Configuring a pass-through DASD

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In the configuration-XML, specify pass-through DASDs as CCW devices that are based on VFIO mediated devices on the host.

Before you begin

On the host, the vfio_ccw device driver must control the DASD, and a VFIO mediated device must be configured for it (see Preparing DASD pass-through devices).

You use the UUID of the mediated device to configure a pass-through DASD.

Procedure

Configure the device as a VFIO mediated device with the hostdev element (see <hostdev>).

hostdev mode attribute: subsystem

hostdev type attribute: mdev

hostdev model attribute: vfio-ccw
Identify the device on the host with the address element as a child of the source element.

address uuid attribute: <uuid>

(see <source> as child element of <hostdev> and <address> as child element of <source>)
Identify the DASD on the virtual server with the address element as a child of the hostdev element.

address type attribute: ccw

address cssid attribute: 0xfe

address ssid attribute: <ssid>

address devno attribute: <devno>

Example

<hostdev mode="subsystem" type="mdev" model="vfio-ccw">
   <source>
      <address uuid="90c6c135-ad44-41d0-b1b7-bae47de48627"/>
   </source>
   <address type="ccw" cssid="0xfe" ssid="0x0" devno="0x00a1"/>
</hostdev>

In the example, the UUID of the mediated device on the host is 90c6c135-ad44-41d0-b1b7-bae47de48627. On the guest, the bus ID of the DASD is 0.0.00a1.