virtio-msg: propose common-spec integration text

Update common-spec text so Virtio Over Messages is referenced
from the core device facilities and introduction.

This is a proposal for changes in the virtio common
specification to properly insert the virtio message transport
in the transport-neutral text.

Keep the change minimal for now:
- update content.tex to mention Virtio Over Messages in the
  transport list and in VIRTIO_F_ADMIN_VQ text
- update introduction.tex to mention message-based transports

We could also adapt newtransport.tex, but that is intentionally
left out here to keep the proposal minimal.

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

Author: bertrand-marquis

content.tex

@@ -2,7 +2,9 @@ \chapter{Basic Facilities of a Virtio Device}\label{sec:Basic Facilities of a Vi
 
 A virtio device is discovered and identified by a bus-specific method
 (see the bus specific sections: \ref{sec:Virtio Transport Options / Virtio Over PCI Bus}~\nameref{sec:Virtio Transport Options / Virtio Over PCI Bus},
-\ref{sec:Virtio Transport Options / Virtio Over MMIO}~\nameref{sec:Virtio Transport Options / Virtio Over MMIO} and \ref{sec:Virtio Transport Options / Virtio Over Channel I/O}~\nameref{sec:Virtio Transport Options / Virtio Over Channel I/O}).  Each
+\ref{sec:Virtio Transport Options / Virtio Over MMIO}~\nameref{sec:Virtio Transport Options / Virtio Over MMIO},
+\ref{sec:Virtio Transport Options / Virtio Over Channel I/O}~\nameref{sec:Virtio Transport Options / Virtio Over Channel I/O}
+and \ref{sec:Virtio Transport Options / Virtio Over Messages}~\nameref{sec:Virtio Transport Options / Virtio Over Messages}). Each
 device consists of the following parts:
 
 \begin{itemize}
@@ -931,11 +933,16 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
 
   \item[VIRTIO_F_ADMIN_VQ(41)] This feature indicates that the device exposes one or more
   administration virtqueues.
-  At the moment this feature is only supported for devices using
-  \ref{sec:Virtio Transport Options / Virtio Over PCI
+  Devices using \ref{sec:Virtio Transport Options / Virtio Over PCI
 	  Bus}~\nameref{sec:Virtio Transport Options / Virtio Over PCI Bus}
-	  as the transport and is reserved for future use for
-	  devices using other transports (see
+	  expose administration virtqueues using the transport-specific
+	  fields defined by that transport. Devices using
+	  \ref{sec:Virtio Transport Options / Virtio Over Messages}~\nameref{sec:Virtio Transport Options / Virtio Over Messages}
+	  expose administration virtqueues through the device information
+	  reported by that transport.
+
+  For devices using other transports, this feature is reserved for
+	  future use (see
 	  \ref{drivernormative:Basic Facilities of a Virtio Device / Feature Bits}
 	and
 	\ref{devicenormative:Basic Facilities of a Virtio Device / Feature Bits} for

introduction.tex

@@ -20,7 +20,7 @@ \chapter{Introduction}
 \item[Standard:] Virtio makes no assumptions about the environment in which
   it operates, beyond supporting the bus to which device is attached.
   In this specification, virtio
-  devices are implemented over MMIO, Channel I/O and PCI bus transports
+  devices are implemented over MMIO, Channel I/O, PCI bus, and message-based transports
 \footnote{The Linux implementation further separates the virtio
 transport code from the specific virtio drivers: these drivers are shared
 between different transports.