On Tue, Aug 15, 2023 at 7:17 PM Zhu, Lingshan <[email protected]> wrote:
>
>
>
> On 8/15/2023 8:29 AM, Jason Wang wrote:
> > On Mon, Aug 14, 2023 at 7:29 PM Zhu Lingshan <[email protected]> wrote:
> >> This commit specifies the actions to be taken by the device upon
> >> SUSPEND.
> >>
> >> Signed-off-by: Jason Wang <[email protected]>
> >> Signed-off-by: Eugenio PÃrez <[email protected]>
> >> Signed-off-by: Zhu Lingshan <[email protected]>
> >> ---
> >> content.tex | 9 +++++++++
> >> 1 file changed, 9 insertions(+)
> >>
> >> diff --git a/content.tex b/content.tex
> >> index 074f43e..43bd5de 100644
> >> --- a/content.tex
> >> +++ b/content.tex
> >> @@ -96,6 +96,15 @@ \section{\field{Device Status} Field}\label{sec:Basic
> >> Facilities of a Virtio Dev
> >> If VIRTIO_F_SUSPEND is negotiated and SUSPEND is set, the device MUST
> >> clear SUSPEND
> >> and resumes operation upon DRIVER_OK.
> >>
> >> +If VIRTIO_F_SUSPEND is negotiated, when SUSPEND is set, the device MUST
> >> perform the following operations:
> >> +\begin{itemize}
> >> +\item Stop comsuming any descriptors
> > Typo.
> yes will fix
> >
> >> +\item Mark all finished descriptors as used and send used buffer
> >> notification to the driver
> > What happens to the unfinished descriptors?
> still in the descriptors table or considered as in-flight, we will post
> a patch tracking in-flight descriptors.
So I think we should either
1) add in-flight descriptors in this series
or
2) force a flush
To make sure the new proposed function is complete.
> >
> >> +\item Record Virtqueue State of each enabled virtqueue, see section
> >> \ref{sec:Virtqueues / Virtqueue State}
> > This basically means those states are only available after suspending
> > or not? It would be still useful for debugging if we allow it without
> > suspending.
> Yes, for now only allow to read/write the virtqueue state after setting
> SUSPEND, this is to avoid race conditions with the device.
For debugging, we don't need to care about those races. A lot of
hardware allow to expose those via e.g ethtool.
>
> Still can suspend then collect the idx for debugging?
I mean for runtime debugging.
> >
> >> +\item Pause its operation and preserve all configurations in its Device
> >> Configuration Space, see \ref{sec:Basic Facilities of a Virtio Device /
> >> Device Configuration Space}
> > We probably need to define the "pause" here (e.g what happens to the
> > inflight descriptors).
> Shall we say: freeze both its data-plane and control-plane?
I mean if we've defined "suspend" we can simply use "suspend" instead
of "pause"?
Thanks
> >
> > Thanks
> >
> >> +\item Present SUSPEND in \field{device status}
> >> +\end{itemize}
> >> +
> >> \section{Feature Bits}\label{sec:Basic Facilities of a Virtio Device /
> >> Feature Bits}
> >>
> >> Each virtio device offers all the features it understands. During
> >> --
> >> 2.35.3
> >>
> >
> > ---------------------------------------------------------------------
> > To unsubscribe, e-mail: [email protected]
> > For additional commands, e-mail: [email protected]
> >
>
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
