The xen output can only be used by Xen PV guests.
+ edac_report= [HW,EDAC] Control how to report EDAC event
+ Format: {"on" | "off" | "force"}
+ on: enable EDAC to report H/W event. May be overridden
+ by other higher priority error reporting module.
+ off: disable H/W event reporting through EDAC.
+ force: enforce the use of EDAC to report H/W event.
+ default: on.
+
ekgdboc= [X86,KGDB] Allow early kernel console debugging
ekgdboc=kbd
* atapi_dmadir: Enable ATAPI DMADIR bridge support
+ * disable: Disable this device.
+
If there are multiple matching configurations changing
the same attribute, the last one is used.