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=-3.8 required=3.0 tests=BAYES_00,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 CAE56C433E7 for ; Wed, 2 Sep 2020 12:54:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A22B020829 for ; Wed, 2 Sep 2020 12:54:53 +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="CJFTE95K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726285AbgIBMyq (ORCPT ); Wed, 2 Sep 2020 08:54:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727028AbgIBMyM (ORCPT ); Wed, 2 Sep 2020 08:54:12 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26BD2C061245; Wed, 2 Sep 2020 05:54:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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=isrzndUDYiz7AVFuWayAZA6ecBCJ63M610eK0GJhjus=; b=CJFTE95KS0gBy1UFDjdzh0P6Zl vDTCAlAnnxWW+J6nr0RwUn6VRG66ylaYFPPlvlH8rhBCX30JAYid8uFSWuD69AtxC76S30Nr9yXsl H9eSsb8jb691xbcuFWqBvs8VP94SA83/8/9kYBol3nd+u6Kw5IwsV0Hk7tHlS+sSfBM/nIW8oe1Ld NuJu5EM1RRyv7zitERugqVYenzVQi7IoEjJFh8U4MGebZbpucb8EHJA9shCLT3QeAcitanIwf1GXL hStgfJKmdVxowB0QR8dps2hyFpcFWoP2BEp4/AhKrNEmBmnuKbo2ZTE+mBMXLgyJG+bQq8WDwt5/L 6ggoxK7Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDSH5-00015w-UD; Wed, 02 Sep 2020 12:54:04 +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 F0D3E3011C6; Wed, 2 Sep 2020 14:54:02 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id DE4C423D3D75E; Wed, 2 Sep 2020 14:54:02 +0200 (CEST) Date: Wed, 2 Sep 2020 14:54:02 +0200 From: peterz@infradead.org To: Nadav Amit Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Nadav Amit , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Andy Lutomirski , Kees Cook , stable@vger.kernel.org Subject: Re: [PATCH] x86/special_insn: reverse __force_order logic Message-ID: <20200902125402.GG1362448@hirez.programming.kicks-ass.net> References: <20200901161857.566142-1-namit@vmware.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200901161857.566142-1-namit@vmware.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 01, 2020 at 09:18:57AM -0700, Nadav Amit wrote: > Unless I misunderstand the logic, __force_order should also be used by > rdpkru() and wrpkru() which do not have dependency on __force_order. I > also did not understand why native_write_cr0() has R/W dependency on > __force_order, and why native_write_cr4() no longer has any dependency > on __force_order. There was a fairly large thread about this thing here: https://lkml.kernel.org/r/20200527135329.1172644-1-arnd@arndb.de I didn't keep up, but I think the general concensus was that it's indeed a bit naf.