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 0549921A16ECB for ; Fri, 2 Jun 2017 07:55:24 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C011A80F99; Fri, 2 Jun 2017 14:56:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com C011A80F99 Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=kraxel@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com C011A80F99 Received: from nilsson.home.kraxel.org (ovpn-117-95.ams2.redhat.com [10.36.117.95]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8477077C0D; Fri, 2 Jun 2017 14:56:23 +0000 (UTC) Received: by nilsson.home.kraxel.org (Postfix, from userid 500) id 4D7B380E1F; Fri, 2 Jun 2017 16:56:22 +0200 (CEST) Message-ID: <1496415382.16895.4.camel@redhat.com> From: Gerd Hoffmann To: Laszlo Ersek , Ard Biesheuvel , edk2-devel@lists.01.org Cc: leif.lindholm@linaro.org, jordan.l.justen@intel.com, Shannon Zhao , "Michael S. Tsirkin" , Igor Mammedov , qemu devel list , gengdongjiu , Drew Jones Date: Fri, 02 Jun 2017 16:56:22 +0200 In-Reply-To: References: <20170601112241.2580-1-ard.biesheuvel@linaro.org> Mime-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Fri, 02 Jun 2017 14:56:26 +0000 (UTC) Subject: Re: [RFC PATCH] OvmfPkg/AcpiPlatformDxe: lift 4 GB alloc limit for modern ACPI systems 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: Fri, 02 Jun 2017 14:55:24 -0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi, >=C2=A0The reason is that old firmware is allowed to fail on new QEMU > (regardless of machine type). Example: the WRITE_POINTER command, > originally introduced for VMGENID. If you run a SeaBIOS binary > without > WRITE_POINTER support, in a QEMU VM with "-device vmgenid", the > device > will not work. Old seabios will work just fine on new qemu as long as you don't use the vmgenid device. Only when using new features (which require firmware support) new seabios is needed, and usually we update seabios for that reason. We want the new features be usable of course. But in general there are no lockstep updates for qemu and seabios (any more). > And this patch is actually that case, because the new fw would > allocate > blobs with such 8-byte addresses that might not fit into 32-bit blob > fields. I think ovmf simply checking whenever the pointer fields are 32bit or 64bit, then doing allocations accordingly (as Igor suggested) would be the best. Why ask qemu for a hint when ovmf can figure on its own?=20 That adds a new interface and new config knobs for IMO no good reason. cheers, Gerd