Re: [virtio-dev] [RFC PATCH 4/5] virtqueue: constraints for virtqueue state

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Tue, Aug 15, 2023 at 03:29:03AM +0800, 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 <jasowang@redhat.com>
> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
> ---
>  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.
> +
> +If VIRTIO_F_QUEUE_STATE has been negotiaged but VIRTIO_RING_F_PACKED not been negotiated,

"negotiated"

Please run a spell checker.

> +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.

"accesses against" is not commonly used in English. "accesses to" is more natural.

> +
> +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}.

Same here.

> +
> +If VIRTIO_F_QUEUE_STATE has been negotiaged, the device MUST reset
> +the Virtqueue State of every virtqueue upon a reset.

I'm not sure if this statement is necessary since Virtqueue State
becomes inaccessible when the device is reset. By definition, Virtqueue
State is the device-internal state of the virtqueue, so it follows
logically that next time the driver can access the Virtqueue State after
reset, it contains the current state and not previous state from before
reset.

> +
> +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.

"Available State"

> +
> +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}

"Available 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
> 
> 
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