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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 8C470C433DF for ; Wed, 27 May 2020 10:34:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6677C207CB for ; Wed, 27 May 2020 10:34:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="mP8NX0pu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729881AbgE0KeJ (ORCPT ); Wed, 27 May 2020 06:34:09 -0400 Received: from merlin.infradead.org ([205.233.59.134]:53414 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728983AbgE0KeG (ORCPT ); Wed, 27 May 2020 06:34:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=+ZMb7ayskfYmUMDD9vA/QW3XXA6gbYOmgUP9dQQUd5U=; b=mP8NX0puwAj0/ZU6+jWX/0WQ3e 8ygp9uA3lrNb4s3vGm00FjArWHocZnsNIRCZ4XB4DwqarHYo/Cs2MWU6GDuB3mmwmYzD43iHHL9cA x2SB+T0aw3iNHL5ZflXtVA7xWGHZi+yFYohUH89W51GojX3uyfRT8AJHdCKkFDxiNrSZXiXLGfOEf GKZ2Lc+1zS6NBRgmh8XsYqT3QlJVdX17eBX9UAepbGAV06PgsW87eHEZvnKH3q91j2Zp3Vsz1XxeH arsw0vw7sEkXS+RVmXZo8KiZz08FACCrhtvcF+F4JlIuvhx3vSWPMEUgT7Ji2XXWvWRYWzrLd3HmG AgV/5NfA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jdtLh-000180-96; Wed, 27 May 2020 10:31:49 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 88892300478; Wed, 27 May 2020 12:31:47 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 689CB2BD9C2B9; Wed, 27 May 2020 12:31:47 +0200 (CEST) Date: Wed, 27 May 2020 12:31:47 +0200 From: Peter Zijlstra To: Andi Kleen Cc: Kees Cook , Greg KH , x86@kernel.org, linux-kernel@vger.kernel.org, sashal@kernel.org, Andi Kleen , stable@vger.kernel.org Subject: Re: [PATCH v1] x86: Pin cr4 FSGSBASE Message-ID: <20200527103147.GI325280@hirez.programming.kicks-ass.net> References: <20200526052848.605423-1-andi@firstfloor.org> <202005260935.EB11D3EB7@keescook> <20200526231423.qcsolcpll534sgro@two.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200526231423.qcsolcpll534sgro@two.firstfloor.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 26, 2020 at 04:14:25PM -0700, Andi Kleen wrote: > > And if this is going to be more permanent, we can separate the mask > > (untested): > > The FSGSBASE one should not be permanent, it will be replaced > with the full FSGSBASE patches that set that bit correctly. Well, even with full FSGSBASE patches on, that CR4 bit should never get changed after boot.