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=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 574BBC433E2 for ; Tue, 14 Jul 2020 19:18:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2C1B02242C for ; Tue, 14 Jul 2020 19:18:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="IzZThgcP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729375AbgGNTSD (ORCPT ); Tue, 14 Jul 2020 15:18:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728370AbgGNTSC (ORCPT ); Tue, 14 Jul 2020 15:18:02 -0400 Received: from mail-io1-xd32.google.com (mail-io1-xd32.google.com [IPv6:2607:f8b0:4864:20::d32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 64622C061755 for ; Tue, 14 Jul 2020 12:18:02 -0700 (PDT) Received: by mail-io1-xd32.google.com with SMTP id e64so18516576iof.12 for ; Tue, 14 Jul 2020 12:18:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=O+ls3I/N5zsUDO1aedELyDp7Kj09Qsqb8dgbqg/A980=; b=IzZThgcPgwciiCyVEcQUJ/jfFCpEk/2MHNYLhGkXYrsI6T2S8YEvqn5hytvliX0W+a U7XZBozq1quYR/PnHj+En8JweGapYod2EjFhYop3iQeptqiKwVZaNeAE8n7jGZHJcvi3 i3JGBvvQYa93bVF4ZKKbvhP+oEPqsJPa/kDdn718wyLjxL5hwY8Cyc/ANYx83mLLq3Kt hahpKBGipauXvaLE91+i7Sfd6BSBkQbSqBonxcodbI5jBjAVj7m7zoOG8fvSd2fBd2Ig nVvOebWetUGEnnommtlkzG0peh1QODDmBQszhuzATE44PAl30vckla5GrFIcRciKPwUz Yb6A== 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=O+ls3I/N5zsUDO1aedELyDp7Kj09Qsqb8dgbqg/A980=; b=bbJLMeZYe0UG2GkjyspiZ1YwDTHpTWxU1wSwfhw28LHCTN5mrNcFRGosOAF2j1DuOH tipOkaFvkX5gSgy/eIWE2E64dJ9+z7oKroj+7WmGfAsbssBF/InCJAA/fniy3oQVPvsr eqlTsCJ3lklvWGCrhd9ZrqpNkpv60Fn+Z6W+dOkH+aeHAtxUP+iuT9Wa96mTMsRJiWZo GZKfB1on49F8iKPqYc1t7C9ytZfKJBfuPIJ7LXtMKbOYWOPaFiuPvGGGjzdeY12RfBDh C85bsgfO1vUHeeEeHs4Ak9TVd9Vni+xq/Q1lzg5Dhr7BtjUP6rtW8ymPi6sJcpfm+e+y 3/vw== X-Gm-Message-State: AOAM530h19DKfeC1Bp5O4xasGYYID2zx+JBqB3cYA57hbr9rYVjk4YDx KP0bCOe26q3iBtOwBY16GJTI11Mt3f/G16rJzbglqQ== X-Google-Smtp-Source: ABdhPJzbujNqtoQoRYwDGoiM7cW9ZxY92ueoJ7abo6SGFJr01p4gHzSMuSZlOFme+LCpUveW0ZKh0vQSSFndz7J0gTc= X-Received: by 2002:a6b:6508:: with SMTP id z8mr6459683iob.82.1594754281290; Tue, 14 Jul 2020 12:18:01 -0700 (PDT) MIME-Version: 1.0 References: <20200615063837.GA14668@zn.tnic> <20200714121955.GA2080@chrisdown.name> <20200714154728.GA3101@nazgul.tnic> <20200714160448.GC2080@chrisdown.name> In-Reply-To: <20200714160448.GC2080@chrisdown.name> From: Matthew Garrett Date: Tue, 14 Jul 2020 12:17:50 -0700 Message-ID: Subject: Re: [PATCH -v2.1] x86/msr: Filter MSR writes To: Chris Down Cc: Borislav Petkov , Linux Kernel Mailing List , sean.j.christopherson@intel.com, tony.luck@intel.com, Linus Torvalds , "the arch/x86 maintainers" , kernel-team@fb.com Content-Type: text/plain; charset="UTF-8" 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 9:04 AM Chris Down wrote: > Either way, again, this isn't really the point. :-) The point is that there > _are_ currently widespread cases involving poking MSRs from userspace, however > sacrilegious or ugly (which I agree with!), and while people should be told > about that, it's excessive to have the potential to take up 80% of kmsg in the > default configuration. It doesn't take thousands of messages to get the message > across, that's what a custom printk ratelimit is for. Agreed - we should now offer all the necessary interfaces to avoid userspace having to hit MSRs directly for thermal management, but that wasn't always the case, and as a result there's tooling that still behaves this way.