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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4B8A0C433EF for ; Thu, 31 Mar 2022 09:07:09 +0000 (UTC) Received: from localhost ([::1]:43348 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nZqlo-00049e-8f for qemu-devel@archiver.kernel.org; Thu, 31 Mar 2022 05:07:08 -0400 Received: from eggs.gnu.org ([209.51.188.92]:37604) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nZqfn-0007UR-LM for qemu-devel@nongnu.org; Thu, 31 Mar 2022 05:00:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:50721) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nZqfl-0004Bq-9b for qemu-devel@nongnu.org; Thu, 31 Mar 2022 05:00:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1648717252; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BuqkkGgGXCxzRL6yOlBr2HGJjk2midZHSoM5E+pGFME=; b=awxtjN0e6jNAKlQNcrF9yCyMvQdu9LNyyZ2eVZm+BxB6bXAywsGMsL+HhPEgm7qj6o3Moe Xf7qm0ojnJCotgT6MIc/pFG2zekCps59IDdsSE9+vA9OInCJ+3rhF2J6CN77yc2j5waUh7 ZqfriAQydMjGQr1DtwC7AWMzGsJROR0= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-635-o3KpGjjbMPSV2wJwlq0-0g-1; Thu, 31 Mar 2022 05:00:48 -0400 X-MC-Unique: o3KpGjjbMPSV2wJwlq0-0g-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6020E3C11C81; Thu, 31 Mar 2022 09:00:47 +0000 (UTC) Received: from redhat.com (unknown [10.39.194.58]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2B71D1400C2B; Thu, 31 Mar 2022 09:00:44 +0000 (UTC) Date: Thu, 31 Mar 2022 10:00:41 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Xiaoyao Li Subject: Re: [RFC PATCH v3 17/36] pflash_cfi01/tdx: Introduce ram_mode of pflash for TDVF Message-ID: References: <20220317135913.2166202-1-xiaoyao.li@intel.com> <20220317135913.2166202-18-xiaoyao.li@intel.com> <7a8233e4-0cae-b05a-7931-695a7ee87fc9@intel.com> <1d5b0192-75ef-49ad-dc47-cfc0c3c63455@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1d5b0192-75ef-49ad-dc47-cfc0c3c63455@intel.com> User-Agent: Mutt/2.1.5 (2021-12-30) X-Scanned-By: MIMEDefang 2.85 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: isaku.yamahata@intel.com, Marcelo Tosatti , kvm@vger.kernel.org, "Michael S. Tsirkin" , Connor Kuehl , Eric Blake , Cornelia Huck , Richard Henderson , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , qemu-devel@nongnu.org, Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Gerd Hoffmann , seanjc@google.com, erdemaktas@google.com, Paolo Bonzini , Laszlo Ersek Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Mar 31, 2022 at 04:51:27PM +0800, Xiaoyao Li wrote: > On 3/22/2022 5:27 PM, Daniel P. Berrangé wrote: > ... > > IMHO the AmdSev build for OVMF gets this right by entirely disabling > > the split OVMF_CODE.fd vs OVMF_VARS.fd, and just having a single > > OVMF.fd file that is exposed read-only to the guest. > > > > This is further represented in $QEMU.git/docs/interop/firmware.json > > by marking the firmware as 'stateless', which apps like libvirt will > > use to figure out what QEMU command line to pick. > > Hi Daniel, > > I don't play with AMD SEV and I'm not sure if AMD SEV requires only single > OVMF.fd. But IIUC, from edk2 > > commit 437eb3f7a8db ("OvmfPkg/QemuFlashFvbServicesRuntimeDxe: Bypass flash > detection with SEV-ES") > > , AMD SEV(-ES) does support NVRAM via proactive VMGEXIT MMIO > QemuFlashWrite(). If so, AMD SEV seems to be able to support split OVMF, > right? Note that while the traditional OvmfPkg build can be used with SEV/SEV-ES, this is not viable for measured boot, as it uses the NVRAM whose content is not measured. I was specifically referring to the OvmfPkg/AmdSev build which doesn't use seprate NVRAM, and has no variables persistence. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|