tree: https://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git sev-es-kexec head: 3467dc3cdbe65c619cd9b5c8db47da63b0655300 commit: 441bc34569808f9c19fcbe8c1b7625402b9b9786 [2/12] x86/kexec/64: Forbid kexec when running as an SEV-ES guest config: x86_64-randconfig-c022-20210702 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git/commit/?id=441bc34569808f9c19fcbe8c1b7625402b9b9786 git remote add joro https://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git git fetch --no-tags joro sev-es-kexec git checkout 441bc34569808f9c19fcbe8c1b7625402b9b9786 # save the attached .config to linux build tree make W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): >> arch/x86/kernel/machine_kexec_64.c:627:6: warning: no previous prototype for 'arch_kexec_supported' [-Wmissing-prototypes] 627 | bool arch_kexec_supported(void) | ^~~~~~~~~~~~~~~~~~~~ vim +/arch_kexec_supported +627 arch/x86/kernel/machine_kexec_64.c 623 624 /* 625 * Kexec is not supported in SEV-ES guests yet 626 */ > 627 bool arch_kexec_supported(void) --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org