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 4FA55C433F4 for ; Tue, 18 Sep 2018 17:29:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F399F21508 for ; Tue, 18 Sep 2018 17:29:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F399F21508 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 S1730344AbeIRXCk (ORCPT ); Tue, 18 Sep 2018 19:02:40 -0400 Received: from shelob.surriel.com ([96.67.55.147]:44724 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730089AbeIRXCk (ORCPT ); Tue, 18 Sep 2018 19:02:40 -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 1g2Jo5-0003mi-Gd; Tue, 18 Sep 2018 13:29:01 -0400 Message-ID: <11aa7d0f4ba36eff8b61a5dc1bd35ee5195fd576.camel@surriel.com> Subject: Re: [RFC PATCH 04/10 v2 ] x86/fpu: eager switch PKRU state From: Rik van Riel To: Sebastian Andrzej Siewior , Paolo Bonzini 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 13:29:01 -0400 In-Reply-To: <20180918160419.2zeru6xnufxixcax@linutronix.de> 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> <83e271e1298d603c1105dd0dbea32d67da9cf1fa.camel@surriel.com> <36e8493f-f994-e885-8fe6-2f0d4a9904a1@redhat.com> <20180918160419.2zeru6xnufxixcax@linutronix.de> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-qeo8C7RCdou6hmINJRZf" 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 --=-qeo8C7RCdou6hmINJRZf Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2018-09-18 at 18:04 +0200, Sebastian Andrzej Siewior wrote: > On 2018-09-18 17:29:52 [+0200], Paolo Bonzini wrote: > > > 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 > > What about copy_from/to_user? >=20 > This doesn't work for a kernel thread, does it? I mean they share the > init's MM and never do copy_{from|to}_user. Indeed, copy_from/to_user only works if current->mm points at an mm_struct with userspace memory. --=20 All Rights Reversed. --=-qeo8C7RCdou6hmINJRZf Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEKR73pCCtJ5Xj3yADznnekoTE3oMFAluhNd0ACgkQznnekoTE 3oN7+Af9GJYyy55zxm7fhdOa+X8DIovy7Le9zNpPgqRaoQLhctM69+uvP1wF7oQY V3wf3MrXD9eXq+DJHKqKFpfGcTAlIgl8YclJaEVE1vQjoKeYvfRmaXvMd+7Wguhv +3PeKQ9H5KD8w266Z/tUXJOh/Nxbtkd3Qvvx86bv6uiSkd4rqhYihi7x9n6biU2R UgxsbfPh/rmPN0RpNtAbPaWdq6XQ3SU/Z364+bMNFpW7kBVhMMw53D/ldpwusfo9 q9uvmSrA+DUtZloPpGaEMopMfpnnyby3EZ5Q+scfwC6YO0x9BoxKk0fOS2ImE++z 6tiOxmI1os93JUV7NLCOOL7Bpd7WGQ== =HdUP -----END PGP SIGNATURE----- --=-qeo8C7RCdou6hmINJRZf--