[RFC PATCH 5/5] virtio-pci: implement VIRTIO_F_QUEUE_STATE

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

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

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
 transport-pci.tex | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/transport-pci.tex b/transport-pci.tex
index a5c6719..d9bccb0 100644
--- a/transport-pci.tex
+++ b/transport-pci.tex
@@ -321,6 +321,8 @@ \subsubsection{Common configuration structure layout}\label{sec:Virtio Transport
         le64 queue_device;              /* read-write */
         le16 queue_notif_config_data;   /* read-only for driver */
         le16 queue_reset;               /* read-write */
+        le16 queue_avail_state;         /* read-write */
+        le16 queue_used_state;          /* read-write */
 
         /* About the administration virtqueue. */
         le16 admin_queue_index;         /* read-only for driver */
@@ -415,6 +417,16 @@ \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{queue_avail_state}]
+        This field is vaild 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 vaild 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}).
+
 \item[\field{admin_queue_index}]
         The device uses this to report the index of the first administration virtqueue.
         This field is valid only if VIRTIO_F_ADMIN_VQ has been negotiated.
@@ -488,6 +500,9 @@ \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 against \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