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=-4.1 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 23754C433E2 for ; Tue, 14 Jul 2020 15:47:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC64D2236F for ; Tue, 14 Jul 2020 15:47:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="POLxeDk+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727925AbgGNPra (ORCPT ); Tue, 14 Jul 2020 11:47:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37892 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726338AbgGNPra (ORCPT ); Tue, 14 Jul 2020 11:47:30 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 18418C061755 for ; Tue, 14 Jul 2020 08:47:30 -0700 (PDT) Received: from nazgul.tnic (77-85-108-148.ip.btc-net.bg [77.85.108.148]) (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 A0A701EC0344; Tue, 14 Jul 2020 17:47:26 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1594741646; 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=GYuwCWwzK+ziSG55zkdLFouJVnC8IgBoEQyI2gj6P44=; b=POLxeDk+OXvpF/ABe/kUqflUXRd9pZrkAXqFjTbyR28YPDutmFZP+tGHGEVYaO54asx1GA teljim4zuVfvnqBkWxSWE1k4fDpGKMX1E1NRwMflnJlx0PP4N3xlgo5R7XBUfkCKlmxT+f 4Pr88qaEHYTY4gZFSsk4rms5P6wa+BU= Date: Tue, 14 Jul 2020 17:47:28 +0200 From: Borislav Petkov To: Chris Down Cc: linux-kernel@vger.kernel.org, sean.j.christopherson@intel.com, tony.luck@intel.com, torvalds@linux-foundation.org, x86@kernel.org, kernel-team@fb.com Subject: Re: [PATCH -v2.1] x86/msr: Filter MSR writes Message-ID: <20200714154728.GA3101@nazgul.tnic> References: <20200615063837.GA14668@zn.tnic> <20200714121955.GA2080@chrisdown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200714121955.GA2080@chrisdown.name> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 14, 2020 at 01:19:55PM +0100, Chris Down wrote: > That is, even with pr_err_ratelimited, we still end up logging on basically > every single write, even though it's from the same TGID writing to the same > MSRs, and end up becoming >80% of kmsg. > > Of course, one can boot with `allow_writes=1` to avoid these messages at Yes, use that. >From a quick scan over that "tool" you pointed me at, it pokes at some MSRs from userspace which the kernel *also* writes to and this is exactly what should not be allowed. As to the "MSR hack", please describe what the issue is exactly so that we can get the proper people involved. If anything, this needs to be fixed in the kernel properly. If people are waiting for a year for a BIOS fix, I'd say there's a very slim chance for that to ever happen... Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette