[PATCH RFC v7 4/8] Add admin_queue_index register to PCI common configuration structure

["Michael S. Tsirkin" <mst@redhat.com>]

From: Max Gurtovoy <mgurtovoy@nvidia.com>

This new register will be used for querying the index of the admin
virtqueue of a virtio device. To configure, reset or enable the admin
virtqueue, the driver should follow existing queue configuration/setup
sequence.

Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 content.tex | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/content.tex b/content.tex
index 6ce1c07..297cb4a 100644
--- a/content.tex
+++ b/content.tex
@@ -904,6 +904,9 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport
         le64 queue_device;              /* read-write */
         le16 queue_notify_data;         /* read-only for driver */
         le16 queue_reset;               /* read-write */
+
+        /* About the administration virtqueue. */
+        le16 admin_queue_index;         /* read-only for driver */
 };
 \end{lstlisting}
 
@@ -989,6 +992,10 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport
         This field exists only if VIRTIO_F_RING_RESET has been
         negotiated. (see \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}).
 
+\item[\field{admin_queue_index}]
+        The device uses this to report the index of the administration virtqueue.
+        This field is valid only if VIRTIO_F_ADMIN_VQ has been negotiated.
+
 \end{description}
 
 \devicenormative{\paragraph}{Common configuration structure layout}{Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Common configuration structure layout}
@@ -1075,6 +1082,9 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport
 were used before the queue reset.
 (see \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}).
 
+If VIRTIO_F_ADMIN_VQ has been negotiated, the driver MUST
+configure the administration virtqueue using the value of \field{admin_queue_index}.
+
 \subsubsection{Notification structure layout}\label{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Notification capability}
 
 The notification location is found using the VIRTIO_PCI_CAP_NOTIFY_CFG
@@ -6947,6 +6957,10 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
   See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}.
 
   \item[VIRTIO_F_ADMIN_VQ (41)] This feature indicates that an administration virtqueue is supported.
+  At the moment this feature is only supported for devices using
+  \ref{sec:Virtio Transport Options / Virtio Over PCI
+	  Bus}~\nameref{sec:Virtio Transport Options / Virtio Over PCI Bus}
+	  as the transport.
 
 \end{description}
 
-- 
MST