[virtio-dev] [PATCH 3/4] content: Introduce driver/device auxiliary notifications for MMIO

[Usama Arif <usama.arif@bytedance.com>]

This includes the additions to the corresponding device and driver
conformances.

Signed-off-by: Usama Arif <usama.arif@bytedance.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Nikos Dragazis <ndragazis@arrikto.com>
---
 content.tex | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/content.tex b/content.tex
index 5430324..0fc50c4 100644
--- a/content.tex
+++ b/content.tex
@@ -2002,6 +2002,9 @@ \subsection{MMIO Device Register Layout}\label{sec:Virtio Transport Options / Vi
         in at least one of the active virtual queues.
       \item [Configuration Change Notification] - bit 1 - the interrupt was
         asserted because the configuration of the device has changed.
+      \item [Device-specific Driver Auxiliary Notification] - bit 2 - the interrupt was
+        asserted because a device-specific event occurred to notify the driver. See
+        \ref{sec:Basic Facilities of a Virtio Device / Notifications}.
     \end{description}
   }
   \hline 
@@ -2074,6 +2077,16 @@ \subsection{MMIO Device Register Layout}\label{sec:Virtio Transport Options / Vi
     apply to the queue selected by writing to \field{QueueSel}.
   }
   \hline
+  \mmioreg{DeviceAuxiliaryNotification}{Device Auxiliary Notifier}{0xd0}{W}{
+    Writing a value to this register triggers a
+    notification to the device. The value written to this register is
+    interpreted as a device auxiliary notification index. The mapping of device auxiliary notifications to
+    device auxiliary notification indices is device-specific. One possible mapping would be
+    to use the integers 0 to N-1 as the device auxiliary notification indices for a total of
+    N device auxiliary notifications. The total number of device auxiliary notifications exposed by the device is
+    also device-specific.
+  }
+  \hline
   \mmioreg{ConfigGeneration}{Configuration atomicity value}{0x0fc}{R}{
     Reading from this register returns a value describing a version of the device-specific configuration space (see \field{Config}).
     The driver can then access the configuration space and, when finished, read \field{ConfigGeneration} again.
@@ -2109,6 +2122,9 @@ \subsection{MMIO Device Register Layout}\label{sec:Virtio Transport Options / Vi
 
 The device MUST NOT access virtual queue contents when \field{QueueReady} is zero (0x0).
 
+The device MUST ignore device auxiliary notifications for invalid device auxiliary notification
+indices.
+
 If VIRTIO_F_RING_RESET has been negotiated, the device MUST present a 0 in
 \field{QueueReady} after the driver has reset the virtqueue via
 \field{QueueReset}.
@@ -2191,6 +2207,8 @@ \subsubsection{Device Initialization}\label{sec:Virtio Transport Options / Virti
 Drivers not expecting shared memory MUST NOT use the shared
 memory registers.
 
+Drivers not expecting device auxiliary notifications MUST NOT use the device auxiliary notification register.
+
 Further initialization MUST follow the procedure described in
 \ref{sec:General Initialization And Device Operation / Device Initialization}~\nameref{sec:General Initialization And Device Operation / Device Initialization}.
 
@@ -2244,8 +2262,9 @@ \subsubsection{Notifications From The Device}\label{sec:Virtio Transport Options
 The memory mapped virtio device is using a single, dedicated
 interrupt signal, which is asserted when at least one of the
 bits described in the description of \field{InterruptStatus}
-is set. This is how the device sends a used buffer notification
-or a configuration change notification to the device.
+is set. This is how the device sends a
+used buffer/configuration change/device-specific notification to the
+device.
 
 \drivernormative{\paragraph}{Notifications From The Device}{Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation / Notifications From The Device}
 After receiving an interrupt, the driver MUST read
-- 
2.25.1


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