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

[Jason Wang <jasowang@redhat.com>]

On 2021/1/27 äå7:11, Cornelia Huck wrote:
> On Wed, 27 Jan 2021 11:07:53 +0800
> Jason Wang <jasowang@redhat.com> wrote:
>
> > 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.
> Maybe we can replace the normative statement with an informal
> description in the device status section? I.e. something like
>
> "The device status field starts out as 0, and is reinitialized to 0 by
> the device during reset."


Fine with me.

Thanks


> > 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
>
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