From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 EA23D21A1348B for ; Thu, 11 May 2017 13:14:37 -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 3BF083B708; Thu, 11 May 2017 20:14:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 3BF083B708 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=lersek@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 3BF083B708 Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-15.phx2.redhat.com [10.3.116.15]) by smtp.corp.redhat.com (Postfix) with ESMTP id B84557E227; Thu, 11 May 2017 20:14:35 +0000 (UTC) To: Jordan Justen , Brijesh Singh , edk2-devel@lists.01.org References: <1494454162-9940-1-git-send-email-brijesh.singh@amd.com> <1494454162-9940-7-git-send-email-brijesh.singh@amd.com> <1ebdde6a-bad7-ed9a-b2af-7334477c8ae3@redhat.com> <149452462682.9607.8151737434916832513@jljusten-skl.jf.intel.com> Cc: Thomas.Lendacky@amd.com, Jiewen Yao , leo.duran@amd.com From: Laszlo Ersek Message-ID: Date: Thu, 11 May 2017 22:14:34 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <149452462682.9607.8151737434916832513@jljusten-skl.jf.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 [10.5.110.30]); Thu, 11 May 2017 20:14:37 +0000 (UTC) Subject: Re: [RFC v4 06/13] OvmfPkg:AmdSevDxe: add AmdSevDxe driver X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 May 2017 20:14:38 -0000 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit On 05/11/17 19:43, Jordan Justen wrote: > On 2017-05-11 08:53:39, Laszlo Ersek wrote: >> (5) Please mention that the driver is being added to the APRIORI DXE >> file for a separate reason as well (not just for the early clearing of >> the C bit on MMIO/NonExistent): OvmfPkg's DXE phase modules that tailor >> their behavior to SEV presence will assume that the IOMMU protocol >> exported by this driver is available *at once*. > > What other code depends on this being run apriori? Minimally, every module that is a client of the DXE-phase fw-cfg library instance. That library instance uses the EdkII IOMMU protocol for allocating and freeing the non-encrypted bounce buffer needed for the fw_cfg DMA transfer. The protocol is only used / needed when SEV is detected. Thanks Laszlo