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=-4.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 7B831C43441 for ; Wed, 21 Nov 2018 18:15:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3FE2D214DB for ; Wed, 21 Nov 2018 18:15:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="pfr89o9N" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3FE2D214DB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733028AbeKVEuk (ORCPT ); Wed, 21 Nov 2018 23:50:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:46846 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730663AbeKVEuk (ORCPT ); Wed, 21 Nov 2018 23:50:40 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8BBDE214DA; Wed, 21 Nov 2018 18:15:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542824115; bh=DfnNtPdtQQywU0ua9lLs3e0JjU44XM9Q5lo0/njic98=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pfr89o9NEx75n13P/V74du9R0jGQ6kPQediLFoSfL0I7GLze2vtCZnCL4x1EjwcXQ Lc/gRREYjtihncKJKQNiVM0k0DdumYpQLuZRRJORBvjVsS2qmZ3t8+HCcRxpKMSgiu A6vcwKhoB36Ac1sVbzFNwNVWIhW/qFevj0Y403wA= Date: Wed, 21 Nov 2018 19:15:13 +0100 From: Greg Kroah-Hartman To: Tim Chen Cc: Jiri Kosina , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Thomas Gleixner , Peter Zijlstra , Josh Poimboeuf , Andrea Arcangeli , WoodhouseDavid , Andi Kleen , SchauflerCasey , Dave Stewart Subject: Re: [PATCH 4.19 041/361] x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation Message-ID: <20181121181513.GA30870@kroah.com> References: <20181111221619.915519183@linuxfoundation.org> <20181111221625.598298393@linuxfoundation.org> <20181121135611.GA26411@kroah.com> <41234d20-294f-d0f4-336c-64bf9fcb92a7@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <41234d20-294f-d0f4-336c-64bf9fcb92a7@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 21, 2018 at 09:47:48AM -0800, Tim Chen wrote: > On 11/21/2018 05:56 AM, Greg Kroah-Hartman wrote: > > On Wed, Nov 21, 2018 at 02:21:15PM +0100, Jiri Kosina wrote: > >> On Sun, 11 Nov 2018, Greg Kroah-Hartman wrote: > >> > >>> 4.19-stable review patch. If anyone has any objections, please let me know. > >> > >> Greg, please drop this patch from all -stable for now. Version that > >> wouldn't have such performance impact is being worked on. > > > > Is it reverted in Linus's tree? If not, then anything that comes "later > > on" will not apply here, right? > > > > I see the thread asking about this, but I got really conflicting > > messages here, and now it's in all of the latest releases, and no > > testing seems to have uncovered issues. Is it just a "slow down" > > problem? > > Greg, > > It could be a big slow down in excess of 20% for some applications. > And cross sibling Spectre v2 attack is quite hard to pull off. > > So till we have the accompanying patchset that only apply STIBP on processes > that really need it instead of universally, it should be withheld from > stable. Ok, now reverted, thanks. greg k-h