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 8ABBFC001E0 for ; Tue, 15 Aug 2023 11:30:15 +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 D8367613F8 for ; Tue, 15 Aug 2023 11:30:13 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id D3C549863A5 for ; Tue, 15 Aug 2023 11:30:13 +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 C27DE98633F; Tue, 15 Aug 2023 11:30:13 +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 AF71D98634B; Tue, 15 Aug 2023 11:30:12 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="436152294" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="436152294" X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10802"; a="763239755" X-IronPort-AV: E=Sophos;i="6.01,174,1684825200"; d="scan'208";a="763239755" Message-ID: <8ce92e00-39f9-3e99-96e2-5599588869e3@intel.com> Date: Tue, 15 Aug 2023 19:30:06 +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> <20230814192904.30062-5-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 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 > >> + >> +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 >> --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org