[libvirt] [PATCH 7/8] docs: documentation for vfio-ccw passthrough

[Shalini Chellathurai Saroja]

Signed-off-by: Shalini Chellathurai Saroja <shalini at linux.vnet.ibm.com>
Reviewed-by: Bjoern Walk <bwalk at linux.vnet.ibm.com>
Reviewed-by: Boris Fiuczynski <fiuczy at linux.vnet.ibm.com>
---
 docs/drvnodedev.html.in   | 21 ++++++++++++++++++++-
 docs/formatdomain.html.in | 20 +++++++++++++++-----
 2 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/docs/drvnodedev.html.in b/docs/drvnodedev.html.in
index 885904d67d..71a8a57b0c 100644
--- a/docs/drvnodedev.html.in
+++ b/docs/drvnodedev.html.in
@@ -335,8 +335,27 @@
 $ ls /sys/class/mdev_bus/<device>/mdev_supported_types</pre>
 
     <p>
+      Before creating a mediated device, unbind the device from the respective
+      device driver, eg. subchannel I/O driver for a CCW device. Then bind the
+      device to the respective VFIO driver. For a CCW device, also unbind the
+      corresponding subchannel of the CCW device from the subchannel I/O driver
+      and then bind the subchannel (instead of the CCW device) to the vfio_ccw
+      driver. The below example shows the unbinding and binding steps for a CCW
+      device.
+    </p>
+
+    <pre>
+device="0.0.1234"
+subchannel="0.0.0123"
+echo $device > /sys/bus/ccw/devices/$device/driver/unbind
+echo $subchannel > /sys/bus/css/devices/$subchannel/driver/unbind
+echo $subchannel > /sys/bus/css/drivers/vfio_ccw/bind
+    </pre>
+
+    <p>
       To manually instantiate a mediated device, use one of the following as a
-      reference:
+      reference. For a CCW device, use the subchannel ID instead of the device
+      ID.
     </p>
 
     <pre>
diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 5e99884dc5..ff8ec25928 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -4308,6 +4308,12 @@
       <address uuid='c2177883-f1bb-47f0-914d-32a22e3a8804'/>
     </source>
     </hostdev>
+    <hostdev mode='subsystem' type='mdev' model='vfio-ccw'>
+    <source>
+      <address uuid='9063cba3-ecef-47b6-abcf-3fef4fdcad85'/>
+    </source>
+    <address type='ccw' cssid='0xfe' ssid='0x0' devno='0x0001'/>
+    </hostdev>
   </devices>
   ...</pre>
 
@@ -4359,10 +4365,13 @@
           <dd>For mediated devices (<span class="since">Since 3.2.0</span>)
           the <code>model</code> attribute specifies the device API which
           determines how the host's vfio driver will expose the device to the
-          guest. Currently, only <code>model='vfio-pci'</code> is supported.
-          There are also some implications on the usage of guest's address type
-          depending on the <code>model</code> attribute, see the
-          <code>address</code> element below.</dd>
+          guest. Currently, <code>model='vfio-pci'</code> and
+          <code>model='vfio-ccw'</code> (<span class="since">Since 4.3.0</span>)
+          is supported. Refer <a href="drvnodedev.html#MDEV">MDEV</a> to create
+          a mediated device on the host. There are also some implications on the
+          usage of guest's address type depending on the <code>model</code>
+          attribute, see the <code>address</code> element below.
+          </dd>
         </dl>
         <p>
           Note: The <code>managed</code> attribute is only used with
@@ -4488,7 +4497,8 @@
       devices defining an allocation of resources on the physical parent device,
       the address type used must conform to the <code>model</code> attribute
       of element <code>hostdev</code>, e.g. any address type other than PCI for
-      <code>vfio-pci</code> device API will result in an error.
+      <code>vfio-pci</code> device API or any address type other than CCW for
+      <code>vfio-ccw</code> device API will result in an error.
       <a href="#elementsAddress">See above</a> for more details on the address
       element.</dd>
       <dt><code>driver</code></dt>
-- 
2.13.4