[virtio-dev] [PATCH v13 07/10] ccw: document ADMIN_VQ as reserved

Michael S. Tsirkin
2023-05-05T15:42:12Z

Adding relevant registers needs more work and it's not
clear what the use-case will be as currently only
the PCI transport is supported. But let's keep the
door open on this.
We already say it's reserved in a central place, but it
does not hurt to remind implementers to mask it.

Note: there are more features to add to this list.
Will be done later with a patch on top.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Parav Pandit <parav@nvidia.com>
Reviewed-by: Zhu Lingshan <lingshan.zhu@intel.com>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>

since v12:
drop "at this time" comment by parav
---
transport-ccw.tex | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/transport-ccw.tex b/transport-ccw.tex
index c492cb9..d42ec7f 100644
--- a/transport-ccw.tex
+++ b/transport-ccw.tex
@@ -599,3 +599,15 @@ \subsubsection{Resetting Devices}\label{sec:Virtio Transport Options / Virtio ov
successful conclusion of the CCW_CMD_VDEV_RESET channel command, although it
MAY also choose to verify reset completion by reading \field{device status} via
CCW_CMD_READ_STATUS and checking whether it is 0 afterwards.
+
+\subsection{Features reserved for future use}\label{sec:Virtio Transport Options / Virtio over channel I/O / Features reserved for future use}
+
+Devices and drivers utilizing Virtio over channel I/O
+do not support the following features:
+\begin{itemize}
+
+\item VIRTIO_F_ADMIN_VQ
+
+\end{itemize}
+
+These features are reserved for future use.