Re: [virtio-comment] [PATCH v3] clarify device reset

[Jason Wang <jasowang@redhat.com>]

On 2021/1/25 äå7:08, Cornelia Huck wrote:
> Properly specify that the method for the driver to request a
> device reset is transport specific, and some action the device
> has to take.
>
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
>
> RFC v2 -> v3:
>    - re-worded the "must not send notifications" clause to avoid guessing
>    - added a driver conformance clause on how a driver should find out
>      when reset is complete
> RFC -> RFC v2:
>    - moved reset spec to basic facilities
>
> ---
>   conformance.tex |  2 ++
>   content.tex     | 19 +++++++++++++++++++
>   2 files changed, 21 insertions(+)
>
> diff --git a/conformance.tex b/conformance.tex
> index eb3324053080..21fe89ccd937 100644
> --- a/conformance.tex
> +++ b/conformance.tex
> @@ -60,6 +60,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
>   \begin{itemize}
>   \item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Status Field}
>   \item \ref{drivernormative:Basic Facilities of a Virtio Device / Feature Bits}
> +\item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Reset}
>   \item \ref{drivernormative:Basic Facilities of a Virtio Device / Device Configuration Space}
>   \item \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues}
>   \item \ref{drivernormative:Basic Facilities of a Virtio Device / Message Framing}
> @@ -271,6 +272,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
>   \begin{itemize}
>   \item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Status Field}
>   \item \ref{devicenormative:Basic Facilities of a Virtio Device / Feature Bits}
> +\item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Reset}
>   \item \ref{devicenormative:Basic Facilities of a Virtio Device / Device Configuration Space}
>   \item \ref{devicenormative:Basic Facilities of a Virtio Device / Message Framing}
>   \item \ref{devicenormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table}
> diff --git a/content.tex b/content.tex
> index 620c0e28c9a7..9cdefe16509e 100644
> --- a/content.tex
> +++ b/content.tex
> @@ -193,6 +193,25 @@ \section{Notifications}\label{sec:Basic Facilities of a Virtio Device
>   terminology. Occasionally, the term event is used to refer to
>   a notification or a receipt of a notification.
>   
> +\section{Device Reset}\label{sec:Basic Facilities of a Virtio Device / Device Reset}
> +
> +The driver may initiate a device reset at various times; notably, during
> +device initialization and device cleanup.
> +
> +The mechanism used by the driver to initiate the reset is transport specific.
> +
> +\devicenormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
> +
> +A device MUST reinitialize device status to 0 after receiving a reset.
> +


We had similar description in "2.1.2 Device Requirements: Device Status 
Field":

"The device MUST initialize device status to 0 upon reset."

Consider we had a dedicated part for reset, maybe we can remove that one.

Thanks


> +A device MUST NOT send notifications after indicating completion of
> +the reset by reinitializing the device status to 0.
> +
> +\drivernormative{\subsection}{Device Reset}{Basic Facilities of a Virtio Device / Device Reset}
> +
> +The driver SHOULD consider a driver-initiated reset complete when it
> +reads the device status as 0.
> +
>   \section{Device Configuration Space}\label{sec:Basic Facilities of a Virtio Device / Device Configuration Space}
>   
>   Device configuration space is generally used for rarely-changing or