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 2D53D21954086 for ; Sun, 30 Apr 2017 17:06:57 -0700 (PDT) Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 826F44E4C4; Mon, 1 May 2017 00:06:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 826F44E4C4 Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=lersek@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 826F44E4C4 Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-42.phx2.redhat.com [10.3.116.42]) by smtp.corp.redhat.com (Postfix) with ESMTP id 879B760F85; Mon, 1 May 2017 00:06:55 +0000 (UTC) To: Jordan Justen , edk2-devel-01 References: <20170429201500.18496-1-lersek@redhat.com> <20170429201500.18496-3-lersek@redhat.com> <149351328512.20670.1563878734495138189@jljusten-skl> Cc: Gary Ching-Pang Lin From: Laszlo Ersek Message-ID: <8c838d90-083f-8ab2-c5cd-8874ab4be0f5@redhat.com> Date: Mon, 1 May 2017 02:06:54 +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: <149351328512.20670.1563878734495138189@jljusten-skl> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Mon, 01 May 2017 00:06:56 +0000 (UTC) Subject: Re: [PATCH 2/3] OvmfPkg: introduce FD_SIZE_4MB (mainly) for Windows HCK 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: Mon, 01 May 2017 00:06:57 -0000 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit On 04/30/17 02:48, Jordan Justen wrote: > Today, we give 128k to non-volatile storage, which due to various > reasons results in 56k of variable storage. Personally I already > consider this generous, especially when I look at the 128k size of the > seabios bios.bin. :) I'd like to comment on the seabios analogy; I just needed a bit more time to gather data for this (BZs and build logs, mainly). In RHEL-6, we shipped (and have been shipping) 128KB SeaBIOS binaries. Preparing for RHEL-7.0, we increased the SeaBIOS binary size to 256KB, anticipating future features that would no longer fit into 128KB. This is the BZ for it: https://bugzilla.redhat.com/show_bug.cgi?id=1038604 The exact "seabios-1.7.2.2-5.el7" build, dated 2013-Dec-10, in which the BZ was addressed, is no longer available in our build archives (it was not a released version, just a development build, so that's OK), but "seabios-1.7.2.2-6.el7", i.e. the build right after, is available. At that time, we were still under 128KB: > Total size: 117472 Fixed: 58792 Free: 144672 > (used 44.8% of 256KiB rom) Today, looking at the build log of "seabios-1.10.2-2.el7" (built 2017-Mar-30), I find: > Total size: 149664 Fixed: 75392 Free: 112480 > (used 57.1% of 256KiB rom) Had we not increased the size in advance (via CONFIG_ROM_SIZE), we'd have run out of it over the past ~3.5 years. In OVMF, the address range of the non-volatile area depends on SECFV's size, FVMAIN_COMPACT's size, and on the NV area's size; they come in this order downwards from 4GB. SECFV is safe as-is; it has seen negligible growth in years, and is currently at about 14% in a DEBUG build. I'd like to future-proof the other two (FVMAIN_COMPACT and NV) sizes now, with a large -- approx. seven year -- margin. Thanks Laszlo