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 45F70EE021A for ; Fri, 15 Sep 2023 04:28:43 +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 621472B137 for ; Fri, 15 Sep 2023 04:28:42 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 07E7298666C for ; Fri, 15 Sep 2023 04:28:42 +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 C35DF983DE4; Fri, 15 Sep 2023 04:28:41 +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 B0AC0986659 for ; Fri, 15 Sep 2023 04:28:41 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-IronPort-AV: E=McAfee;i="6600,9927,10833"; a="369470075" X-IronPort-AV: E=Sophos;i="6.02,148,1688454000"; d="scan'208";a="369470075" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10833"; a="694581029" X-IronPort-AV: E=Sophos;i="6.02,148,1688454000"; d="scan'208";a="694581029" Message-ID: <559c0875-24b8-0709-712e-24ffe7830022@intel.com> Date: Fri, 15 Sep 2023 12:28:36 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.15.1 Content-Language: en-US To: virtio-dev@lists.oasis-open.org References: <20230906081637.32185-1-lingshan.zhu@intel.com> <20230914070911-mutt-send-email-mst@kernel.org> From: "Zhu, Lingshan" In-Reply-To: <20230914070911-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [virtio-dev] Re: [PATCH 0/5] virtio: introduce SUSPEND bit and vq state On 9/14/2023 7:14 PM, Michael S. Tsirkin wrote: > On Wed, Sep 06, 2023 at 04:16:32PM +0800, Zhu Lingshan wrote: >> This series introduces >> 1)a new SUSPEND bit in the device status >> Which is used to suspend the device, so that the device states >> and virtqueue states are stabilized. >> >> 2)virtqueue state and its accessor, to get and set last_avail_idx >> and last_used_idx of virtqueues. >> >> The main usecase of these new facilities is Live Migration. >> >> Future work: dirty page tracking and in-flight descriptors. >> This series addresses many comments from Jason, Stefan and Eugenio >> from RFC series. > Compared to Parav's patchset this is much less functional. we will add dirty page tracking and in-flight IO tracker in V2, then it will be a full featured LM solution. They are not in this series because we want this series to be small and focus. > > Assuming that one goes in, can't we add ability to submit > admin commands through MMIO on the device itself and be done with it? I am not sure, IMHO, if we use admin vq as back-ends for MMIO based live migration, then the issues in admin vq still exist, for example: 1)nested virtualization 2)bare-metal live migration 3)QOS 4)introduce more attacking surfaces. And what's more, if we wants to implementing a new capability onbehalf of admin vq, does the capability need to store at least one descriptor buffer, that is the capability length should be at least the max_lengh_of_buffer? If that is not possible, do we need to implement extra fields like length and remaining_length, then the device repeating update the cap data, and the driver repeat reading, way to complex and introduce significant downtime. > >> Zhu Lingshan (5): >> virtio: introduce vq state as basic facility >> virtio: introduce SUSPEND bit in device status >> virtqueue: constraints for virtqueue state >> virtqueue: ignore resetting vqs when SUSPEND >> virtio-pci: implement VIRTIO_F_QUEUE_STATE >> >> content.tex | 118 ++++++++++++++++++++++++++++++++++++++++++++++ >> transport-pci.tex | 18 +++++++ >> 2 files changed, 136 insertions(+) >> >> -- >> 2.35.3 > > --------------------------------------------------------------------- > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org > --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org