[PATCH v3 1/2] Documentation/driver-api/vfio-mediated-device.rst: update for aggregation support

[Zhenyu Wang]

Update doc for mdev aggregation support. Describe mdev generic
parameter directory under mdev device directory.

Cc: Kevin Tian <kevin.tian at intel.com>
Cc: "Jiang, Dave" <dave.jiang at intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw at linux.intel.com>
---
 .../driver-api/vfio-mediated-device.rst       | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
index 25eb7d5b834b..fcc031adcf63 100644
--- a/Documentation/driver-api/vfio-mediated-device.rst
+++ b/Documentation/driver-api/vfio-mediated-device.rst
@@ -269,6 +269,9 @@ Directories and Files Under the sysfs for Each mdev Device
   |--- [$MDEV_UUID]
          |--- remove
          |--- mdev_type {link to its type}
+         |--- mdev [optional]
+	     |--- aggregated_instances [optional]
+	     |--- max_aggregation [optional]
          |--- vendor-specific-attributes [optional]
 
 * remove (write only)
@@ -281,6 +284,25 @@ Example::
 
 	# echo 1 > /sys/bus/mdev/devices/$mdev_UUID/remove
 
+* mdev directory (optional)
+
+Vendor driver could create mdev directory to specify extra generic parameters
+on mdev device by its type. Currently aggregation parameters are defined.
+Vendor driver should provide both items to support.
+
+1) aggregated_instances (read/write)
+
+Set target aggregated instances for device. Reading will show current
+count of aggregated instances. Writing value larger than max_aggregation
+would fail and return error. Multiple writes could be done to adjust the
+setting but ensure to not exceed max_aggregation. Normally write won't
+be success after device open.
+
+2) max_aggregation (read only)
+
+Show maxium allowed instances which can be aggregated for this device. Maxium
+aggregation could be dynamic changed by vendor driver.
+
 Mediated device Hot plug
 ------------------------
 
-- 
2.25.1