The virtio documentation currently doesn't define any generic
requirements that are applicable to all transports. These may be useful
while adding support for a new transport.
This commit tries to define the same.
Signed-off-by: Viresh Kumar <viresh.kumar(a)linaro.org>
---
Alex,
Sending it to Stratos list first to get some initial feedback.
content.tex | 48 ++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 46 insertions(+), 2 deletions(-)
diff --git a/content.tex b/content.tex
index 0a62dce5f65f..489028b6ef3f 100644
--- a/content.tex
+++ b/content.tex
@@ -631,8 +631,52 @@ \section{Device Cleanup}\label{sec:General Initialization And Device Operation /
\chapter{Virtio Transport Options}\label{sec:Virtio Transport Options}
-Virtio can use various different buses, thus the standard is split
-into virtio general and bus-specific sections.
+The virtio devices are exposed to the guest as if they are physical
+devices using a specific transport method, like PCI, MMIO or Channel
+I/O. The transport methods define various aspects of communication
+between the device and the driver, like device discovery, exchanging
+capabilities, interrupt handling, and data transfer. Virtio can use
+various different buses, thus the standard is split into virtio general
+and bus-specific sections.
+
+\section{Virtio Transport Requirements}\label{sec:Virtio Transport Options / Virtio Transport Requirements}
+
+\devicenormative{\subsection}{Virtio Transport Requirements}{Virtio Transport Options}
+
+The device MUST present each event, in a transport defined way, from the
+moment it takes place until the driver acknowledges the interrupt, in a
+transport defined way.
+
+The device MUST NOT access virtqueue contents before the driver notifies
+that the queue is ready for access, in a transport defined way.
+
+The device MUST NOT access buffers previously modified on the queue by
+it, after it has notified the driver about their availability.
+
+The device MUST reset the virtqueues if asked by the driver, in a
+transport defined way.
+
+\drivernormative{\subsection}{Virtio Transport Requirements}{Virtio Transport Options}
+
+The driver MUST NOT access memory locations outside what's presented by
+the device.
+
+The driver MUST NOT write to the read-only registers and MUST NOT read
+from the write-only registers.
+
+The driver MUST acknowledge events presented by the device, as mandated
+by the transport.
+
+The driver MUST NOT access virtqueue contents before the device notifies
+that the queue is ready for access, in a transport defined way.
+
+The driver MUST NOT access buffers previously added to the queue by the
+driver, after it has notified the device about their availability. The
+driver MAY access the same after the device has processed them and
+notified the same to the driver, in a transport defined way.
+
+The driver MAY ask the device to reset the virtqueues, in a transport
+defined way.
\input{transport-pci.tex}
\input{transport-mmio.tex}
--
2.31.1.272.g89b43f80a514
