virtio-msg: tighten initialization and feature negotiation flow

Keep GET_DEVICE_INFO as the only early-discovery transport message,
separate transport feature bits from per-device feature negotiation,
and align the rest of initialization with the core virtio reset,
status, feature negotiation, FEATURES_OK, and DRIVER_OK flow.

Also require GET_DEVICE_INFO to cover all offered feature bits and to
bound max_virtqueues, and define SET_DRIVER_FEATURES as addressed-block
updates that may be accumulated across multiple requests before
FEATURES_OK.

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

Author: bertrand-marquis

conformance.tex

@@ -288,7 +288,7 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Revisions / Device Limits}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Versioning and Forward Compatibility / Device}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Configuration Semantics Profiles / Device}
-\item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Feature Blocks / Device}
+\item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Basic Concepts / Device Feature Blocks / Device}
 \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}
@@ -304,8 +304,6 @@ \section{Conformance Targets}\label{sec:Conformance / Conformance Targets}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Device Operation / Reset / Device}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Transport Messages / Mandatory / Device}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Transport Messages / VIRTIO_MSG_GET_DEVICE_INFO / Device}
-\item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Transport Messages / VIRTIO_MSG_GET_DEVICE_FEATURES / Device}
-\item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Transport Messages / VIRTIO_MSG_SET_DRIVER_FEATURES / Device}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Transport Messages / VIRTIO_MSG_GET_CONFIG / Device}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Transport Messages / VIRTIO_MSG_SET_CONFIG / Device}
 \item \ref{devicenormative:Virtio Transport Options / Virtio Over Messages / Transport Messages / VIRTIO_MSG_GET_DEVICE_STATUS / Device}