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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 3D76AECE564 for ; Tue, 18 Sep 2018 15:11:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E6A98214DD for ; Tue, 18 Sep 2018 15:11:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E6A98214DD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=surriel.com 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 S1729951AbeIRUoX (ORCPT ); Tue, 18 Sep 2018 16:44:23 -0400 Received: from shelob.surriel.com ([96.67.55.147]:41694 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727228AbeIRUoX (ORCPT ); Tue, 18 Sep 2018 16:44:23 -0400 Received: from imladris.surriel.com ([96.67.55.152]) by shelob.surriel.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1g2Heq-0001r4-Qp; Tue, 18 Sep 2018 11:11:20 -0400 Message-ID: <83e271e1298d603c1105dd0dbea32d67da9cf1fa.camel@surriel.com> Subject: Re: [RFC PATCH 04/10 v2 ] x86/fpu: eager switch PKRU state From: Rik van Riel To: Paolo Bonzini , Sebastian Andrzej Siewior Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Andy Lutomirski , Radim =?UTF-8?Q?Kr=C4=8Dm=C3=A1=C5=99?= , kvm@vger.kernel.org, "Jason A. Donenfeld" Date: Tue, 18 Sep 2018 11:11:20 -0400 In-Reply-To: <7e9a13f3-93f5-fe4a-20d2-f4f9407bd43b@redhat.com> References: <20180912133353.20595-1-bigeasy@linutronix.de> <20180912133353.20595-5-bigeasy@linutronix.de> <8e5b64e4-b3e6-f884-beb6-b7b69ab2d8c1@redhat.com> <20180914203501.qibhpmueosvkr74w@linutronix.de> <20180918142701.atfb4ul45k7tl6ew@linutronix.de> <7e9a13f3-93f5-fe4a-20d2-f4f9407bd43b@redhat.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-c268XyDDyxQNM28MvnHT" X-Mailer: Evolution 3.28.5 (3.28.5-1.fc28) Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-c268XyDDyxQNM28MvnHT Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2018-09-18 at 17:07 +0200, Paolo Bonzini wrote: > On 18/09/2018 16:27, Sebastian Andrzej Siewior wrote: > > > Likewise, move this to fpu__clear and outside "if > > > (static_cpu_has(X86_FEATURE_FPU))"? > >=20 > > okay. But if there is no FPU we did not save/restore the pkru > > value. Is > > this supposed to be an improvement? >=20 > Honestly it just seemed "more correct", but now that I think about > it, > kernel threads should run with PKRU=3D0. maybe there's a preexisting > bug > that your patch has the occasion to fix. I don't think it matters what the PKRU state is for kernel threads, since kernel PTEs should not be using protection keys anyway. --=20 All Rights Reversed. --=-c268XyDDyxQNM28MvnHT Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEKR73pCCtJ5Xj3yADznnekoTE3oMFAluhFZgACgkQznnekoTE 3oNJbwf6AoBSP1/VOt6BOOQyRo7whsUYPZoXm/nP5aAUt6ujM0sf49T/gQUgO7Rw O7I2zbvZUlKijD6Mf3be/2QNYjs8Y14hf84HvUmo2pSAPbq+wRTCVhvut6SHMnHd sOeAfJHLUZ6olAZZt5HwXZUdU72hG85anEfMuy3oJU6G1bG4h46QiBkyICAgYKtt ui4BopFK+mX+yPbohcjG448aitAXG5vNqNsdxYPGhx9ovcTpw3KDqJgUy5olrtPn /OtqfNyKwmc9FYIEwyebfwnaWhsQ+UdA6p45Me2Ajx9gPpvci9XCsn/NnZkq5/RL kM70oAa8N6bczzkf1byEvPMZWcUlMg== =s8Yo -----END PGP SIGNATURE----- --=-c268XyDDyxQNM28MvnHT--