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 C7B31C001B0 for ; Tue, 15 Aug 2023 10:50:32 +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 392E442C27 for ; Tue, 15 Aug 2023 10:50:32 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 1E6C89863A7 for ; Tue, 15 Aug 2023 10:50:32 +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 0ACE898633F; Tue, 15 Aug 2023 10:50:32 +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 EB96A98634B; Tue, 15 Aug 2023 10:50:13 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="362403149" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="362403149" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="733799130" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="733799130" Message-ID: <47cc93ea-47e9-6390-4752-02f10f2bdc6e@intel.com> Date: Tue, 15 Aug 2023 18:50:06 +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 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> <20230814192904.30062-2-lingshan.zhu@intel.com> From: "Zhu, Lingshan" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: [virtio-dev] Re: [RFC PATCH 1/5] virtio: introduce SUSPEND bit in device status On 8/15/2023 8:37 AM, Jason Wang wrote: > On Tue, Aug 15, 2023 at 8:26 AM Jason Wang wrote: >> On Mon, Aug 14, 2023 at 7:29 PM Zhu Lingshan wrote: >>> This patch introudces a new status bit in the device status: SUSPEND. >>> >>> This SUSPEND bit can be used by the driver to suspend a device, >>> in order to stablize the device states and virtqueue states. >>> >>> Its main use case is live migration. >> I think patch 3 needs to be squashed into this one. >> >>> Signed-off-by: Jason Wang >>> Signed-off-by: Eugenio PÃrez >>> Signed-off-by: Zhu Lingshan >>> --- >>> content.tex | 18 ++++++++++++++++++ >>> 1 file changed, 18 insertions(+) >>> >>> diff --git a/content.tex b/content.tex >>> index 0a62dce..1bb4401 100644 >>> --- a/content.tex >>> +++ b/content.tex >>> @@ -47,6 +47,9 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev >>> \item[DRIVER_OK (4)] Indicates that the driver is set up and ready to >>> drive the device. >>> >>> +\item[SUSPEND (16)] When VIRTIO_F_SUSPEND is negotiated, indicates that the >>> + device has been suspended by the driver. >>> + >>> \item[DEVICE_NEEDS_RESET (64)] Indicates that the device has experienced >>> an error from which it can't recover. >>> \end{description} >>> @@ -73,6 +76,10 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev >>> recover by issuing a reset. >>> \end{note} >>> >>> +The driver MUST NOT set SUSPEND if FEATURES_OK is not set. >>> + >>> +When set SUSPEND, the driver MUST re-read \field{device status} to ensure the SUSPEND bit is set. >>> + >>> \devicenormative{\subsection}{Device Status Field}{Basic Facilities of a Virtio Device / Device Status Field} >>> >>> The device MUST NOT consume buffers or send any used buffer >>> @@ -82,6 +89,13 @@ \section{\field{Device Status} Field}\label{sec:Basic Facilities of a Virtio Dev >>> that a reset is needed. If DRIVER_OK is set, after it sets DEVICE_NEEDS_RESET, the device >>> MUST send a device configuration change notification to the driver. >>> >>> +The device MUST ignore SUSPEND if FEATURES_OK is not set. >> Is there any value to allow SUSPEND to be set without DRIVER_OK? >> >>> + >>> +The deivce MUST ignore SUSPEND if VIRTIO_F_SUSPEND is not negotiated. >> typo. >> >> Thanks > Btw, it's not clear to me if driver is allowed to clear this bit. To allow terminate a live migration process or resume from a failed live migration, we allow DRIVER_OK to clear SUSPEND, in patch 1. Thanks > > Thanks > >>> + >>> +If VIRTIO_F_SUSPEND is negotiated and SUSPEND is set, the device MUST clear SUSPEND >>> +and resumes operation upon DRIVER_OK. >>> + >>> \section{Feature Bits}\label{sec:Basic Facilities of a Virtio Device / Feature Bits} >>> >>> Each virtio device offers all the features it understands. During >>> @@ -872,6 +886,10 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits} >>> \ref{devicenormative:Basic Facilities of a Virtio Device / Feature Bits} for >>> handling features reserved for future use. >>> >>> + \item[VIRTIO_F_SUSPEND(41)] This feature indicates that the driver can >>> + SUSPEND the device. >>> + See \ref{sec:Basic Facilities of a Virtio Device / Device Status Field}. >>> + >>> \end{description} >>> >>> \drivernormative{\section}{Reserved Feature Bits}{Reserved Feature Bits} >>> -- >>> 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