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 DE264CE79CF for ; Wed, 20 Sep 2023 12:40:57 +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 438278742B for ; Wed, 20 Sep 2023 12:40:57 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 1B217986671 for ; Wed, 20 Sep 2023 12:40:57 +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 023E698666A; Wed, 20 Sep 2023 12:40:57 +0000 (UTC) Mailing-List: contact virtio-dev-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 E732098666B for ; Wed, 20 Sep 2023 12:40:56 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: P8Ca8NsCNBitjFB8H10LTQ-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695213652; x=1695818452; h=in-reply-to: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=nXJC+vU/acAYUVnhkTJDUUavmo47RfMhNn2aWcAyZoE=; b=o1trL59bXuad/sH04XnDpcU+co4EIx5ty7s28augyQETV0EOzKid6LuGp+tsej3t1y /qStNGBsSPP2w6ffPWcYc13DteOzBjBXJ1ZZsWLzGHkEg8nHLnAUdvFklgOIpwcWUWnK b/aZb0Px07XyzJk89MdN7ooquWLxqqG6ibgwnyQR34iwbHCnSNsbbpagGosgxjyAntCe upY3fq+7lMTafNjMq6ewQg7oj8j1e7KQ2SjFy8Vz3hpYqUPDYKI2zBOOCUaY1Xt0hIWq Lns0ZmgQnDHLVQedkkCp/hoBWKVXRzyvkMuejGKVnxGA6RPj/jy9f1IVT0Te4G45L7t8 WtcA== X-Gm-Message-State: AOJu0Yy1CA0GxT1V0qQ9SEAaIlbdUjMQ+D2+vHAuP1JIMn7DQCIJjrwX MQmn397LJ7B1Ln673Y7uVKnlNU4gu7Y3GmqF8yUUcYH3dnlMkkIX5dMUuPBKmR/n85eRz6E6Zjz tys7HLiJhlwOF2y2akouC04KEZ9bo X-Received: by 2002:a05:6512:280b:b0:4f9:51ac:41eb with SMTP id cf11-20020a056512280b00b004f951ac41ebmr2731747lfb.16.1695213652050; Wed, 20 Sep 2023 05:40:52 -0700 (PDT) X-Google-Smtp-Source: AGHT+IG//mqG5EkRPLdcgapJ9qt0hgsBxkkp3Owyx12oyzQNGjmSQBf9plbYGhaRbmGJr1yk3siPmA== X-Received: by 2002:a05:6512:280b:b0:4f9:51ac:41eb with SMTP id cf11-20020a056512280b00b004f951ac41ebmr2731711lfb.16.1695213651461; Wed, 20 Sep 2023 05:40:51 -0700 (PDT) Date: Wed, 20 Sep 2023 08:40:45 -0400 From: "Michael S. Tsirkin" To: "Zhu, Lingshan" Cc: Parav Pandit , "virtio-dev@lists.oasis-open.org" , Jason Wang Message-ID: <20230920083057-mutt-send-email-mst@kernel.org> References: <5f01772f-eb27-bfe0-7f69-b83fbd90dda0@intel.com> <20230918144312-mutt-send-email-mst@kernel.org> <20230920054836-mutt-send-email-mst@kernel.org> <2f67fb85-2238-9c34-a265-b0f97b7ab7e1@intel.com> <20230920075243-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=us-ascii Content-Disposition: inline Subject: Re: [virtio-dev] Re: [PATCH 0/5] virtio: introduce SUSPEND bit and vq state On Wed, Sep 20, 2023 at 08:16:13PM +0800, Zhu, Lingshan wrote: > > > On 9/20/2023 8:05 PM, Michael S. Tsirkin wrote: > > On Wed, Sep 20, 2023 at 07:22:32PM +0800, Zhu, Lingshan wrote: > > > > > > On 9/20/2023 6:36 PM, Michael S. Tsirkin wrote: > > > > On Wed, Sep 20, 2023 at 02:06:13PM +0800, Zhu, Lingshan wrote: > > > > > On 9/19/2023 2:49 AM, Michael S. Tsirkin wrote: > > > > > > On Mon, Sep 18, 2023 at 06:41:55PM +0000, Parav Pandit wrote: > > > > > > > > Please refer to the code for setting FEATURES_OK. > > > > > > > It wont work when one needs to suspend the device. > > > > > > > There is no point of doing such work over registers as fundamental framework is over the AQ. > > > > > > Well not really. It's over admin commands. When these were built the > > > > > > intent always was that it's possible to use admin commands through > > > > > > another interface, other than admin queue. Is there a problem > > > > > > implementing admin commands over a memory BAR? For example, I can see > > > > > > an "admin command" capability pointing at a BAR where > > > > > > commands are supplied, and using a new group type referring to > > > > > > device itself. > > > > > I am not sure, if a bar cap would be implemented as a proxy for the admin vq > > > > > based live migration. > > > > Not a proxy for a vq in that there's no vq