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 3F553C48BD4 for ; Tue, 25 Jun 2019 16:52:05 +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 179E2204FD for ; Tue, 25 Jun 2019 16:52:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 179E2204FD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=birkelund.eu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:34050 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hfofs-0001F6-8R for qemu-devel@archiver.kernel.org; Tue, 25 Jun 2019 12:52:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51243) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hfoZX-0006KT-CY for qemu-devel@nongnu.org; Tue, 25 Jun 2019 12:45:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hfoZW-000064-7f for qemu-devel@nongnu.org; Tue, 25 Jun 2019 12:45:31 -0400 Received: from charlie.dont.surf ([128.199.63.193]:44872) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hfoZT-0008RN-FA; Tue, 25 Jun 2019 12:45:27 -0400 Received: from apples.localdomain (ip-5-186-120-196.cgn.fibianet.dk [5.186.120.196]) by charlie.dont.surf (Postfix) with ESMTPSA id C33F7BF988; Tue, 25 Jun 2019 16:45:22 +0000 (UTC) Date: Tue, 25 Jun 2019 18:45:19 +0200 From: Klaus Birkelund To: Kevin Wolf Message-ID: <20190625164445.GA21148@apples.localdomain> Mail-Followup-To: Kevin Wolf , Laszlo Ersek , qemu-devel@nongnu.org, Keith Busch , Max Reitz , qemu-block@nongnu.org, Markus Armbruster References: <20190617081205.GA26990@apples.localdomain> <20190624080154.GA4263@apples.localdomain> <20190624101828.GC12855@linux.fritz.box> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190624101828.GC12855@linux.fritz.box> User-Agent: Mutt/1.12.0 (2019-05-25) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 128.199.63.193 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: qemu-block@nongnu.org, Markus Armbruster , qemu-devel@nongnu.org, Keith Busch , Max Reitz , Laszlo Ersek Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Jun 24, 2019 at 12:18:45PM +0200, 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. > > The thing that is special here is that -device nvme is already a block > device by itself that can take a drive property. So how does this play > together? Can I choose to either specify a drive directly for the nvme > device or nvme-ns devices, but when I do both, I will get an error? What > happens if I don't specify a drive for nvme, but also don't add nvme-ns > devices? > Hi Kevin, Yes, the nvme device is already a block device. My current patch removes that property from the nvme device. I guess this breaks backward compatibiltiy. We could accept a drive for the nvme device only if no nvme-ns devices are configured and connected on the bus. I'm not entirely sure on the spec, but my gut tells me that an nvme device without any namespaces is technically a valid device, although it is a bit useless. I will post my patch (as part of a larger series) and we can discuss it there. Thanks for the feedback! Klaus