From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail02.groups.io (mail02.groups.io [66.175.222.108]) by spool.mail.gandi.net (Postfix) with ESMTPS id 8C42BAC0E8E for ; Fri, 26 Jan 2024 13:19:14 +0000 (UTC) DKIM-Signature: a=rsa-sha256; bh=cWdNDZSJw2wRV7DJnsIWOyreNwZC3bExOIYRP4pcI1k=; c=relaxed/simple; d=groups.io; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version:In-Reply-To:Precedence:List-Subscribe:List-Help:Sender:List-Id:Mailing-List:Delivered-To:Reply-To:List-Unsubscribe-Post:List-Unsubscribe:Content-Type:Content-Disposition; s=20140610; t=1706275153; v=1; b=TeG8d9u/EkvpeJzxOGYkJBrQCcEq0WtuSsBSd3y6uFsIJpGS0QW8g7sQw2nSgk3JLWdZr7LL Ac4IBpswQct/n19jzG3Au1lMrk4SxhSCUdkrr+jv4svOllHXFxPe5efYn9Av65YP4oDbfhtMbFY OOFmD9PV1uG0+u2DpRq8NPSs= X-Received: by 127.0.0.2 with SMTP id KMjRYY7687511xQMQU9DyvxN; Fri, 26 Jan 2024 05:19:13 -0800 X-Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by mx.groups.io with SMTP id smtpd.web10.15618.1706275152376475040 for ; Fri, 26 Jan 2024 05:19:12 -0800 X-Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-502-4ylBk25EO2O5MiunJ-vZ9A-1; Fri, 26 Jan 2024 08:19:08 -0500 X-MC-Unique: 4ylBk25EO2O5MiunJ-vZ9A-1 X-Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9552C2812FFD; Fri, 26 Jan 2024 13:19:07 +0000 (UTC) X-Received: from sirius.home.kraxel.org (unknown [10.39.194.174]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6FBD31C060AF; Fri, 26 Jan 2024 13:19:06 +0000 (UTC) X-Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 0A00D1800605; Fri, 26 Jan 2024 14:19:06 +0100 (CET) Date: Fri, 26 Jan 2024 14:19:05 +0100 From: "Gerd Hoffmann" To: "Liu, Zhiguang" Cc: "devel@edk2.groups.io" , "Ni, Ray" , Liming Gao , =?utf-8?B?TMOhc3psw7Mgw4lyc2Vr?= , Oliver Steffen Subject: Re: [edk2-devel] [PATCH v2 1/2] MdeModulePkg: rename PcdUse5LevelPageTable to PcdEnable5LevelPageTable Message-ID: References: <20240125082057.309133-1-kraxel@redhat.com> <20240125082057.309133-2-kraxel@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Precedence: Bulk List-Subscribe: List-Help: Sender: devel@edk2.groups.io List-Id: Mailing-List: list devel@edk2.groups.io; contact devel+owner@edk2.groups.io Reply-To: devel@edk2.groups.io,kraxel@redhat.com List-Unsubscribe-Post: List-Unsubscribe=One-Click List-Unsubscribe: X-Gm-Message-State: XEQpC9ugvvmlQSBBElXrGHTax7686176AA= Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-GND-Status: LEGIT Authentication-Results: spool.mail.gandi.net; dkim=pass header.d=groups.io header.s=20140610 header.b="TeG8d9u/"; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=redhat.com (policy=none); spf=pass (spool.mail.gandi.net: domain of bounce@groups.io designates 66.175.222.108 as permitted sender) smtp.mailfrom=bounce@groups.io On Fri, Jan 26, 2024 at 02:49:13AM +0000, Liu, Zhiguang wrote: > Hi Gerd, > For the PCD, it current has below usage. > 1) for 32-bit PEI and 64-bit DXE, this PCD will decide if use 5 level paging in DXE. Yes. That is the only real use of the PCD today. I expect the days of 32bit BEI / 64bit DXE firmware builds are numbered though. There has been a steady stream of patches from intel to push edk2 to full 64-bit support, and there also is the x86s proposal[1]. > 2) for 64-bit PEI and DXE, reset vector chooses if use 5 level paging > in early phase. But BIOS can still switch paging mode based on this > PCD later. I don't think edk2 implements the paging mode switch. It's also not that easy to do because the paging mode can only be switched with paging turned off (which implies long mode turned off too). > Since this PCD can be dynamic, we can let user to choose different > paging mode in BIOS setup menu, and use this paging mode on reboot. Is there any (pure 64-bit) firmware actually implementing this today? > You may want to use one BIOS to support machine with different la57 capability, I assume two possible ways: > 1) make the PCD as dynamic, and set it based on la57 capability. You mean la57 state I assume (i.e. cr4.la57)? i.e. for the 32-PEI / 64-DXE builds the PCD decides which mode will be used, and for pure 64-bit builds the PCD will be set according to the mode the CPU is running in? take care, Gerd -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#114609): https://edk2.groups.io/g/devel/message/114609 Mute This Topic: https://groups.io/mt/103950404/7686176 Group Owner: devel+owner@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [rebecca@openfw.io] -=-=-=-=-=-=-=-=-=-=-=-