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=-5.3 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,USER_AGENT_SANE_1 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 8FBEDC433E1 for ; Fri, 21 Aug 2020 12:10:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6A2BC20702 for ; Fri, 21 Aug 2020 12:10:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="ea9naKqr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727846AbgHUMKZ (ORCPT ); Fri, 21 Aug 2020 08:10:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727029AbgHUMKH (ORCPT ); Fri, 21 Aug 2020 08:10:07 -0400 Received: from mail-qk1-x741.google.com (mail-qk1-x741.google.com [IPv6:2607:f8b0:4864:20::741]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 12D89C061385 for ; Fri, 21 Aug 2020 05:10:06 -0700 (PDT) Received: by mail-qk1-x741.google.com with SMTP id i20so1108784qkk.8 for ; Fri, 21 Aug 2020 05:10:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chrisdown.name; s=google; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=x2zyWzSDJHBz/coWO6uLAm79U5a8FMGQOT/SueKdJ+Y=; b=ea9naKqr8k6EBi1A3g9ObPls+dIpoC6yWY0O5ZhiNNQKvgAEq+BFO0jgMfVfok0Zp1 dAfmV1ssdGlcRKHJWqrcwLRi4vS9IXcNpinOEIImI38Uz8VskffrqkXknzbZLIiRukJB Shwp7ebnq5cXh2dmzt9WCrQZOcXM7lTmVjZds= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:user-agent; bh=x2zyWzSDJHBz/coWO6uLAm79U5a8FMGQOT/SueKdJ+Y=; b=Dpoz2IXDJUdi01EPBvXJMVhlvFQRth5BUVfFO7PNKjJUycxHreMHSQdyySuR3s4gpk v04KGqEOzOubh63c5TyEVs4k2zetCdi2IfoDX7I7uOCKu7DAE+wX0XU45C45BEfkYcVI zkB6ID8SiHtIM+yxI9vlbVwOzX0orQj87kCw84vgKRZXlPqAasqaFYtrCqa4AEzVeBMQ jVTeeI0hMZIlm9Qp1mk2ta/uXC+7s4h+t4Uj6SYFD0XnF0mQ2seEPeOYZanDFSb/J5kq bJFBslrllKKTDRd8ddinpvHe4HvDs+Aouy6HKFGzmW+fI0fwMZS8/uk+13giBhA2GJM7 rrWQ== X-Gm-Message-State: AOAM532W+UFvwDeJmAajZ1VtzmvzPf/yOBgV3k1c3MI1RX5Agzg5o6AM SFvSsgY97c4867313cjOEk7HSSXU5cm6sEum X-Google-Smtp-Source: ABdhPJzb2TBqXJU8p75CDrXcgQvS4Tke5vC2h2StFVhvIaW1qRIU6238GpVOCetiZkdBYEESZT68XQ== X-Received: by 2002:a37:a797:: with SMTP id q145mr2232672qke.13.1598011805610; Fri, 21 Aug 2020 05:10:05 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:23fc]) by smtp.gmail.com with ESMTPSA id q4sm1527378qkm.78.2020.08.21.05.10.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Aug 2020 05:10:05 -0700 (PDT) Date: Fri, 21 Aug 2020 13:10:03 +0100 From: Chris Down To: linux-kernel@vger.kernel.org Cc: Borislav Petkov , Jakub Kicinski , Andrew Morton , kernel-team@fb.com, sean.j.christopherson@intel.com, tony.luck@intel.com, torvalds@linux-foundation.org, x86@kernel.org Subject: [PATCH v2 0/2] a couple of userspace MSR filtering improvements Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.14.6 (2020-07-11) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As discussed in Message-ID <20200714165621.GA3622@nazgul.tnic>. We all agree that userspace MSR twiddling is non-ideal, but we should be a bit cautious of taking up too much kmsg buffer if applications do repeated writes. `allow_writes=1` is possible, but is non-ideal (see patch 1 changelog). Also added pid information to the message, since it makes identification of the source (more or less) unambiguous. Changes in v2: - Fixed mostly aesthetic suggestions from Boris. Thanks! :-) Chris Down (2): x86: Prevent userspace MSR access from dominating the console x86: Make source of unrecognised MSR writes unambiguous arch/x86/kernel/msr.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) -- 2.28.0