From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=209.132.183.28; helo=mx1.redhat.com; envelope-from=lersek@redhat.com; receiver=edk2-devel@lists.01.org Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 8CCDA21A07A92 for ; Tue, 9 Oct 2018 01:54:14 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 237C485363; Tue, 9 Oct 2018 08:54:14 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-120-35.rdu2.redhat.com [10.10.120.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id 49FD45C48E; Tue, 9 Oct 2018 08:54:13 +0000 (UTC) To: "Ni, Ruiyu" , "Dong, Eric" , "edk2-devel@lists.01.org" References: <20181009015118.13856-1-eric.dong@intel.com> <06befab9-cbd6-59ab-c85e-deab4002824c@Intel.com> <062a4679-e3bf-28f1-31ba-83a124abb655@Intel.com> From: Laszlo Ersek Message-ID: Date: Tue, 9 Oct 2018 10:54:12 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <062a4679-e3bf-28f1-31ba-83a124abb655@Intel.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 09 Oct 2018 08:54:14 +0000 (UTC) Subject: Re: [Patch] UefiCpuPkg/S3Resume2Pei: disable paging before creating new page table. X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Oct 2018 08:54:14 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 10/09/18 10:26, Ni, Ruiyu wrote: > On 10/9/2018 4:09 PM, Laszlo Ersek wrote: >>> >>> Two comments: >>> 1. We'd better not map the PcdCpuStackGuard to paging-enable. Maybe some >>> other feature also enables the paging in PEI phase but the >>> PcdCpuStackGuard is FALSE. >> >> I think I agree. >> >>> 2. When PEI is in 64bit mode, disabling paging may not work because >>> paging-enable is a must in 64bit mode. >> >> I think this case is academic. S3Resume2Pei does not support 64-bit PEI >> with SMM enabled. This is why we have commit 5133d1f1d297 ("OvmfPkg: >> replace README fine print about X64 SMM S3 with PlatformPei check", >> 2015-11-30) in OVMF. > > I found that commit. I just checked S3Resume2Pei module. It does assumes > it's running in 32bit mode. And CpuS3.c also assumes S3Resume2Pei is > running in 32bit mode. > >> >> Anyway, I'm making this comment in the general sense only. I'm not >> suggesting that we disable paging unconditionally. Actually, I believe, >> I will suggest (under the v3 posting) restricting the write to CR0 even >> more. > Why? I explained under v3. Thanks, Laszlo