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 498FACE79AB for ; Wed, 20 Sep 2023 07:30:28 +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 ACEB72169E for ; Wed, 20 Sep 2023 07:30:27 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 7AA1C98666C for ; Wed, 20 Sep 2023 07:30:27 +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 60EFD986668; Wed, 20 Sep 2023 07:30:27 +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 50B8E986669; Wed, 20 Sep 2023 07:30:26 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-IronPort-AV: E=McAfee;i="6600,9927,10838"; a="383995581" X-IronPort-AV: E=Sophos;i="6.02,161,1688454000"; d="scan'208";a="383995581" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10838"; a="870266763" X-IronPort-AV: E=Sophos;i="6.02,161,1688454000"; d="scan'208";a="870266763" Message-ID: Date: Wed, 20 Sep 2023 15:30:14 +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: "Chen, Jiqian" , Parav Pandit , "Michael S. Tsirkin" Cc: Gerd Hoffmann , Jason Wang , Xuan Zhuo , David Airlie , Gurchetan Singh , Chia-I Wu , =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= , Robert Beckett , Mikhail Golubev-Ciuchea , "virtio-comment@lists.oasis-open.org" , "virtio-dev@lists.oasis-open.org" , "qemu-devel@nongnu.org" , "linux-kernel@vger.kernel.org" , Stefano Stabellini , =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , "Deucher, Alexander" , "Koenig, Christian" , "Hildebrand, Stewart" , Xenia Ragiadakou , "Huang, Honglei1" , "Zhang, Julia" , "Huang, Ray" References: <20230919114242.2283646-1-Jiqian.Chen@amd.com> <20230919114242.2283646-2-Jiqian.Chen@amd.com> <20230919082802-mutt-send-email-mst@kernel.org> <701bb67c-c52d-4eb3-a6ed-f73bd5d0ff33@intel.com> From: "Zhu, Lingshan" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [virtio-dev] Re: [virtio-comment] Re: [VIRTIO PCI PATCH v5 1/1] transport-pci: Add freeze_mode to virtio_pci_common_cfg On 9/20/2023 3:24 PM, Chen, Jiqian wrote: > Hi Lingshan, > It seems you reply to the wrong email thread. They are not related to my patch. These reply to Parva's comments. @Parva, if you want to discuss more about live migration, please reply in my thread, lets don't flood here. > > On 2023/9/20 15:06, Zhu, Lingshan wrote: >> >> On 9/20/2023 2:58 PM, Parav Pandit wrote: >>>> From: Chen, Jiqian >>>> Sent: Wednesday, September 20, 2023 12:03 PM >>>> If driver write 0 to reset device, can the SUSPEND bit be cleared? >>> It must as reset operation, resets everything else and so the suspend too. >>> >>>> (pci_pm_resume->virtio_pci_restore->virtio_device_restore- >>>>> virtio_reset_device) >>>> If SUSPEND is cleared, then during the reset process in Qemu, I can't judge if >>>> the reset request is from guest restore process or not, and then I can't change >>>> the reset behavior. >>> Reset should not be influenced by suspend. >>> Suspend should do the work of suspend and reset to do the reset. >>> >>> The problem to overcome in [1] is, resume operation needs to be synchronous as it involves large part of context to resume back, and hence just asynchronously setting DRIVER_OK is not enough. >>> The sw must verify back that device has resumed the operation and ready to answer requests. >> this is not live migration, all device status and other information still stay in the device, no need to "resume" context, just resume running. >> >> Like resume from a failed LM. >>> This is slightly different flow than setting the DRIVER_OK for the first time device initialization sequence as it does not involve large restoration. >>> >>> So, to merge two ideas, instead of doing DRIVER_OK to resume, the driver should clear the SUSPEND bit and verify that it is out of SUSPEND. >>> >>> Because driver is still in _OK_ driving the device flipping the SUSPEND bit. >> Please read the spec, it says: >> The driver MUST NOT clear a device status bit >> >> --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org