PCI devices support memory BAR regions for performant driver notifications using the notification capability. Enable transitional MMR devices to use it in simpler manner.
Co-developed-by: Satananda Burla <[email protected]> Signed-off-by: Parav Pandit <[email protected]> --- transport-pci.tex | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/transport-pci.tex b/transport-pci.tex index 55a6aa0..4fd9898 100644 --- a/transport-pci.tex +++ b/transport-pci.tex @@ -763,6 +763,34 @@ \subsubsection{Notification structure layout}\label{sec:Virtio Transport Options cap.length >= queue_notify_off * notify_off_multiplier + 4 \end{lstlisting} +\paragraph{Transitional MMR Interface: A note on Notification Capability} +\label{sec:Virtio Transport Options / Virtio Over PCI Bus / Virtio Structure PCI Capabilities / Notification capability / Transitional MMR Interface} + +The transitional MMR device benefits from receiving driver +notifications at the Queue Notification address offered using +the notification capability, rather than via the memory mapped +legacy QueueNotify configuration register. + +Transitional MMR device uses same Queue Notification address +within a BAR for all virtqueues: +\begin{lstlisting} +cap.offset +\end{lstlisting} + +The transitional MMR device MUST support Queue Notification +address within a BAR for all virtqueues at: +\begin{lstlisting} +cap.offset +\end{lstlisting} + +The transitional MMR driver that wants to use driver +notifications offered using notification capability MUST use +same Queue Notification address within a BAR for all virtqueues at: + +\begin{lstlisting} +cap.offset +\end{lstlisting} + \subsubsection{ISR status capability}\label{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / ISR status capability} The VIRTIO_PCI_CAP_ISR_CFG capability -- 2.26.2 --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
