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 F2E69C19F2A for ; Thu, 4 Aug 2022 15:21:29 +0000 (UTC) Received: from localhost ([::1]:59270 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oJcfA-0004Wb-T3 for qemu-devel@archiver.kernel.org; Thu, 04 Aug 2022 11:21:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52228) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oJcc2-0001se-93 for qemu-devel@nongnu.org; Thu, 04 Aug 2022 11:18:14 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:57164) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oJcby-0006Fk-I4 for qemu-devel@nongnu.org; Thu, 04 Aug 2022 11:18:12 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1659626289; 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=wrHFLP4UagrNY/sN+cUTXX68z4eieZAxwehEA6ugLO0=; b=XhAuKCgcZ8B3f+paZP3Jy58xigljeo2d9wvrhwUusfGyUA0KgOS5SISIoZsOOqCpaZaU5V tHWO8Vvxvh+2GNh9a/8R7dv0YshUSjpMUm/RKwNHQJ2xJaJfaGuiN4x+N9UJTZaxO+ee3z SaGoZVZ1NYgPwpsa/8kwkvo2i5irytY= 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-362-4qvWvm8xMkWmRLZTIJXFDA-1; Thu, 04 Aug 2022 11:18:06 -0400 X-MC-Unique: 4qvWvm8xMkWmRLZTIJXFDA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 98F7C3C0D870; Thu, 4 Aug 2022 15:18:05 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.223]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D981140CF8EA; Thu, 4 Aug 2022 15:18:01 +0000 (UTC) Date: Thu, 4 Aug 2022 16:17:59 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Cc: Peter Maydell , Kevin Wolf , Hao Wu , richard.henderson@linaro.org, qemu-arm@nongnu.org, qemu-devel@nongnu.org, venture@google.com, Avi.Fishman@nuvoton.com, kfting@nuvoton.com, hskinnemoen@google.com, f4bug@amsat.org, bin.meng@windriver.com, qemu-block@nongnu.org, thuth@redhat.com, Hanna Reitz Subject: Re: [PATCH v5 5/8] blockdev: Add a new IF type IF_OTHER Message-ID: References: <20220714182836.89602-1-wuhaotsh@google.com> <20220714182836.89602-6-wuhaotsh@google.com> <87ilnuda33.fsf@pond.sub.org> <877d3odpm8.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <877d3odpm8.fsf@pond.sub.org> User-Agent: Mutt/2.2.6 (2022-06-05) X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 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_NONE=-0.0001, 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?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Aug 04, 2022 at 04:56:15PM +0200, Markus Armbruster wrote: > Daniel P. Berrangé writes: > > > On Thu, Jul 28, 2022 at 10:46:35AM +0100, Peter Maydell wrote: > >> On Wed, 27 Jul 2022 at 20:03, Kevin Wolf wrote: > >> > > >> > Am 18.07.2022 um 11:49 hat Markus Armbruster geschrieben: > >> > > An OTP device isn't really a parallel flash, and neither are eFuses. > >> > > More fast-and-lose use of IF_PFLASH may exist in the tree, and maybe of > >> > > other interface types, too. > >> > > > >> > > This patch introduces IF_OTHER. The patch after next uses it for an > >> > > EEPROM device. > >> > > > >> > > Do we want IF_OTHER? > >> > > >> > What would the semantics even be? Any block device that doesn't pick up > >> > a different category may pick up IF_OTHER backends? > >> > > >> > It certainly feels like a strange interface to ask for "other" disk and > >> > then getting as surprise what this other thing might be. It's > >> > essentially the same as having an explicit '-device other', and I > >> > suppose most people would find that strange. > >> > > >> > > If no, I guess we get to abuse IF_PFLASH some more. > >> > > > >> > > If yes, I guess we should use IF_PFLASH only for actual parallel flash > >> > > memory going forward. Cleaning up existing abuse of IF_PFLASH may not > >> > > be worth the trouble, though. > >> > > > >> > > Thoughts? > >> > > >> > If the existing types aren't good enough (I don't have an opinion on > >> > whether IF_PFLASH is a good match), let's add a new one. But a specific > >> > new one, not just "other". > >> > >> I think the common thread is "this isn't what anybody actually thinks > >> of as being a 'disk', but we would like to back it with a block device > >> anyway". That can cover a fair range of possibilities... > > > > Given that, do we even want/have to use -drive for this ? We can use > > -blockdev for the backend and reference that from any -device we want > > to create, and leave -drive out of the picture entirely > > -drive is our only means to configure onboard devices. > > We've talked about better means a few times, but no conclusions. I can > dig up pointers, if you're interested. For onboard pflash with x86, we've just got properties against the machine that we can point to a blockdev. 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 :|