| system_ss.add(when: ['CONFIG_XEN_BUS'], if_true: files( | 
 |   'xen-backend.c', | 
 |   'xen-bus-helper.c', | 
 |   'xen-bus.c', | 
 |   'xen-legacy-backend.c', | 
 |   'xen_devconfig.c', | 
 |   'xen_pvdev.c', | 
 | )) | 
 |  | 
 | system_ss.add(when: ['CONFIG_XEN', xen], if_true: files( | 
 |   'xen-operations.c', | 
 | )) | 
 |  | 
 | xen_specific_ss = ss.source_set() | 
 | xen_specific_ss.add(files( | 
 |   'xen-mapcache.c', | 
 |   'xen-hvm-common.c', | 
 | )) | 
 | if have_xen_pci_passthrough | 
 |   xen_specific_ss.add(files( | 
 |     'xen-host-pci-device.c', | 
 |     'xen_pt.c', | 
 |     'xen_pt_config_init.c', | 
 |     'xen_pt_graphics.c', | 
 |     'xen_pt_load_rom.c', | 
 |     'xen_pt_msi.c', | 
 |   )) | 
 | else | 
 |   xen_specific_ss.add(files('xen_pt_stub.c')) | 
 | endif | 
 |  | 
 | specific_ss.add_all(when: ['CONFIG_XEN', xen], if_true: xen_specific_ss) |