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 3835AC27C7A for ; Thu, 17 Aug 2023 08:43:05 +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 8A2A145B2D for ; Thu, 17 Aug 2023 08:43:04 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 79672986445 for ; Thu, 17 Aug 2023 08:43:04 +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 6749E9863FE; Thu, 17 Aug 2023 08:43:04 +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 550559863F0; Thu, 17 Aug 2023 08:43:00 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-IronPort-AV: E=McAfee;i="6600,9927,10803"; a="371650273" X-IronPort-AV: E=Sophos;i="6.01,179,1684825200"; d="scan'208";a="371650273" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10803"; a="908322010" X-IronPort-AV: E=Sophos;i="6.01,179,1684825200"; d="scan'208";a="908322010" Message-ID: Date: Thu, 17 Aug 2023 16:42:51 +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: "Uminski, Piotr" , 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> <20230814192904.30062-5-lingshan.zhu@intel.com> <8ce92e00-39f9-3e99-96e2-5599588869e3@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: [virtio-comment] Re: [RFC PATCH 4/5] virtqueue: constraints for virtqueue state On 8/17/2023 4:31 PM, Uminski, Piotr wrote: > >> -----Original Message----- >> From: virtio-comment@lists.oasis-open.org > open.org> On Behalf Of Zhu, Lingshan >> Sent: Tuesday, August 15, 2023 1:30 PM >> 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 >> Subject: [virtio-comment] Re: [RFC PATCH 4/5] virtqueue: constraints for >> virtqueue state >> >> >> >> On 8/15/2023 8:34 AM, Jason Wang wrote: >>> On Mon, Aug 14, 2023 at 7:29 PM Zhu Lingshan >> wrote: >>>> This commit specifies the constraints of the virtqueue state, >>>> and the actions should be taken by the device when SUSPEND >>>> and DRIVER_OK is set >>>> >>>> Signed-off-by: Jason Wang >>>> Signed-off-by: Zhu Lingshan >>>> --- >>>> content.tex | 31 +++++++++++++++++++++++++++++++ >>>> 1 file changed, 31 insertions(+) >>>> >>>> diff --git a/content.tex b/content.tex >>>> index 43bd5de..f6ac581 100644 >>>> --- a/content.tex >>>> +++ b/content.tex >>>> @@ -587,6 +587,37 @@ \subsection{\field{Used State} Field} >>>> >>>> See also \ref{sec:Packed Virtqueues / Driver and Device Ring Wrap >> Counters}. >>>> +\drivernormative{\subsection}{Virtqueue State}{Basic Facilities of a Virtio >> Device / Virtqueue State} >>>> + >>>> +If VIRTIO_F_QUEUE_STATE has been negotiated, the driver MUST set >> SUSPEND in \field{device status} >>>> +first before getting or setting Virtqueue State of any virtqueues. >>> I don't get why this is a must. It could be useful for debugging. >> To avoid race conditions with the device and make the device >> implementation easier > It should be possible to set Virtqueue State in two states: > - Before DRIVER_OK - as a part of the queue creation at target system > - After SUSPEND - when the device was activated and then suspended > Setting state on active device can produce random results and should be forbidden. > We may allow to get Virtqueue State on active device, without SUSPEND. However, we should not mandate the device > to report correct value - on some implementations it may be impossible without suspend. I agree >>>> + >>>> +If VIRTIO_F_QUEUE_STATE has been negotiaged but >> VIRTIO_RING_F_PACKED not been negotiated, >>> typo >> yes >>>> +the driver MUST NOT access \field{Used State} of any virtqueues, it should >> use the >>>> +used index in the used ring. >>>> + >>>> +\devicenormative{\subsection}{Virtqueue State}{Basic Facilities of a Virtio >> Device / Virtqueue State} >>>> + >>>> +If VIRTIO_F_QUEUE_STATE has been negotiated but SUSPEND is not set in >> \field{device status}, >>>> +the device MUST ignore any accesses against Virtqueue State of any >> virtqueues. >>> Btw, do we need to clarify the behavior of ring reset after suspending? >> I think once suspended, the device should ignore resetting a queue >>>> + >>>> +When VIRTIO_F_QUEUE_STATE has been negotiated but >> VIRTIO_RING_F_PACKED is not, >>>> +the device MUST ignore any accesses against \field{Used State}. >>>> + >>>> +If VIRTIO_F_QUEUE_STATE has been negotiaged, the device MUST reset >>>> +the Virtqueue State of every virtqueue upon a reset. >>> Need to define the meaning of "reset" this is important for packed virtqueue. >> I will remove this as Stefan suggested. >>>> + >>>> +If VIRTIO_F_QUEUE_STATE and VIRTIO_RING_F_PACKED have been >> negotiaged, when SUSPEND is set, >>>> +the device MUST record the Virtqueue State of every enabled virtqueue >>>> +in \field{Available State} and \field{Used State} respectively, >>>> +and correspondingly restore the Virtqueue State of every enabled virtqueue >>>> +from \field{Avaiable State} and \field{Used State} when DRIVER_OK is set. >>> We can just let the device report those states in any case then we >>> don't need to care about those details, or did you see any blockers? >> Agree, I will add the definition of used_state of splitted vq in the >> next version >> >> Thanks >>> Thanks >>> >>>> + >>>> +If VIRTIO_F_QUEUE_STATE has been negotiated but >> VIRTIO_RING_F_PACKED has been not, when SUSPEND is set, >>>> +the device MUST record the available state of every enabled virtqueue in >> \field{Available State}, >>>> +and restore the available state of every enabled virtqueue from >> \field{Avaiable State} >>>> +when DRIVER_OK is set. >>>> + >>>> \input{admin.tex} >>>> >>>> \chapter{General Initialization And Device Operation}\label{sec:General >> Initialization And Device Operation} >>>> -- >>>> 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