RE: [PATCH v3 3/3] virtio: introduce SUSPEND and RESUME feature

> From: Cornelia Huck <[email protected]>
> Sent: 26 June 2025 09:13 PM


> On Thu, Jun 26 2025, "Zhu, Lingshan" <[email protected]> wrote:
> 
> > On 6/26/2025 7:59 PM, Parav Pandit wrote:
> >
> >>> From: Zhu Lingshan<[email protected]>
> >>> Sent: 23 June 2025 02:07 PM
> >>> @@ -629,6 +632,54 @@ \section{Device Cleanup}\label{sec:General
> >>> Initialization And Device Operation /
> >>>
> >>>   Thus a driver MUST ensure a virtqueue isn't live (by device reset)
> >>> before removing exposed buffers.
> >>>
> >>> +\section{Device Suspend}\label{sec:General Initialization And
> >>> +Device Operation / Device Suspend}
> >>> +
> >>> +If VIRTIO_F_SUSPEND is negotiated, the driver is eligible to
> >>> +suspend the
> >>> device by setting the SUSPEND bit in \field{device status} to 1, and
> >>> the device SHOULD set the DRIVER_OK bit to 0 once it has been
> suspended.
> >>> +
> >> You ignored the inputs.
> >> I do not agree to add the "SHOULD" normative wording in the general
> description area.
> >> The reasoning is explained already.
> >> Please adapt to the existing style of this spec to keep the normative in
> requirements section.
> >>
> >> If VIRTIO_F_SUSPEND is negotiated, the driver is eligible to suspend
> >> the device by setting the SUSPEND bit in \field{device status} to 1,
> >> and the device sets the DRIVER_OK bit to 0 once it has been suspended.
> >>
> >> Is this really that hard to write above way?
> >
> > I believe you totally ignored my replies in the last thread.
> > There are no rules forbid using "SHOULD" in any non-normative sections.
> > Now here I copy the reply here again:
> >
> > In the spec section 1.3 Terminology, it says:
> >
> > The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”,
> “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “NOT RECOMMENDED”,
> “MAY”, and “OPTIONAL” in this document are to be interpreted as described
> in [RFC2119] and [RFC8174] when, and only when, they appear in all capitals,
> as shown here.
> >
> > RFC 2119 says:
> >
> > SHOULD This word, or the adjective "RECOMMENDED", mean that there
> >     may exist valid reasons in particular circumstances to ignore a
> >     particular item, but the full implications must be understood and
> >     carefully weighed before choosing a different course.
> >
> >
> > Here this "SHOULD" exactly conforms to the definition.
> >
> > "SHOULD" has already been used in non-normative sections, for example:
> > 2.5.4 Legacy Interfaces: when using the legacy interface, drivers SHOULD
> read these fields multiple times until two reads generate a consistent result.
> >
> > The spec does not say: “SHOULD” can only be used in driver or device
> requirements section.
> >
> > @MST, we need your input
> >
> 
> Not MST, but you can have my input.
> 
> We refer to the RFC for the definitions of SHOULD and friends, it does not say
> where to use them.
> 
> The intention is to use them in normative statements only, so that
> implementers have clear guidelines on the requirements. The legacy sections
> are arguably a special case (for implementers who want to support legacy
> implementations.) I don't think we want the all-caps key words leaking into
> other sections (any more than what might have happened already.)

+1.
Let me send a short patch to update our "terminology" section to provide this guidance.
It will be useful in general for everyone.
Sending soon.