[PATCH v2 5/5] s390: doc: Update doc

[Jason J. Herne]

fix me

Signed-off-by: Jason J. Herne <jjherne@xxxxxxxxxxxxx>
---
 Documentation/arch/s390/vfio-ap.rst | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/Documentation/arch/s390/vfio-ap.rst b/Documentation/arch/s390/vfio-ap.rst
index 929ee1c1c940..af5ef60355a2 100644
--- a/Documentation/arch/s390/vfio-ap.rst
+++ b/Documentation/arch/s390/vfio-ap.rst
@@ -380,6 +380,33 @@ matrix device.
     control_domains:
       A read-only file for displaying the control domain numbers assigned to the
       vfio_ap mediated device.
+    ap_config:
+        A read/write file that, when written to, allows the entire vfio_ap mediated
+        device's ap configuration to be replaced in one shot. Three masks are given,
+        one for adapters, one for domains, and one for control domains. If the
+        given state cannot be set, then no changes are made to the vfio-ap
+        mediated device.
+
+        The format of the data written to ap_config is as follows:
+        {amask},{dmask},{cmask}\n
+
+        \n is a newline character.
+
+        amask, dmask, and cmask are masks identifying which adapters, domains,
+        and control domains should be assigned to the mediated device.
+
+        The format of a mask is as follows:
+        0xNN..NN
+
+        Where NN..NN is 64 hexadecimal characters representing a 256-bit value.
+        The leftmost (highest order) bit represents adapter/domain 0.
+
+        For an example set of masks that represent your mdev's current
+        configuration, simply cat ap_config.
+
+        This attribute is intended to be used by automation. End users would be
+        better served using the respective assign/unassign attributes for
+        adapters, domains, and control domains.
 
 * functions:
 
-- 
2.41.0