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 151E5C2BB1D for ; Tue, 7 Apr 2020 12:21:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1BF82063A for ; Tue, 7 Apr 2020 12:21:26 +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="nUq0d8G/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728648AbgDGMVZ (ORCPT ); Tue, 7 Apr 2020 08:21:25 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:41722 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728146AbgDGMVY (ORCPT ); Tue, 7 Apr 2020 08:21:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=pk/wTIvk5X/DA8IhsCZhc7nIIHKp7L4drvl4ax6UlCI=; b=nUq0d8G/UTbLmHOUMtDRZHG7G8 lmfBuv9l9XDCrfNeMMPzDX5LeWc4XlPOWSw1F8VqaQEA1X0o144IoW7upqJ/eCaqPpbMEDGNii59x mFJeYjXuyLzmBhZWTwSMuGThBX3edd89GQ21+Jb7PRs1RrG2CiMidbHYHH+oA9mi/uNegd4hQO4ck KU55v8J5n87l5CDbwymwwze/U3jxcOEcyCroM5B7korTt5WbAYaacEOI6+l7slJXtxni7yQCT2dBg L689SisLfiL8duhwNUHapm1s2FwQQVU4x68zHLGo/JeCNO3OEaAPUpIBmkXxpigDVhqlLzVizZNwN WCbZJkng==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jLnE2-0003qM-R2; Tue, 07 Apr 2020 12:21:06 +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 56F893010C8; Tue, 7 Apr 2020 14:21:03 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 3E48B2B907A89; Tue, 7 Apr 2020 14:21:03 +0200 (CEST) Date: Tue, 7 Apr 2020 14:21:03 +0200 From: Peter Zijlstra To: Keno Fischer Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , x86@kernel.org, "H. Peter Anvin" , Borislav Petkov , Dave Hansen , Andi Kleen , Kyle Huey , Robert O'Callahan Subject: Re: [RFC PATCH v2] x86/arch_prctl: Add ARCH_SET_XCR0 to set XCR0 per-thread Message-ID: <20200407122103.GU20730@hirez.programming.kicks-ass.net> References: <20200407011259.GA72735@juliacomputing.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200407011259.GA72735@juliacomputing.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 06, 2020 at 09:12:59PM -0400, Keno Fischer wrote: > This is a follow-up to my from two-years ago [1]. I've been using > rebased versions of that patch locally for my needs, but I've had > more people ask me about this patch recently, so I figured, I'd > have another go at this. Even if this doesn't make it into mainline, > I figure I can at least improve the quality of the patch for others > who want to use it. That's said, here's how this version is > different from v1: Aside of having an inconsistent comment style and whitespace damage, it adds exports without a module user. But my main reason for replying is asking: 'What the heck for?' You had a fairly long changelog detailing what the patchd does; but I've failed to find a single word on _WHY_ we want to do any of that.