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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CAE8DC3A589 for ; Thu, 15 Aug 2019 14:21:54 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9FAE62084D for ; Thu, 15 Aug 2019 14:21:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9FAE62084D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42404 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hyGdV-00059D-H9 for qemu-devel@archiver.kernel.org; Thu, 15 Aug 2019 10:21:53 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54014) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hyGcR-0004cm-T4 for qemu-devel@nongnu.org; Thu, 15 Aug 2019 10:20:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hyGcL-0002YV-Uq for qemu-devel@nongnu.org; Thu, 15 Aug 2019 10:20:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42930) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hyGcA-0002TR-Il; Thu, 15 Aug 2019 10:20:30 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D2068317528E; Thu, 15 Aug 2019 14:20:29 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-117-142.ams2.redhat.com [10.36.117.142]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 15BD043FD2; Thu, 15 Aug 2019 14:20:26 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id A50251EB6C82; Thu, 15 Aug 2019 16:18:16 +0200 (CEST) From: Markus Armbruster To: Kevin Wolf References: <20190814202219.1870-1-mlevitsk@redhat.com> <20190815091039.GA7415@linux.fritz.box> Date: Thu, 15 Aug 2019 16:18:16 +0200 In-Reply-To: <20190815091039.GA7415@linux.fritz.box> (Kevin Wolf's message of "Thu, 15 Aug 2019 11:10:39 +0200") Message-ID: <87y2zuy0k7.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Thu, 15 Aug 2019 14:20:29 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH 00/13] RFC: luks/encrypted qcow2 key management X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fam Zheng , "Daniel P. =?utf-8?Q?Berrang=C3=A9?=" , qemu-block@nongnu.org, qemu-devel@nongnu.org, Max Reitz , Stefan Hajnoczi , Maxim Levitsky Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Kevin Wolf writes: > Am 14.08.2019 um 23:08 hat Eric Blake geschrieben: >> On 8/14/19 3:22 PM, Maxim Levitsky wrote: >> >> > This is an issue that was raised today on IRC with Kevin Wolf. Really thanks >> > for the idea! >> > >> > We agreed that this new qmp interface should take the same options as >> > blockdev-create does, however since we want to be able to edit the encryption >> > slots separately, this implies that we sort of need to allow this on creation >> > time as well. >> > >> > Also the BlockdevCreateOptions is a union, which is specialized by the driver name >> > which is great for creation, but for update, the driver name is already known, >> > and thus the user should not be forced to pass it again. >> > However qmp doesn't seem to support union type guessing based on actual fields >> > given (this might not be desired either), which complicates this somewhat. >> >> Does the idea of a union type with a default value for the discriminator >> help? Maybe we have a discriminator which defaults to 'auto', and add a >> union branch 'auto':'any'. During creation, if the "driver":"auto" >> branch is selected (usually implicitly by omitting "driver", but also >> possible explicitly), the creation attempt is rejected as invalid >> regardless of the contents of the remaining 'any'. But during amend >> usage, if the 'auto' branch is selected, we then add in the proper >> "driver":"xyz" and reparse the QAPI object to determine if the remaining >> fields in 'any' still meet the specification for the required driver branch. >> >> This idea may still require some tweaks to the QAPI generator, but it's >> the best I can come up with for a way to parse an arbitrary JSON object >> with unknown validation, then reparse it again after adding more >> information that would constrain the parse differently. > > Feels like this would be a lot of code just to allow the client to omit > passing a value that it knows anyway. If this were a human interface, I > could understand the desire to make commands less verbose, but for QMP I > honestly don't see the point when it's not trivial. Seconded.