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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 BD281ECE564 for ; Tue, 18 Sep 2018 16:04:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6EAE1214DD for ; Tue, 18 Sep 2018 16:04:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6EAE1214DD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linutronix.de 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 S1730103AbeIRVhh (ORCPT ); Tue, 18 Sep 2018 17:37:37 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:58197 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729447AbeIRVhh (ORCPT ); Tue, 18 Sep 2018 17:37:37 -0400 Received: from bigeasy by Galois.linutronix.de with local (Exim 4.80) (envelope-from ) id 1g2IU8-0005FO-6L; Tue, 18 Sep 2018 18:04:20 +0200 Date: Tue, 18 Sep 2018 18:04:20 +0200 From: Sebastian Andrzej Siewior To: Paolo Bonzini Cc: Rik van Riel , linux-kernel@vger.kernel.org, x86@kernel.org, Andy Lutomirski , Radim =?utf-8?B?S3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" Subject: Re: [RFC PATCH 04/10 v2 ] x86/fpu: eager switch PKRU state Message-ID: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <36e8493f-f994-e885-8fe6-2f0d4a9904a1@redhat.com> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > > What about copy_from/to_user? 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. > Paolo Sebastian