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=-17.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 F29BAC47082 for ; Mon, 24 May 2021 03:09:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D123B61151 for ; Mon, 24 May 2021 03:09:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232231AbhEXDKn (ORCPT ); Sun, 23 May 2021 23:10:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:58210 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232200AbhEXDKl (ORCPT ); Sun, 23 May 2021 23:10:41 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A411261151; Mon, 24 May 2021 03:09:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621825754; bh=ctT3Pp3VdMz2xN/P8yl3Ml87iHNwfU+tatN/MfiCkZQ=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=C8DdV/93M7Aj+fiKzZ8Eq2kaPm2guPytAEtVzdxNwUHVhvR1wHKmcgQHZ9mHWlTPr pbLKDTO3D2tlHWr/nBbIcLmFleUwgfSRKmdNkd07dkpWaI9MG94PVK9vZuY7WqW9VI 9KW4lpjg16O9kfQnTEgN+7Uj9yics4Up3CQHm64rkFkzG/LVrDrgbUKjArt/2uw1Wl P7Y2lzz6V77puhLiP4WYyc22CMMJzfXP7A2ujszWP/sCgzBPv/oeUyhqHikIi1PiJy 6X0eVOz4V+5mZKtOWlBXGnyHCYKSXpb17bRQVWKxO909bI7mYSDco+2M92ndNZXxji c6/hMMElXftJw== Subject: Re: [PATCH v5 21/28] x86/fpu/amx: Initialize child's AMX state To: "Chang S. Bae" , bp@suse.de, tglx@linutronix.de, mingo@kernel.org, x86@kernel.org Cc: len.brown@intel.com, dave.hansen@intel.com, jing2.liu@intel.com, ravi.v.shankar@intel.com, linux-kernel@vger.kernel.org References: <20210523193259.26200-1-chang.seok.bae@intel.com> <20210523193259.26200-22-chang.seok.bae@intel.com> From: Andy Lutomirski Message-ID: <8c8d91ae-5a3b-9523-725d-134840102df7@kernel.org> Date: Sun, 23 May 2021 20:09:13 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20210523193259.26200-22-chang.seok.bae@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/23/21 12:32 PM, Chang S. Bae wrote: > Assure that a forked child starts AMX registers in the INIT-state. > > Signed-off-by: Chang S. Bae > Reviewed-by: Len Brown > Cc: x86@kernel.org > Cc: linux-kernel@vger.kernel.org > --- > Changes from v4: > * Added as a new patch. This was missing on previous versions. > --- > arch/x86/kernel/fpu/core.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c > index 016c3adebec3..cccfeafe81e5 100644 > --- a/arch/x86/kernel/fpu/core.c > +++ b/arch/x86/kernel/fpu/core.c > @@ -285,6 +285,10 @@ int fpu__copy(struct task_struct *dst, struct task_struct *src) > > fpregs_unlock(); > > + /* AMX state is volatile, children do not inherit it. */ > + if (xfeatures_mask_all & XFEATURE_MASK_XTILE) > + dst_fpu->state->xsave.header.xfeatures &= ~(XFEATURE_MASK_XTILE); > + > set_tsk_thread_flag(dst, TIF_NEED_FPU_LOAD); > > trace_x86_fpu_copy_src(src_fpu); > If we're going to start having different states with different behaviors, let's make them real defines. #define XFEATURE_MASK_CLEARED_ON_CLONE ... --Andy