[virtio-dev] [PATCH v2 1/5] virtio-mmio: Add feature bit for MMIO notification

[Jing Liu]

All the queues notifications use the same register on MMIO transport
layer. Add a feature bit (39) for enhancing the notification capability.
The detailed mechanism would be in next patch.

Co-developed-by: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
Signed-off-by: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx>
Co-developed-by: Liu Jiang <gerry@xxxxxxxxxxxxxxxxx>
Signed-off-by: Liu Jiang <gerry@xxxxxxxxxxxxxxxxx>
Co-developed-by: Zha Bin <zhabin@xxxxxxxxxxxxxxxxx>
Signed-off-by: Zha Bin <zhabin@xxxxxxxxxxxxxxxxx>
Signed-off-by: Jing Liu <jing2.liu@xxxxxxxxxxxxxxx>
---
 content.tex | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/content.tex b/content.tex
index d68cfaf..826bc7d 100644
--- a/content.tex
+++ b/content.tex
@@ -5810,6 +5810,9 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
   in its device notifications.
   See \ref{sec:Virtqueues / Driver notifications}~\nameref{sec:Virtqueues / Driver notifications}.
 \end{description}
+  \item[VIRTIO_F_MMIO_NOTIFICATION(39)] This feature indicates
+  that the device supports enhanced notification mechanism on
+  MMIO transport layer.
 
 \drivernormative{\section}{Reserved Feature Bits}{Reserved Feature Bits}
 
@@ -5843,6 +5846,8 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
 or partially reset, and even without re-negotiating
 VIRTIO_F_SR_IOV after the reset.
 
+A driver SHOULD accept VIRTIO_F_MMIO_NOTIFICATION if it is offered.
+
 \devicenormative{\section}{Reserved Feature Bits}{Reserved Feature Bits}
 
 A device MUST offer VIRTIO_F_VERSION_1.  A device MAY fail to operate further
@@ -5872,6 +5877,10 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
 and presents a PCI SR-IOV capability structure, otherwise
 it MUST NOT offer VIRTIO_F_SR_IOV.
 
+If VIRTIO_F_MMIO_NOTIFICATION has been negotiated, a device
+MUST support handling the notification from driver at the
+calculated location.
+
 \section{Legacy Interface: Reserved Feature Bits}\label{sec:Reserved Feature Bits / Legacy Interface: Reserved Feature Bits}
 
 Transitional devices MAY offer the following:
-- 
2.7.4