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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 76A33C433ED for ; Sun, 11 Apr 2021 16:03:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 47A5F6008E for ; Sun, 11 Apr 2021 16:03:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236350AbhDKQEE (ORCPT ); Sun, 11 Apr 2021 12:04:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235499AbhDKQED (ORCPT ); Sun, 11 Apr 2021 12:04:03 -0400 Received: from mail-ed1-x530.google.com (mail-ed1-x530.google.com [IPv6:2a00:1450:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6561EC061574 for ; Sun, 11 Apr 2021 09:03:46 -0700 (PDT) Received: by mail-ed1-x530.google.com with SMTP id f8so12102282edd.11 for ; Sun, 11 Apr 2021 09:03:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amacapital-net.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=vfZgknz44RIyZV3OVgESHFCGGox2VIjLnfpUwRDEyZo=; b=lENuuVkia+zCtsiN5M4UDbuZ7xT82SJhX8Gzr8ikzg3mbjOzmi33Dj+a+Ior9aydzb z+UDibHBQvtY9zxknDNFvzsvddutYbaMnObHNHCiC2UVepDSx6OqxBj5V91PMSW5L5Vo ug/CuU97cmc+LmQuXnrNThLNSlcAhcuL0ZYHp9gFoCAxKnHlO2hqIfqPp/AhEuyNfM7+ Qc5hugNZxs2Dna5KhRat5jmFG9cM7f/U7G0OlYYsx5OgCm702dtkPe/DMINLACPrL5SN EVJ/V4kmnOJ1uK2ZZ6dhupoKZL0uvA1Rjn5wxkumeBHI5g1TS/a/x5CUUCfnMNQ5azis EDIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=vfZgknz44RIyZV3OVgESHFCGGox2VIjLnfpUwRDEyZo=; b=RE03Y6DuIl5SEV8O3brMwGiVaDUhH38aH0ZXdTe20+ok12zG6kzm5E7nAoRufBxZNH tGpJyQYEbXe0D+sTzp5pA+Nt+NoA4cXOXG+vCcSfpnwXTil+RpoMrriHnyvqEmR2wqpi dYRBZQDhKc4AnOHHlRrl+RVCCVtZJ838VXt5Uqou1eywgrOvtN53ngpBP+aYrFTYtkPI ValBij+niXEYOsQ1xaF6BQaxI2u/ViLHKm0ocljpJJEVDBZHp0i90YoxSD2dwbgdfX1r yQGA70UAcgu6cq4bB+UeoaM0P2z3ifL8x0OCfrTIbhTkVTY3BBcrue0HrAR/EqK6Vxod TnIg== X-Gm-Message-State: AOAM533fxQPCOgxbVbvgXypKuCkKsQVBGcVOr8/xFjd7+Tv652mCe2kd 6C59bB6YqgdnWAOZFeDNgM1emnxJS3ZOKatu+xGmNw== X-Google-Smtp-Source: ABdhPJxGU5PHqWYzSWtsm+8wSY6EVho5MZGQGfCoW6t53C/1lV6GRoE6mvIo90ozLfVFGdEeSuvt6KO94toLP3j4kIY= X-Received: by 2002:a05:6402:27ce:: with SMTP id c14mr25798056ede.263.1618157025138; Sun, 11 Apr 2021 09:03:45 -0700 (PDT) MIME-Version: 1.0 References: <1617092747-15769-1-git-send-email-feng.tang@intel.com> <87y2dq32xc.ffs@nanos.tec.linutronix.de> <20210410094752.GB21691@zn.tnic> <20210410121144.GC21691@zn.tnic> <87r1jiug4e.fsf@linux.intel.com> In-Reply-To: <87r1jiug4e.fsf@linux.intel.com> From: Andy Lutomirski Date: Sun, 11 Apr 2021 09:03:34 -0700 Message-ID: Subject: Re: [PATCH] x86/msr: Block writes to certain MSRs unconditionally To: Andi Kleen Cc: Borislav Petkov , Thomas Gleixner , Feng Tang , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra , X86 ML , LKML , "Zhang, Rui" , "Kleen, Andi" , Dave Hansen , Len Brown Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 10, 2021 at 11:52 AM Andi Kleen wrote: > > Borislav Petkov writes: > > > From: Borislav Petkov > > Date: Sat, 10 Apr 2021 14:08:13 +0200 > > > > There are a bunch of MSRs which luserspace has no business poking at, > > whatsoever. Add a ban list and put the TSC-related MSRs in there. Issue > > a big juicy splat to catch offenders. > > Have you ever seen any user programs actually write those MSRs? > I don't see why they ever would, it's not that they have any motivation > to do it (unlike SMM), and I don't know of any examples. I have actually seen real user programs poke MSR_SYSCALL_MASK.