The pcie-switch-downstream-port and pcie-root-port controllers have
only a single slot, numbered 0, and the greate majority of all guest
PCI devices are plugged into function 0 of whatever slot they're
using. The parser makes these optional, setting them to 0 when not
specified, and it's logical for the schema to also make them optional.
<attribute name="bus">
<ref name="pciBus"/>
</attribute>
- <attribute name="slot">
- <ref name="pciSlot"/>
- </attribute>
- <attribute name="function">
- <ref name="pciFunc"/>
- </attribute>
+ <optional>
+ <attribute name="slot">
+ <ref name="pciSlot"/>
+ </attribute>
+ </optional>
+ <optional>
+ <attribute name="function">
+ <ref name="pciFunc"/>
+ </attribute>
+ </optional>
<optional>
<attribute name="multifunction">
<ref name="virOnOff"/>