then. > > > I think if the driver sends admin commands through a VF's bar, then > > > VF forwards the admin commands to the PF, it acts like a proxy, > > > or an agent. Anyway it takes admin commands. > > Why send them to the PF? They are controlling the VF anyway. > I think its still too heavy compared to this series proposal it will be on you to prove all the complexity is unnecessary though. > > > > > So the problems we have discussed still exist. > > > > > then the problems of admin vq LM that we have > > > > > discussed > > > > > still exist. > > > > I freely admit the finer points of this extended flamewar have been lost > > > > on me, and I wager I'm not the only one. I thought you wanted to migrate > > > > the device just by accessing the device itself (e.g. the VF) without > > > > accessing other devices (e.g. the PF), while Parav wants it in a > > > > separate device so the whole of the device itself can passed through to > > > > guest. Isn't this, fundamentally, the issue? > > > we are implementing basic facilities for live migration. > > > > > > We have pointed out lots of issues, there are many discussions with > > > Jason and Parav about the problems in migration by admin vq, for example: > > > security, QOS and nested. > > /me shrugs > > Thanks for the summary I guess. Same applies to almost any proposal. > > What would help make progress is an explanation why this has grown into > > a megathread. Do you understand Parav's thoughts well enough to > > summarize them? > as far as I see, I don't see admin vq as must for live migration. > and it does not serve nested for sure. > > > > > > > the bar is only a proxy, doesn't fix anything. and even larger > > > > > side channel attacking surface: vf-->pf-->vf > > > > In this model there's no pf. BAR belongs to vf itself > > > > and you submit commands for the VF through its BAR. > > > > Just separate from the pci config space. > > > If using the bar to process admin commands, > > > is this solution too heavy compared to my proposal in this series? > > somewhat - because it's more comprehensive - you can actually > > migrate a device using it. > > this series just begins to define how to poke at some > > of the vq state - it's a subset of the necessary functionality. > > > > And it will give you a bunch of side benefits, such as > > support for legacy compat commands that were merged. > next version will include in-flight descriptors and dirty page tracking. what we don't need is another version of this megathread. which it sounds like you intend to restart? nor do I cherish maintaining two independent mechanisms for doing the same thing in the spec. all of the above is already in parav's patchset so you guys should find a way to work together rather than compete? > I failed to process the comments for legacy. > legacy devices are defined by code than the spec, if wants to migrate legacy > devices, maybe working on QEMU first that is not much in the way of addressing, just saying go pound sand. the functionality has already been accepted by the TC though I don't know what you are trying to say here. that we should drop it from spec? > > > > > > > > > > The whole attacking surface discussion is also puzzling. We either are > > > > or are not discussing confidential computing/TDI. I couldn't figure > > > > it out. This needs a separate thread I think. > > > I agree confidential computing is out of spec. Parva mentioned TDISP and > > > even > > > in TDISP spec, it explicitly defined some attacking model, and PF is an > > > example. > > > > > > It is out of spec anyway. > > OK so we are ignoring TDISP applications for now? Everyone agrees on > > that? > sure > > --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org