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 EDC62C04A6A for ; Wed, 16 Aug 2023 05:07:14 +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 613E63451 for ; Wed, 16 Aug 2023 05:07:14 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 5913A98643D for ; Wed, 16 Aug 2023 05:07:14 +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 4A39D983EB2; Wed, 16 Aug 2023 05:07:14 +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 37C979863D1; Wed, 16 Aug 2023 05:07:12 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-IronPort-AV: E=McAfee;i="6600,9927,10803"; a="372440774" X-IronPort-AV: E=Sophos;i="6.01,175,1684825200"; d="scan'208";a="372440774" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10803"; a="824101183" X-IronPort-AV: E=Sophos;i="6.01,175,1684825200"; d="scan'208";a="824101183" Message-ID: Date: Wed, 16 Aug 2023 13:07:02 +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> <20230814192904.30062-5-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: Re: [virtio-dev] Re: [RFC PATCH 4/5] virtqueue: constraints for virtqueue state On 8/16/2023 10:11 AM, Jason Wang wrote: > On Tue, Aug 15, 2023 at 7:30 PM Zhu, Lingshan wrote: >> >> >> 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 > replied in another thread. > >>>> + >>>> +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 > This needs to be clarified. OK, I will clarify this in the resting queue section. This reminds me I should add: When SUSPEND is set, the \field{device status} is still operational for both the device and the driver. Because after SUSPEND, the driver may set DRIVER_OK and the device may set NEEDS_RESET. Thanks > > Thanks > > > --------------------------------------------------------------------- > 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