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 B600ACE79CF for ; Wed, 20 Sep 2023 12:05:54 +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 2826F1CA24A for ; Wed, 20 Sep 2023 12:05:54 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 1E75198667A for ; Wed, 20 Sep 2023 12:05:54 +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 142DE98666B; Wed, 20 Sep 2023 12:05:54 +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 0709E98666F for ; Wed, 20 Sep 2023 12:05:54 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: 34Fn8exBPQ-taDB9i6m2yw-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695211549; x=1695816349; 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=wwlCOFZiDcAlXmpWDtUmhslEuQg1QYyeroSf+oqjId4=; b=uBLn5DxNeM0eafiO3duDueiqKSWOKSPeqlKTWwC5Lmsv+DIrEBcVdbstfqbja8dp2z xi5LbpHUmaKrRFA6KZ3usy8CK2JJi35AGOKHMttUxYRjwxqdlsURH5Tc1EvHh7mpLVkT NOnmmYsq0KVkyTaqRGAQn/Xw6wwkl7/5siaVRPRNBNnaQ5lJFu6b+QF20GExlDPyLQGy ARx0U8oghcXMIxwoBPUShUxber96H8a4PJ92rsRCjdQl4CYVE8z6rZ/PP5EFAJs4bA9+ o98SaYaRd+pUSCtqa9D8dHzc9a5nV1whXLnsl2PYU+U8Wh4K372Cyruz22ROHOaT+nOW ATjA== X-Gm-Message-State: AOJu0Yxh2FgF9jwp5uejPtYZv8HWAvkqwFzqq8BIk8KN07z4PXqYg0v3 mav9ZCjlCnD2uL1a5p/9aLvthFgnd2GQ9VsxaGFkslztcDNq0gdedIgY2ULyl5wxF01DVVJr9WB Oa5pCz+d5hcku9eVq379NPLo4Yf6F X-Received: by 2002:a17:906:109e:b0:994:4095:3abf with SMTP id u30-20020a170906109e00b0099440953abfmr1845673eju.14.1695211549751; Wed, 20 Sep 2023 05:05:49 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGW17783KghXPmGSkWpE9l0Vh+Xsrgp1KK9uEgJplxrjoutU3u8WGO8ojO4eWOZwX1zezt4rw== X-Received: by 2002:a17:906:109e:b0:994:4095:3abf with SMTP id u30-20020a170906109e00b0099440953abfmr1845659eju.14.1695211549422; Wed, 20 Sep 2023 05:05:49 -0700 (PDT) Date: Wed, 20 Sep 2023 08:05:44 -0400 From: "Michael S. Tsirkin" To: "Zhu, Lingshan" Cc: Parav Pandit , "virtio-dev@lists.oasis-open.org" , Jason Wang Message-ID: <20230920075243-mutt-send-email-mst@kernel.org> References: <213a0f94-cee2-d8c5-3c5d-d2d7fc920e75@intel.com> <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> MIME-Version: 1.0 In-Reply-To: <2f67fb85-2238-9c34-a265-b0f97b7ab7e1@intel.com> 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 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. > 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? > > > > > 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. > > > > 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? -- MST --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org