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=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, 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 59CE8C5ACAE for ; Thu, 12 Sep 2019 10:19:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3045920830 for ; Thu, 12 Sep 2019 10:19:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=shutemov-name.20150623.gappssmtp.com header.i=@shutemov-name.20150623.gappssmtp.com header.b="DZxZImvW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731296AbfILKTS (ORCPT ); Thu, 12 Sep 2019 06:19:18 -0400 Received: from mail-ed1-f65.google.com ([209.85.208.65]:43329 "EHLO mail-ed1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730909AbfILKTS (ORCPT ); Thu, 12 Sep 2019 06:19:18 -0400 Received: by mail-ed1-f65.google.com with SMTP id c19so23399997edy.10 for ; Thu, 12 Sep 2019 03:19:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=rCJRuZodeCpPu+MIWRS27Ed/gzyJWJ/AkAs4o6Nd360=; b=DZxZImvWh3/RaN4AE3pN9IM+EaDq95bEB9WKbkEUjtsK68dv6CAittKvOAjmVXq1uS 0OZ3gtdUzDlb0Yr4tN+3XTchD0LNxJmcHw+aFBqDAl5XwtAybbIeSXgK8m78mU1PBxTw RQ1W9kHzXirW6bxcfLufD4asM8wXrxRbXacABxnXNZx2YRPCi1bzPC+/2YDgiCPB33Mj IZo2CGwdJ5+jAhn6EiNPcahRC07NDk9cZdKOt+rQ+p/x/flkFP3Udw6kaQzWShttlEDy 6na3vsWlZYukZ/+8JnNgpnI6xpUypqml0rexPDn4IuxD9l2mNZffU6ImTZw6LRIDHOBF 2+qQ== 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:references :mime-version:content-disposition:in-reply-to:user-agent; bh=rCJRuZodeCpPu+MIWRS27Ed/gzyJWJ/AkAs4o6Nd360=; b=L0uYRLxytt9+u9DHrxeLsMNNVXYiT0W5T/GQN76CFoauo3LvMit5SOTgjOam5kFe9E 6kZXSxadSlzxHKlglFkGoRSkNoH2KgayC5se6ut3aQ83w85UAlfLZYmaNO2vBdVowshZ 8uvH/y8MRfnG9aX7uppK+1rK0PS+xzHgkO78hULJTXb7fwK1Oh9n0QNcCIy8kBrUEpcC ZvsZlrd/8JnHRB///xONYcKIq4HmS9JnOhY0Mh30W+ujq/wKYyDBsarSgdV2SA6ms5IK SUSLyCWC9rxcaVbyh0ZhO1JFiE4yu0O3wWvd0Npk+Dto5aB3ERn3xEvH1KK2nKFiJ54U eF6g== X-Gm-Message-State: APjAAAWZrMD/zIpxdUQi+eKaJhv6hBkx+orBK7+26UCbsb1bJx7ViO7h w6zuN1RfyYmBLlisX7Y01aqwig== X-Google-Smtp-Source: APXvYqzRa5N5LhGfMTJuJ4oaj2D7z4BUkhWF/2X+DJwj0jTVnO/miJEr2SF9TZOAj1Aw+J5vr4kYmg== X-Received: by 2002:a17:906:434f:: with SMTP id z15mr9615390ejm.214.1568283556600; Thu, 12 Sep 2019 03:19:16 -0700 (PDT) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id q33sm4710068eda.60.2019.09.12.03.19.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 12 Sep 2019 03:19:15 -0700 (PDT) Received: by box.localdomain (Postfix, from userid 1000) id 1BD73100B4A; Thu, 12 Sep 2019 13:19:17 +0300 (+03) Date: Thu, 12 Sep 2019 13:19:17 +0300 From: "Kirill A. Shutemov" To: Steve Wahl Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , x86@kernel.org, Juergen Gross , Brijesh Singh , Jordan Borgner , Feng Tang , linux-kernel@vger.kernel.org, Baoquan He , russ.anderson@hpe.com, dimitri.sivanich@hpe.com, mike.travis@hpe.com Subject: Re: [PATCH] x86/boot/64: Make level2_kernel_pgt pages invalid outside kernel area. Message-ID: <20190912101917.mbobjvkxhfttxddd@box> References: <20190906212950.GA7792@swahl-linux> <20190909081414.5e3q47fzzruesscx@box> <20190910142810.GA7834@swahl-linux> <20190911002856.mx44pmswcjfpfjsb@box.shutemov.name> <20190911200835.GD7834@swahl-linux> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190911200835.GD7834@swahl-linux> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 11, 2019 at 03:08:35PM -0500, Steve Wahl wrote: > Thank you for your time looking into this with me! With all this explanation the original patch looks sane to me. But I would like to see more information from this thread in the commit message and some comments in the code on why it's crucial not to map more than needed. I think we also need to make it clear that this is workaround for a broken hardware: speculative execution must not trigger a halt. -- Kirill A. Shutemov