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 ws5-mx01.kavi.com (ws5-mx01.kavi.com [34.193.7.191]) (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 A3A3FC001E0 for ; Mon, 23 Oct 2023 11:35:34 +0000 (UTC) Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by ws5-mx01.kavi.com (Postfix) with ESMTP id 0D05C74106 for ; Mon, 23 Oct 2023 11:35:34 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id D777A986679 for ; Mon, 23 Oct 2023 11:35:33 +0000 (UTC) Received: from host09.ws5.connectedcommunity.org (host09.ws5.connectedcommunity.org [10.110.1.97]) by lists.oasis-open.org (Postfix) with QMQP id BC14298666C; Mon, 23 Oct 2023 11:35:33 +0000 (UTC) Mailing-List: contact virtio-comment-help@lists.oasis-open.org; run by ezmlm List-ID: Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id C7F6798666D for ; Mon, 23 Oct 2023 11:34:06 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: NJ6Rz_vqNBqy_-J7yccPAQ-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698060838; x=1698665638; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=6IQJiLUb8tFsZJyorke4h4h1oGr/urp4hrqYM4trhbU=; b=Gd+c082g8LFGq8OQj2nBxtCaIpng7bJ6aZPLjVAxRCluHPaA88oLeV9hYWzhfLts70 ikfV6Ai1zxj5KHkd/ylKSjjd9duEEAAIMyBQ6y8XFj4E/csmOQyVW1iJOBfC5ftIblNf i9g3XWQQHGOqacLN027bjrl0c+T2t1YrS7LIEXLR7SULkrncUKkwGE58Yk+C1+5IYQg/ VHUo8BuJkG+gnY4CpUCaNMpVM3HmhUBOOsIes6vN1mC/0PZGveysgbGrrckR6o0qulRA cTsuKPmawhX3Qhbf3bTeGcZTSDdzqwpruQ0SJkMONn4PCGx/Na+m4bmqfxyk0cv4+HU6 ZmBw== X-Gm-Message-State: AOJu0YxCv86haSAc3nFs+ZYql83t/GTLSc4mVwoVX1+LLP7So4xQ0UjC MMWWk12qMcS+wwe+EJ68W7drrkOwF0G1NzZ3NfcsihmUGQG9Q2JHKl699+7Y5Qj0aCI0qqudicH vjxMAo85YUuvXmz0PWgVa3zKC4wD9CFZYvg== X-Received: by 2002:a05:600c:45ca:b0:408:575e:f24f with SMTP id s10-20020a05600c45ca00b00408575ef24fmr4559853wmo.28.1698060838228; Mon, 23 Oct 2023 04:33:58 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHjyMg3uGiLxv2+FovlZOuK56Ox1cIid0Ei5300ZYlej88dwqA2eJmhmKmen88zdPfK8azhpw== X-Received: by 2002:a05:600c:45ca:b0:408:575e:f24f with SMTP id s10-20020a05600c45ca00b00408575ef24fmr4559835wmo.28.1698060837791; Mon, 23 Oct 2023 04:33:57 -0700 (PDT) Date: Mon, 23 Oct 2023 07:33:48 -0400 From: "Michael S. Tsirkin" To: Jason Wang Cc: "Zhu, Lingshan" , Parav Pandit , "virtio-comment@lists.oasis-open.org" , "cohuck@redhat.com" , "sburla@marvell.com" , Shahaf Shuler , Maor Gottlieb , Yishai Hadas Message-ID: <20231023073324-mutt-send-email-mst@kernel.org> References: <7bc82c01-19ad-4180-914b-9304e10ef7c3@intel.com> <20231019051406-mutt-send-email-mst@kernel.org> <20231020053534-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Subject: Re: [virtio-comment] Re: [PATCH v1 3/8] device-context: Define the device context fields for device migration On Mon, Oct 23, 2023 at 11:53:50AM +0800, Jason Wang wrote: > On Fri, Oct 20, 2023 at 5:41 PM Michael S. Tsirkin wrote: > > > > On Fri, Oct 20, 2023 at 05:31:01PM +0800, Zhu, Lingshan wrote: > > > > > > > > > On 10/19/2023 6:33 PM, Parav Pandit wrote: > > > > > From: Zhu, Lingshan > > > > > Sent: Thursday, October 19, 2023 2:48 PM > > > > > > > > > > On 10/19/2023 5:14 PM, Michael S. Tsirkin wrote: > > > > > > On Thu, Oct 19, 2023 at 09:13:16AM +0000, Parav Pandit wrote: > > > > > > > > Oh, really? Quite interesting, do you want to move all config space > > > > > > > > fields in VF to admin vq? Have a plan? > > > > > > > Not in my plan for spec 1.4 time frame. > > > > > > > I do not want to divert the discussion, would like to focus on device > > > > > migration phases. > > > > > > > Lets please discuss in some other dedicated thread. > > > > > > Possibly, if there's a way to send admin commands to vf itself then > > > > > > Lingshan will be happy? > > > > > still need to prove why admin commands are better than registers. > > > > Virtio spec development is not proof based approach. Please stop asking for it. > > > > > > > > I tried my best to have technical answer in [1]. > > > > I explained that registers simply do not work for passthrough mode > > > > (if this is what you are asking when you are asking prove its better). > > > > They can work for non_passthrough mediated mode. > > > > > > > > A member device may do admin commands using registers. Michael and I are discussing presently in the same thread. > > > > > > > > Since there are multiple things to be done for device migration, dedicated register set for each functionality do not scale well, hard to maintain and extend. > > > > A register holding a command content make sense. > > > > > > > > Now, with that, if this can be useful only for non_passthrough, I made humble request to transport them using AQ, this way, you get all benefits of AQ. > > > > And trying to understand, why AQ cannot possible or inferior? > > > > > > > > If you have commands like suspend/resume device, register or queue transport simply don’t work, because it's wrong to bifurcate the device with such weird API. > > > > If you want to biferacate for mediation software, it probably makes sense to operate at each VQ level, config space level. Such are very different commands than passthrough. > > > > I think vdpa has demonstrated that very well on how to do specific work for specific device type. So some of those work can be done using AQ. > > > > > > > > [1] https://lore.kernel.org/virtio-comment/870ace02-f99c-4582-932f-bd103362dae9@intel.com/T/#m37743aa924536d0256d6b3b8e83a11c750f28794 > > > We have been through your statement for many times. > > > This is not about how many times you repeated, if you think this is true, > > > you need to prove that with solid evidence. > > > > > > > > > For pass-through, I still recommend you to take a reference of current > > > virito-pci implementation, it works for pass-through, right? > > > > Current migration implementation in e.g. QEMU? It does but it > > traps data path accesses. That, I think we can agree, > > should not be the only option to migrate. > > > > > For scale, I already told you for many times that they are per-device > > > facilities. How can a per-device facility not scale? > > > vDPA works fine on config space. > > > > > > So, if you still insist admin vq is better than config space like in other > > > thread you have concluded, you may imply that config space interfaces should > > > be re-factored to admin vq. > > > > There are good arguments that yes, virtio needs a transport for config space > > that is DMA based as opposed to memory mapped based. This is one of the > > things all vendors seem to prefer in IDPF so virtio should have the option. > > Then it is the transport vq or transport over adminq proposal? > > Thanks That's one way to do it, yes. -- MST This publicly archived list offers a means to provide input to the OASIS Virtual I/O Device (VIRTIO) TC. In order to verify user consent to the Feedback License terms and to minimize spam in the list archive, subscription is required before posting. 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