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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,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 A2B1AC433E0 for ; Mon, 8 Mar 2021 16:52:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 289266518D for ; Mon, 8 Mar 2021 16:52:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 289266518D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9BB438D0050; Mon, 8 Mar 2021 11:52:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 96AF78D001D; Mon, 8 Mar 2021 11:52:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7BE0A8D0050; Mon, 8 Mar 2021 11:52:26 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0037.hostedemail.com [216.40.44.37]) by kanga.kvack.org (Postfix) with ESMTP id 5F2A68D001D for ; Mon, 8 Mar 2021 11:52:26 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 0405C3AA7 for ; Mon, 8 Mar 2021 16:52:26 +0000 (UTC) X-FDA: 77897300292.27.B2095C5 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by imf18.hostedemail.com (Postfix) with ESMTP id 4B6EB20053FF for ; Mon, 8 Mar 2021 16:52:06 +0000 (UTC) IronPort-SDR: H+B5rVggWzOtBuk8T4v18YxDitEklRiwvoBOUA0aJpoGFlp5ANHso7IXwXHuWqtUDYIguY5RK8 mypPSHE7dc4Q== X-IronPort-AV: E=McAfee;i="6000,8403,9917"; a="252092139" X-IronPort-AV: E=Sophos;i="5.81,232,1610438400"; d="scan'208";a="252092139" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Mar 2021 08:51:58 -0800 IronPort-SDR: Ra6tLTStpq8dq36RZhKli0M2oVxfITFaaO3HQz+7ILvFtrtpvijqoqpCk6bbPegkcGxyt+LxRG 15Q2Lh7fpluQ== X-IronPort-AV: E=Sophos;i="5.81,232,1610438400"; d="scan'208";a="385909914" Received: from yyu32-mobl1.amr.corp.intel.com (HELO [10.209.186.31]) ([10.209.186.31]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Mar 2021 08:51:56 -0800 Subject: Re: [PATCH v21 10/26] x86/mm: Update pte_modify for _PAGE_COW To: Borislav Petkov Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Haitao Huang References: <20210217222730.15819-1-yu-cheng.yu@intel.com> <20210217222730.15819-11-yu-cheng.yu@intel.com> <20210305142940.GC2685@zn.tnic> From: "Yu, Yu-cheng" Message-ID: Date: Mon, 8 Mar 2021 08:51:55 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210305142940.GC2685@zn.tnic> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Stat-Signature: 4bsrfdxqkfk354adtgfpky35e64pupqn X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 4B6EB20053FF Received-SPF: none (intel.com>: No applicable sender policy available) receiver=imf18; identity=mailfrom; envelope-from=""; helo=mga07.intel.com; client-ip=134.134.136.100 X-HE-DKIM-Result: none/none X-HE-Tag: 1615222326-335621 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 3/5/2021 6:29 AM, Borislav Petkov wrote: > On Wed, Feb 17, 2021 at 02:27:14PM -0800, Yu-cheng Yu wrote: >> @@ -787,16 +802,34 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) >> */ >> val &= _PAGE_CHG_MASK; >> val |= check_pgprot(newprot) & ~_PAGE_CHG_MASK; >> + val = fixup_dirty_pte(val); > > Do I see it correctly that you can do here and below: > > /* > * Fix up potential shadow stack page flags because the RO, Dirty PTE is > * special. > */ > if (pte_dirty()) { > pte_mkclean(); > pte_mkdirty(); > } > > ? Yes, this looks better. Thanks! > > That fixup thing looks grafted and not like a normal flow to me. >