donenfeld" Cc: Srinivas Pandruvada , kitsunyan , X86 ML , LKML Subject: Re: [PATCH] x86/msr: do not warn on writes to OC_MAILBOX Message-ID: <20200907111109.GB16029@zn.tnic> References: <20200907094843.1949-1-Jason@zx2c4.com> <20200907100647.GB10657@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 Hi, On Mon, Sep 07, 2020 at 12:46:35PM +0200, Jason A. Donenfeld wrote: > Are you sure that intel-undervolt using OC_MAILBOX from userspace is > actually a "misuse"? Should the kernel or kernel drivers actually be > involved with the task of underclocking? This seems pretty squarely in > the realm of "hobbyists poking and prodding at their CPUs" rather than > something made for a kernel driver, right? The only thing I'm sure is that *if* it makes sense for any driver to control something in the hardware over MSRs, it should *not* poke at naked MSRs but use a proper interface. I'd leave it to the people who actually need this interface, to explain why they do. > Also, what was the justification for whitelisting > MSR_IA32_ENERGY_PERF_BIAS? That's: tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c Once that thing gets converted to a proper interface too, that MSR goes off the allowlist too. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette