From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by mx.groups.io with SMTP id smtpd.web08.5751.1645610853168522507 for ; Wed, 23 Feb 2022 02:07:33 -0800 Authentication-Results: mx.groups.io; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=d2x4Q1XJ; spf=pass (domain: redhat.com, ip: 170.10.129.124, mailfrom: kraxel@redhat.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645610851; 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: in-reply-to:in-reply-to:references:references; bh=X9SVBGBFQ7DEf8JeQa7eoU7WmzX1prNcXthORmM9yNo=; b=d2x4Q1XJt4zVhtBckD8sz2cN9w2ITEfH3HsIs4R4XTLZn3FOj6o7yNBkzw9WqVulLUKDH4 GemQrTFeCnao3uNatkWrVoOrbWZj+MXNxqXtTmdBSeoUBMLapoMGi5ciJeFHKAMux5Nlv6 4cm0H0kb7CgEEfUN1YBwZ2p4UINonpU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-385-FEosmlKxNAqbtnOy-6Fjaw-1; Wed, 23 Feb 2022 05:07:28 -0500 X-MC-Unique: FEosmlKxNAqbtnOy-6Fjaw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EE2065125; Wed, 23 Feb 2022 10:07:26 +0000 (UTC) Received: from sirius.home.kraxel.org (unknown [10.39.195.81]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9E32827C28; Wed, 23 Feb 2022 10:07:26 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id E767618003BA; Wed, 23 Feb 2022 11:07:24 +0100 (CET) Date: Wed, 23 Feb 2022 11:07:24 +0100 From: "Gerd Hoffmann" To: Min Xu Cc: devel@edk2.groups.io, Ard Biesheuvel , Jordan Justen , Brijesh Singh , Erdem Aktas , James Bottomley , Jiewen Yao , Tom Lendacky Subject: Re: [PATCH V6 33/42] OvmfPkg: Update PlatformInitLib for Tdx guest to publish ram regions Message-ID: <20220223100724.5wqr3lmso43n3yhc@sirius.home.kraxel.org> References: <6b6241dda6d4a672e4602ddae095963c0e127edc.1645261991.git.min.m.xu@intel.com> MIME-Version: 1.0 In-Reply-To: <6b6241dda6d4a672e4602ddae095963c0e127edc.1645261991.git.min.m.xu@intel.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kraxel@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi, > Another update is in PlatformAddressWidthInitialization. The physical > address width that Tdx guest supports is either 48 or 52. Hmm. Sure this is correct? 48 is the max _virtual_ address space possible with 4-level paging. The _physical_ address space might be much smaller, like this (kaby lake desktop system): # lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Address sizes: 39 bits physical, 48 bits virtual Byte Order: Little Endian Maybe all TDX-capable Intel CPUs actually have >= 48 bits physical, so this could be fine, but please double-check. thanks, Gerd