[PATCH V2 4/6] virtio-pci: implement VIRTIO_F_QUEUE_STATE

[Zhu Lingshan <lingshan.zhu@intel.com>]

This patch adds two new le16 fields to common configuration structure
to support VIRTIO_F_QUEUE_STATE in PCI transport layer.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
 transport-pci.tex | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/transport-pci.tex b/transport-pci.tex
index a5c6719..3161519 100644
--- a/transport-pci.tex
+++ b/transport-pci.tex
@@ -325,6 +325,10 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport
         /* About the administration virtqueue. */
         le16 admin_queue_index;         /* read-only for driver */
         le16 admin_queue_num;         /* read-only for driver */
+
+	/* Virtqueue state */
+        le16 queue_avail_state;         /* read-write */
+        le16 queue_used_state;          /* read-write */
 };
 \end{lstlisting}
 
@@ -428,6 +432,17 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport
 	The value 0 indicates no supported administration virtqueues.
 	This field is valid only if VIRTIO_F_ADMIN_VQ has been
 	negotiated.
+
+\item[\field{queue_avail_state}]
+        This field is valid only if VIRTIO_F_QUEUE_STATE has been
+        negotiated. The driver sets and gets the available state of
+        the virtqueue here (see \ref{sec:Virtqueues / Virtqueue State}).
+
+\item[\field{queue_used_state}]
+        This field is valid only if VIRTIO_F_QUEUE_STATE has been
+        negotiated. The driver sets and gets the used state of the
+        virtqueue here (see \ref{sec:Virtqueues / Virtqueue State}).
+
 \end{description}
 
 \devicenormative{\paragraph}{Common configuration structure layout}{Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Common configuration structure layout}
@@ -488,6 +503,9 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport
 present either a value of 0 or a power of 2 in
 \field{queue_size}.
 
+If VIRTIO_F_QUEUE_STATE has not been negotiated, the device MUST ignore
+any accesses to \field{queue_avail_state} and \field{queue_used_state}.
+
 If VIRTIO_F_ADMIN_VQ has been negotiated, the value
 \field{admin_queue_index} MUST be equal to, or bigger than
 \field{num_queues}; also, \field{admin_queue_num} MUST be
-- 
2.35.3