Re: [virtio-comment] [PATCH RFC v2] clarify device reset

[Halil Pasic <pasic@linux.ibm.com>]

On Mon, 18 Jan 2021 17:48:42 +0100
Cornelia Huck <cohuck@redhat.com> wrote:

> On Mon, 18 Jan 2021 16:41:32 +0000
> "Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:
> 
> > * Cornelia Huck (cohuck@redhat.com) 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 -> RFC v2:
> > >   - moved reset spec to basic facilities
> > > 
> > > ---
> > >  conformance.tex |  1 +
> > >  content.tex     | 13 +++++++++++++
> > >  2 files changed, 14 insertions(+)
> > > 
> > > diff --git a/conformance.tex b/conformance.tex
> > > index eb3324053080..3be499ae3c5e 100644
> > > --- a/conformance.tex
> > > +++ b/conformance.tex
> > > @@ -271,6 +271,7 @@ \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..782ddf3ed78d 100644
> > > --- a/content.tex
> > > +++ b/content.tex
> > > @@ -193,6 +193,19 @@ \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.
> > > +
> > > +A device MUST NOT send notifications after receiving a reset.
> > > +    
> > 
> > This feels like a bit of a race in the description;  a Device may have
> > just sent a notification at the point that it receives a reset.
> > When a driver initiates a reset, how does the driver know that the
> > device has received it?  
> 
> I'm actually not 100% sure about that requirement... we can also drop
> it.
> 

Please see my response to Dave's mail. In short, I don't we need to drop
it , I think we need to improve and expand.

Regards,
Halil