This patch allows the driver to reset a queue individually.
This is very common on general network equipment. By disabling a queue,
you can quickly reclaim the buffer currently on the queue. If necessary,
we can reinitialize the queue separately.
For example, when virtio-net implements support for AF_XDP, we need to
disable a queue to release all the original buffers when AF_XDP setup.
And quickly release all the AF_XDP buffers that have been placed in the
queue when AF_XDP exits.
Since mmio's QueueReady allows setting 0 to stop the queue, there is no
need to distinguish whether VIRTIO_F_RING_RESET is negotiated.
Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com>
---
content.tex | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/content.tex b/content.tex
index 7cec1c3..70a9765 100644
--- a/content.tex
+++ b/content.tex
@@ -1001,7 +1001,13 @@ \subsubsection{Common configuration structure
layout}\label{sec:Virtio Transport
After writing 0 to \field{device_status}, the driver MUST wait for a read of
\field{device_status} to return 0 before reinitializing the device.
-The driver MUST NOT write a 0 to \field{queue_enable}.
+If the VIRTIO_F_RING_RESET feature bit is not negotiated,
+the driver MUST NOT write a 0 to \field{queue_enable}.
+
+Otherwise, if the VIRTIO_F_RING_RESET feature bit is negotiated,
+the driver can stop using the queue by writing a 0 to \field{queue_enable} and
+MUST read the value back to ensure synchronization. Then optionally re-enable
+the queue.
\subsubsection{Notification structure layout}\label{sec:Virtio Transport
Options / Virtio Over PCI Bus / PCI Device Layout / Notification capability}
@@ -6672,6 +6678,9 @@ \chapter{Reserved Feature Bits}\label{sec:Reserved
Feature Bits}
transport specific.
For more details about driver notifications over PCI see \ref{sec:Virtio
Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And
Device Operation / Available Buffer Notifications}.
+ \item[VIRTIO_F_RING_RESET(40)] This feature indicates
+ that the driver can reset a queue individually.
+
\end{description}
\drivernormative{\section}{Reserved Feature Bits}{Reserved Feature Bits}
--
2.31.0
---------------------------------------------------------------------
To unsubscribe, e-mail: virtio-dev-unsubscr...@lists.oasis-open.org
For additional commands, e-mail: virtio-dev-h...@lists.oasis-open.org
