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.
+\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.
Still can suspend then collect the idx for 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?
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
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