virtio-msg: define transport ownership and request completion

Clarify which responsibilities belong to the bus versus the transport
layer, tighten error signaling and completion rules, and define how
common message IDs, tokens, and repeated request fields are used for
request/response association.

State that each valid supported request completes with exactly one
protocol response or a transport-visible failure, and keep the related
driver and device conformance references aligned with that model.

Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>

Author: bertrand-marquis

conformance.tex

@@ -156,6 +156,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
 \item \ref{drivernormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Revisions / Driver Limits}
 \item \ref{drivernormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Versioning and Forward Compatibility / Driver}
 \item \ref{drivernormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Configuration Semantics Profiles / Driver}
+\item \ref{drivernormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Error Signaling / Driver}
 \item \ref{drivernormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Endianness / Driver}
 \item \ref{drivernormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Common Message Format / Driver}
 \item \ref{drivernormative:Virtio Transport Options / Virtio Over Messages / Device Initialization / Overview / Driver}
@@ -290,6 +291,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Error Signaling / Device}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Endianness / Device}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Common Message Format / Device}
+\item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Ordering / Device}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Device Initialization / Device Features / Device}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Device Initialization / Device Configuration / Device}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Device Initialization / Virtqueue Configuration / Device}
@@ -363,8 +365,15 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
 \item \ref{busnormative:Virtio Transport Options / Virtio Over Messages / Transport Messages / Runtime Notifications / Bus}
 \item \ref{busnormative:Virtio Transport Options / Virtio Over Messages / Device Operation / Hotplug and Removal / Bus}
 \item \ref{busnormative:Virtio Transport Options / Virtio Over Messages / Transport Messages / VIRTIO_MSG_EVENT_AVAIL / Bus}
-\item \ref{busnormative:Virtio Transport Options / Virtio Over Messages / Bus Messages / GET_DEVICES / Bus}
-\item \ref{busnormative:Virtio Transport Options / Virtio Over Messages / Bus Messages / PING / Bus}
+\end{itemize}
+
+If a Virtio Over Messages bus implementation supports optional bus messages, it
+MUST also conform to the corresponding normative statements:
+
+\begin{itemize}
+\item \ref{busnormative:Virtio Transport Options / Virtio Over Messages / Bus Messages / GET_DEVICES / Bus} (if BUS_MSG_GET_DEVICES is supported)
+\item \ref{busnormative:Virtio Transport Options / Virtio Over Messages / Bus Messages / PING / Bus} (if BUS_MSG_PING is supported)
+\item \ref{busnormative:Virtio Transport Options / Virtio Over Messages / Bus Messages / EVENT_DEVICE / Bus} (if BUS_MSG_EVENT_DEVICE is supported)
 \end{itemize}
 
 \conformance{\section}{Legacy Interface: Transitional Device and Transitional Driver Conformance}\label{sec:Conformance / Legacy Interface: Transitional Device and Transitional Driver Conformance}