Hi, Here is the V2 for supporting kexec kernel efi runtime. Per pervious discussion I pass the 1st kernel efi runtime mapping via setup_data to 2nd kernel. Besides of the runtime mapping info I also pass the fw_vendor, runtime, config table, smbios physical address in setup_data. EFI spec mentioned fw_vendor, runtime, config table addresses will be converted to virt address after entering virtual mode, but we will use it as physical address in efi_init. For smbios EFI spec did not mention about the address updating, but during my test on a HP workstation, the bios will convert it to Virt addr, thus pass it in setup_data as well. For fw_vendor, runtime, config table, I export them in /sys/firmware/ efi/systab, smbios is already in that file. For efi runtime mapping I add a new directory /sys/firmware/efi/ efi-runtime-map/ like below [dave at darkstar ~]$ tree /sys/firmware/efi/efi-runtime-map/ /sys/firmware/efi/efi-runtime-map/ ????????? 0 ??????? ????????? attribute ??????? ????????? num_pages ??????? ????????? phys_addr ??????? ????????? type ??????? ????????? virt_addr ????????? 1 ??????? ????????? attribute ??????? ????????? num_pages ??????? ????????? phys_addr ??????? ????????? type ??????? ????????? virt_addr [snip] kexec-tools will assemble them as setup_data and pass to 2nd kernel. I will send userspace patches as well. Limitation is I only write support for x86_64, test on below machines: Lenovo thinkpad t420 Dell inspiron 14 - 3421 HP Z420 workstation Qemu + OVMF Please help to review the patches. The patches are based on matt's efi master tree Changes from v1: add one flag in xloadflags, so kexec-tools can safely load old kernel without efi support. coding style fixes function name for map phys_addr to fixed virt_addr Add ABI documentation for sysfs files -- Thanks Dave