[RFC PATCH 4/5] virtqueue: constraints for virtqueue state

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

This commit specifies the constraints of the virtqueue state,
and the actions should be taken by the device when SUSPEND
and DRIVER_OK is set

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
 content.tex | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/content.tex b/content.tex
index 43bd5de..f6ac581 100644
--- a/content.tex
+++ b/content.tex
@@ -587,6 +587,37 @@ \subsection{\field{Used State} Field}
 
 See also \ref{sec:Packed Virtqueues / Driver and Device Ring Wrap Counters}.
 
+\drivernormative{\subsection}{Virtqueue State}{Basic Facilities of a Virtio Device / Virtqueue State}
+
+If VIRTIO_F_QUEUE_STATE has been negotiated, the driver MUST set SUSPEND in \field{device status}
+first before getting or setting Virtqueue State of any virtqueues.
+
+If VIRTIO_F_QUEUE_STATE has been negotiaged but VIRTIO_RING_F_PACKED not been negotiated,
+the driver MUST NOT access \field{Used State} of any virtqueues, it should use the
+used index in the used ring.
+
+\devicenormative{\subsection}{Virtqueue State}{Basic Facilities of a Virtio Device / Virtqueue State}
+
+If VIRTIO_F_QUEUE_STATE has been negotiated but SUSPEND is not set in \field{device status},
+the device MUST ignore any accesses against Virtqueue State of any virtqueues.
+
+When VIRTIO_F_QUEUE_STATE has been negotiated but VIRTIO_RING_F_PACKED is not,
+the device MUST ignore any accesses against \field{Used State}.
+
+If VIRTIO_F_QUEUE_STATE has been negotiaged, the device MUST reset
+the Virtqueue State of every virtqueue upon a reset.
+
+If VIRTIO_F_QUEUE_STATE and VIRTIO_RING_F_PACKED have been negotiaged, when SUSPEND is set,
+the device MUST record the Virtqueue State of every enabled virtqueue
+in \field{Available State} and \field{Used State} respectively,
+and correspondingly restore the Virtqueue State of every enabled virtqueue
+from \field{Avaiable State} and \field{Used State} when DRIVER_OK is set.
+
+If VIRTIO_F_QUEUE_STATE has been negotiated but VIRTIO_RING_F_PACKED has been not, when SUSPEND is set,
+the device MUST record the available state of every enabled virtqueue in \field{Available State},
+and restore the available state of every enabled virtqueue from \field{Avaiable State}
+when DRIVER_OK is set.
+
 \input{admin.tex}
 
 \chapter{General Initialization And Device Operation}\label{sec:General Initialization And Device Operation}
-- 
2.35.3