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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 32CA8C43387 for ; Mon, 14 Jan 2019 14:39:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 044082086D for ; Mon, 14 Jan 2019 14:39:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726579AbfANOjf (ORCPT ); Mon, 14 Jan 2019 09:39:35 -0500 Received: from mga18.intel.com ([134.134.136.126]:45789 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726554AbfANOjf (ORCPT ); Mon, 14 Jan 2019 09:39:35 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Jan 2019 06:39:34 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,477,1539673200"; d="scan'208";a="118113579" Received: from avandeve-mobl.amr.corp.intel.com (HELO [10.251.20.134]) ([10.251.20.134]) by orsmga003.jf.intel.com with ESMTP; 14 Jan 2019 06:39:34 -0800 Subject: Re: [PATCH] x86/speculation: Add document to describe Spectre and its mitigations To: Jiri Kosina , Pavel Machek Cc: Tim Chen , Jonathan Corbet , Thomas Gleixner , Linus Torvalds , Tom Lendacky , Ingo Molnar , Peter Zijlstra , Josh Poimboeuf , Andrea Arcangeli , David Woodhouse , Andi Kleen , Dave Hansen , Asit Mallick , Jon Masters , Waiman Long , Greg KH , Borislav Petkov , linux-kernel@vger.kernel.org, x86@kernel.org, stable@vger.kernel.org References: <64efec3fda40c0758601bf9b1480a35d76d3c487.1545413988.git.tim.c.chen@linux.intel.com> <20181228103437.4c03c181@lwn.net> <20190113231001.GB18710@amd> <20190114120157.GB21544@amd> <20190114130153.GC21544@amd> From: Arjan van de Ven Message-ID: <5907b2bc-8498-2f28-eb90-13627d492496@linux.intel.com> Date: Mon, 14 Jan 2019 06:39:33 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On 1/14/2019 5:06 AM, Jiri Kosina wrote: > On Mon, 14 Jan 2019, Pavel Machek wrote: > >> Frankly I'd not call it Meltdown, as it works only on data in the cache, >> so the defense is completely different. Seems more like a l1tf >> :-). > > Meltdown on x86 also seems to work only for data in L1D, but the pipeline > could be constructed in a way that data are actually fetched into L1D > before speculation gives up, which is not the case on ppc (speculation > aborts on L2->L1 propagation IIRC). That's why flushing L1D on ppc is > sufficient, but on x86 it's not. assuming L1D is not shared between SMT threads obviously :) >