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=1.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, FSL_HELO_FAKE,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 9D3F7C43441 for ; Mon, 26 Nov 2018 13:37:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 62C0620862 for ; Mon, 26 Nov 2018 13:37:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Qposv00d" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 62C0620862 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.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 S1726763AbeK0Aby (ORCPT ); Mon, 26 Nov 2018 19:31:54 -0500 Received: from mail-wm1-f44.google.com ([209.85.128.44]:56065 "EHLO mail-wm1-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726231AbeK0Abx (ORCPT ); Mon, 26 Nov 2018 19:31:53 -0500 Received: by mail-wm1-f44.google.com with SMTP id y139so18201672wmc.5 for ; Mon, 26 Nov 2018 05:37:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=JHnG0Qt8Q8UOZMoGZkQPlCPmbW+eVM6efrgpPG76T1Y=; b=Qposv00dtVpZDSqZs1N0QUgzTx2k2H6glYeO67l3ui3hZmAWElYuNOPd1rkvbr/geF f6vbBLBieaYGsN4I/JVKY9faTPKIAQfkTgS9sKDpBVwXk2qZ1sXyhcnisfmeeebk7olp OMr86vo+ACMwO/fifHdFw27Nloy/6B9IuxokAKwco7Q7nMMfDoQQqJES9dPwASaIrwQx /nJ6M1oPClptffVRGckMrNYXiCouN9txKjWkZayy1p8e572BcpjJu2/2WjqNwO1dfFuc QafZy+qR38KW1Anfk9+dn8wNsi9JFIGkW7LAdjWx+p1hu6/VpeCfAxwFctgaFBcXJaXM lOXQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=JHnG0Qt8Q8UOZMoGZkQPlCPmbW+eVM6efrgpPG76T1Y=; b=i0bMs/fj8eVafvbI3D8cOnp5Rz6BKVTaTZ9mS4l1AJpiY1OUr+ZH/Cbg2uIogDGerh Rg3gM6yMNa5g0GqpWtNS3ZrwawUriWb7HO11kPMmtw9bjJ3ZUGPmG7IAFsS0YC+jjvqN rEUKBOGCFzTjxjRwoLRyc6fVlog+IzfpkuZ254oce33bb/cCa15AVDs409wh9rWhNVqW KFufUQ5Pukv5a/oz6pVBZBmaw9hb1p/lhTFTanJ8jWRfhMSzs1L5jdbHrCPfY4S7xJ2f gDFQ0KcMQlq3m0KAwdy5PkiUlr5iVTgZkVU1ex915inrRbL0qvUewFSrCXjpBVsBxy/r 19cA== X-Gm-Message-State: AA+aEWYLYTDimrJZUI0RCvdcR+spXQ1nd5MQi1nI2vczruQ0EG6pdzN8 UpHj+OfJBi3ksab7kp36FFQ= X-Google-Smtp-Source: AJdET5cIZqXp934eO0XKvbD1zUznpO53e4IjB3EUiHwV0Ph4N35er7UgT/SS7i8AXkmg57nOGl7DKg== X-Received: by 2002:a1c:aecb:: with SMTP id x194mr21951039wme.96.1543239462438; Mon, 26 Nov 2018 05:37:42 -0800 (PST) Received: from gmail.com (2E8B0CD5.catv.pool.telekom.hu. [46.139.12.213]) by smtp.gmail.com with ESMTPSA id a1sm339618wrw.76.2018.11.26.05.37.40 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 26 Nov 2018 05:37:41 -0800 (PST) Date: Mon, 26 Nov 2018 14:37:39 +0100 From: Ingo Molnar To: Thomas Gleixner Cc: LKML , x86@kernel.org, Peter Zijlstra , Andy Lutomirski , Linus Torvalds , Jiri Kosina , Tom Lendacky , Josh Poimboeuf , Andrea Arcangeli , David Woodhouse , Tim Chen , Andi Kleen , Dave Hansen , Casey Schaufler , Asit Mallick , Arjan van de Ven , Jon Masters , Waiman Long , Greg KH , Dave Stewart , Kees Cook Subject: Re: [patch V2 00/28] x86/speculation: Remedy the STIBP/IBPB overhead Message-ID: <20181126133739.GC108014@gmail.com> References: <20181125183328.318175777@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181125183328.318175777@linutronix.de> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Thomas Gleixner wrote: > Thats hopefully the final version of this. Changes since V1: > > - Renamed the command line option and related code to spectre_v2_user= as > suggested by Josh. > > - Thought more about the back to back optimization and finally left the > IBPB code in switch_mm(). > > It still removes the ptrace check for the always IBPB case. That's > substantial overhead for dubious value now that the default is > conditional (prctl/seccomp) IBPB. > > - Added two options which allow conditional STIBP and IBPB always mode. > > - Addressed the review comments With the typo review feedback outlined in the discussions: Reviewed-by: Ingo Molnar Thanks, Ingo