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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 5E476C282C2 for ; Wed, 13 Feb 2019 09:35:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 21FA121901 for ; Wed, 13 Feb 2019 09:35:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="X50LubJu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732036AbfBMJf4 (ORCPT ); Wed, 13 Feb 2019 04:35:56 -0500 Received: from mail.skyhub.de ([5.9.137.197]:39374 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729130AbfBMJf4 (ORCPT ); Wed, 13 Feb 2019 04:35:56 -0500 Received: from zn.tnic (p200300EC2BCDE800B80E9BCAB03A01F8.dip0.t-ipconnect.de [IPv6:2003:ec:2bcd:e800:b80e:9bca:b03a:1f8]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 345C41EC023E; Wed, 13 Feb 2019 10:35:54 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1550050554; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=N5/toTELGAqlZtYf4FeiaGSNLAzH4vpz7vTIi12M5Ao=; b=X50LubJu5vnYaSAmILCiUO4ilOhTxJ2fLBRG202VLw2v7g0v5yBRV6TXAYypxpgae6b+F6 HU/p+a2TxPOcV6qQU8K1qRwZqanSy34+63lW2qJCuauUvnISsL5LGosEXg5s1nwrNIQE/K MdN/RJnIixwTi97mA+2ibHBklVdOrcM= Date: Wed, 13 Feb 2019 10:35:53 +0100 From: Borislav Petkov To: Sebastian Andrzej Siewior Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Andy Lutomirski , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen Subject: Re: [PATCH 15/22] x86/entry: Add TIF_NEED_FPU_LOAD Message-ID: <20190213093553.GC9683@zn.tnic> References: <20190109114744.10936-1-bigeasy@linutronix.de> <20190109114744.10936-16-bigeasy@linutronix.de> <20190130115507.GE18383@zn.tnic> <20190207114941.jzydrry5xpjngyiv@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190207114941.jzydrry5xpjngyiv@linutronix.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 07, 2019 at 12:49:42PM +0100, Sebastian Andrzej Siewior wrote: > On 2019-01-30 12:55:07 [+0100], Borislav Petkov wrote: > > This definitely needs to be written somewhere in > > > > arch/x86/include/asm/fpu/internal.h > > > > or where we decide to put the FPU handling rules. > > Added: > > Index: staging/arch/x86/include/asm/fpu/internal.h > =================================================================== > --- staging.orig/arch/x86/include/asm/fpu/internal.h > +++ staging/arch/x86/include/asm/fpu/internal.h > @@ -537,6 +537,12 @@ static inline void __fpregs_load_activat > * > * The FPU context is only stored/restore for user task and ->mm is used to > * distinguish between kernel and user threads. > + * > + * If TIF_NEED_FPU_LOAD is cleared then CPU's FPU registers are holding the > + * current content of current()'s FPU register state. "current content of current" - that's a lot of c... Make that "... then the CPU's FPU registers are mirrored in the current thread's FPU registers state." > + * If TIF_NEED_FPU_LOAD is set then CPU's FPU registers may not hold current()'s > + * FPU registers. It is required to load the register before returning to ^^^^^^^^ s/register/registers/ - plural. Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.