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 9BD99C433EF for ; Mon, 31 Jan 2022 16:27:07 +0000 (UTC) Received: from localhost ([::1]:32850 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nEZWE-0003l6-KI for qemu-devel@archiver.kernel.org; Mon, 31 Jan 2022 11:27:06 -0500 Received: from eggs.gnu.org ([209.51.188.92]:57634) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nEZ5E-0004MX-DH for qemu-devel@nongnu.org; Mon, 31 Jan 2022 10:59:12 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:54114) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nEZ5C-0004Ap-Kz for qemu-devel@nongnu.org; Mon, 31 Jan 2022 10:59:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643644750; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EjMHoVlehjoyXWpnOv/NbqHJ7jV0xeOV5EsUpJGXymM=; b=BifS5XEDKjAhkjNZiyOL1e1f152oRUy+OqbTMcvt0YqpAQiyesUc+OcmpuIO81fQNXhYRq y1E7nL3QjtQYqXApNc0r7rX+jt2Q/57haK1Wzs3haTb2alb4IQZS5PQc/pqpzS2wp9VTsy uWpCsdHmn22QF4y2c2UXTXsDU7If+9E= 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-665-7Xg3C3HNN9u4jFZAUGAT_Q-1; Mon, 31 Jan 2022 10:59:06 -0500 X-MC-Unique: 7Xg3C3HNN9u4jFZAUGAT_Q-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1FF211018722; Mon, 31 Jan 2022 15:59:05 +0000 (UTC) Received: from paraplu (unknown [10.39.195.135]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2F6E8798C0; Mon, 31 Jan 2022 15:58:34 +0000 (UTC) Date: Mon, 31 Jan 2022 16:58:31 +0100 From: Kashyap Chamarthy To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Subject: Re: [PATCH v2] docs: expand firmware descriptor to allow flash without NVRAM Message-ID: References: <20220131125509.170307-1-berrange@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kchamart@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=kchamart@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=-0.088, 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_H2=-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: , Cc: libvir-list@redhat.com, qemu-devel@nongnu.org, Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Jan 31, 2022 at 03:35:02PM +0000, Daniel P. Berrangé wrote: > On Mon, Jan 31, 2022 at 04:21:36PM +0100, Kashyap Chamarthy wrote: > > On Mon, Jan 31, 2022 at 02:36:46PM +0000, Daniel P. Berrangé wrote: [...] > > > The firmware can be provided in qcow2 format too, so if really > > > concerned, just create a qcow2 file with a backing store pointing > > > to the readonly master, so you're only paying the price of the > > > delta for any guest VARs writes. That's more efficient than what > > > we do today with copying the separate raw format VARS.fd file. > > > > That's nice, I didn't know the qcow2 possibility in this context. For > > some reason I assumed the file format always has to be raw here. Your > > qcow2 point above should be documented, if it isn't already. Although > > I don't know the right place for it. > > There's already a format field in the descriptor, but even if the > firmware is distributed as raw, libvirt can choose to put qcow2 > overlay on it, as its all configured with -blockdev Ah, understood. I should've first checked the spec to look for the @format field. For others reading the thread, the @format bit is located here infirmware.json: [...] # @FirmwareFlashFile: # # Defines common properties that are necessary for loading a firmware # file into a pflash chip. The corresponding QEMU command line option is # "-drive file=@filename,format=@format". Note however that the # option-argument shown here is incomplete; it is completed under # @FirmwareMappingFlash. # # @filename: Specifies the filename on the host filesystem where the # firmware file can be found. # # @format: Specifies the block format of the file pointed-to by # @filename, such as @raw or @qcow2. [...] -- /kashyap