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 1A30DC04A6A for ; Tue, 15 Aug 2023 10:14:41 +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 6D1C8C624F for ; Tue, 15 Aug 2023 10:14:40 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 69EF598638E for ; Tue, 15 Aug 2023 10:14:40 +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 5D19A98634B; Tue, 15 Aug 2023 10:14:40 +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 4ADB098633F; Tue, 15 Aug 2023 10:14:38 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="403227891" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="403227891" X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.01,202,1684825200"; d="scan'208";a="877299752" Message-ID: Date: Tue, 15 Aug 2023 18:14:31 +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/102.14.0 Content-Language: en-US To: Jason Wang , Stefan Hajnoczi Cc: mst@redhat.com, eperezma@redhat.com, cohuck@redhat.com, virtio-comment@lists.oasis-open.org, virtio-dev@lists.oasis-open.org References: <20230814192904.30062-1-lingshan.zhu@intel.com> <20230814154717.GI3146793@fedora> From: "Zhu, Lingshan" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: [virtio-dev] Re: [virtio-comment] [RFC PATCH 0/5] virtio: introduce SUSPEND bit and vq state On 8/15/2023 9:38 AM, Jason Wang wrote: > On Tue, Aug 15, 2023 at 12:28 AM Stefan Hajnoczi wrote: >> On Tue, Aug 15, 2023 at 03:28:59AM +0800, Zhu Lingshan wrote: >>> This seires 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 stablized. >>> >>> 2)virtqueue state and accessors, to get and set last_avail_idx >>> and last_used_idx of virtqueues. >>> >>> The main usecase of these new facilities is Live Migration. >>> >>> Furture work: dirty page tracking and in-flight descriptors. >>> >>> This is RFC, this series carries on Jason and Eugenio's pervious work. >>> >>> Any comments are welcome. >> In order to support stateful devices like virtiofs, virtio-gpu, or >> virtio-crypto it would be necessary to add device state save/load >> functionality too. > +1 and before save/load, we need to define those states first. > > E.g there are patches that try to fix the GPU suspend/hibernation > which probably requires those facilities as well. I agree, we should define the states of the device types first, like virtio-fs. For virtio-net, one of the states if in-flight descriptors, and this is planned work. > >> Even virtio-net needs device state save/load functionality if the VMM is >> not intercepting the stateful controlq. > Yes, this could be done via trap and emulation. I agree > >> In-flight descriptors can be included in the device state. >> > Probably. Yes, in-flight descriptors and dirty page tracking are in the plan. This series only implements SUSPEND and vq state accessors as the first RFC try to collect comments. > >> In fact, the only reason why I think VIRTIO_F_QUEUE_STATE makes sense is >> for easy integration into existing vhost software stacks. Otherwise we >> should just define a device state save/load interface along with >> standard device state serialization for devices where migration >> interoperability is possible. VIRTIO_F_QUEUE_STATE is a small subset of >> device state save/load. > For simple devices like virtio-net, queue state should be sufficient > for hardware. > >> I think the convenience of integrating into existing vhost software >> stacks is worth the duplication, but I wanted to mention that this >> interface will not be enough to live migrate all device types and we'll >> need something more in the future. > Yes, the patch is a start for simple stateless devices. Yes! Thanks! > > Thanks > >> Stefan >> >>> Zhu Lingshan (5): >>> virtio: introduce SUSPEND bit in device status >>> virtio: introduce vq state as basic facility >>> virtio: The actions by the device upon SUSPEND >>> virtqueue: constraints for virtqueue state >>> virtio-pci: implement VIRTIO_F_QUEUE_STATE >>> >>> content.tex | 120 ++++++++++++++++++++++++++++++++++++++++++++++ >>> transport-pci.tex | 15 ++++++ >>> 2 files changed, 135 insertions(+) >>> >>> -- >>> 2.35.3 >>> >>> >>> 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. >>> >>> Subscribe: virtio-comment-subscribe@lists.oasis-open.org >>> Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org >>> List help: virtio-comment-help@lists.oasis-open.org >>> List archive: https://lists.oasis-open.org/archives/virtio-comment/ >>> Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf >>> List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists >>> Committee: https://www.oasis-open.org/committees/virtio/ >>> Join OASIS: https://www.oasis-open.org/join/ >>> --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org