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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 14CDCC48BD7 for ; Tue, 25 Jun 2019 07:25:44 +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 E2A162085A for ; Tue, 25 Jun 2019 07:25:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E2A162085A 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]:57114 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hffpn-0005gw-3A for qemu-devel@archiver.kernel.org; Tue, 25 Jun 2019 03:25:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35539) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hffoo-0004o5-Ul for qemu-devel@nongnu.org; Tue, 25 Jun 2019 03:24:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hffon-0006p7-A0 for qemu-devel@nongnu.org; Tue, 25 Jun 2019 03:24:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49560) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hffok-0006ll-JG; Tue, 25 Jun 2019 03:24:38 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8FA7E81F35; Tue, 25 Jun 2019 07:24:37 +0000 (UTC) Received: from localhost.localdomain (ovpn-117-23.ams2.redhat.com [10.36.117.23]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2BE9D600C7; Tue, 25 Jun 2019 07:24:32 +0000 (UTC) Date: Tue, 25 Jun 2019 09:24:30 +0200 From: Kevin Wolf To: Laszlo Ersek Message-ID: <20190625072430.GA5187@localhost.localdomain> References: <20190617081205.GA26990@apples.localdomain> <20190624080154.GA4263@apples.localdomain> <20190624101828.GC12855@linux.fritz.box> <3571317f-84c2-8649-ba63-0e6508679b05@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3571317f-84c2-8649-ba63-0e6508679b05@redhat.com> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Tue, 25 Jun 2019 07:24:37 +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] [Qemu-block] [RFC] nvme: how to support multiple namespaces 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: Keith Busch , Markus Armbruster , qemu-devel@nongnu.org, qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 24.06.2019 um 22:46 hat Laszlo Ersek geschrieben: > On 06/24/19 12:18, Kevin Wolf wrote: > > Am 24.06.2019 um 10:01 hat Klaus Birkelund geschrieben: > >> On Thu, Jun 20, 2019 at 05:37:24PM +0200, Laszlo Ersek wrote: > >>> On 06/17/19 10:12, Klaus Birkelund wrote: > >>>> Hi all, > >>>> > >>>> I'm thinking about how to support multiple namespaces in the NVMe > >>>> device. My first idea was to add a "namespaces" property array to the > >>>> device that references blockdevs, but as Laszlo writes below, this might > >>>> not be the best idea. It also makes it troublesome to add per-namespace > >>>> parameters (which is something I will be required to do for other > >>>> reasons). Some of you might remember my first attempt at this that > >>>> included adding a new block driver (derived from raw) that could be > >>>> given certain parameters that would then be stored in the image. But I > >>>> understand that this is a no-go, and I can see why. > >>>> > >>>> I guess the optimal way would be such that the parameters was something > >>>> like: > >>>> > >>>> -blockdev raw,node-name=blk_ns1,file.driver=file,file.filename=blk_ns1.img > >>>> -blockdev raw,node-name=blk_ns2,file.driver=file,file.filename=blk_ns2.img > >>>> -device nvme-ns,drive=blk_ns1,ns-specific-options (nsfeat,mc,dlfeat)... > >>>> -device nvme-ns,drive=blk_ns2,... > >>>> -device nvme,... > >>>> > >>>> My question is how to state the parent/child relationship between the > >>>> nvme and nvme-ns devices. I've been looking at how ide and virtio does > >>>> this, and maybe a "bus" is the right way to go? > >>> > >>> I've added Markus to the address list, because of this question. No > >>> other (new) comments from me on the thread starter at this time, just > >>> keeping the full context. > >>> > >> > >> Hi all, > >> > >> I've succesfully implemented this by introducing a new 'nvme-ns' device > >> model. The nvme device creates a bus named from the device id ('id' > >> parameter) and the nvme-ns devices are then registered on this. > >> > >> This results in an nvme device being creates like this (two namespaces > >> example): > >> > >> -drive file=nvme0n1.img,if=none,id=disk1 > >> -drive file=nvme0n2.img,if=none,id=disk2 > >> -device nvme,serial=deadbeef,id=nvme0 > >> -device nvme-ns,drive=disk1,bus=nvme0,nsid=1 > >> -device nvme-ns,drive=disk2,bus=nvme0,nsid=2 > >> > >> How does that look as a way forward? > > > > This looks very similar to what other devices do (one bus controller > > that has multiple devices on its but), so I like it. > > +1 > > Also, I believe it's more modern nowadays to express the same example > with "blockdev" syntax, rather than "drive". (Not that I could suggest > the exact spelling for that :)) I don't expect the modern syntax to > behave differently, I just guess it's better to stick with the new in > examples / commit messages etc. As this example uses only raw files, it's actually pretty simple: -blockdev driver=file,filename=nvme0n1.img,node-name=disk1 -blockdev driver=file,filename=nvme0n2.img,node-name=disk2 The -device options stay the same, their drive=... value just refers to the node-name now. (-drive IDs and node-names have a shared namespace, so this is unambiguous.) For the sake of completeness, if nvme0n1.img were actually a qcow2 image, you would add a second -blockdev for the format layer: -blockdev driver=file,filename=nvme0n1.img,node-name=disk1-file -blockdev driver=qcow2,file=disk1-file,node-name=disk1 Kevin