tree: https://github.com/intel/tdx.git guest head: 41fe88a1b3c28543f49fa6ed9e0e9b6650ed7614 commit: 112748701181f3a7ab49d21bcf7920b983b05af2 [104/144] x86/tdx: Use direct paravirt call for wrmsrl config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20211208/202112080508.FqEbBAvi-lk...) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/intel/tdx/commit/112748701181f3a7ab49d21bcf7920b983b05af2 git remote add intel-tdx https://github.com/intel/tdx.git git fetch --no-tags intel-tdx guest git checkout 112748701181f3a7ab49d21bcf7920b983b05af2 # save the config file to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/kernel/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): arch/x86/kernel/tdx.c:268:5: warning: no previous prototype for 'tdx_hcall_set_notify_intr' [-Wmissing-prototypes] 268 | int tdx_hcall_set_notify_intr(u8 vector) | ^~~~~~~~~~~~~~~~~~~~~~~~~ 491 | void notrace tdx_write_msr(unsigned int msr, u32 low, u32 high) | ^~~~~~~~~~~~~ vim +/tdx_write_msr +491 arch/x86/kernel/tdx.c 490 492 { 493 if (tdx_fast_tdcall_path_msr(msr)) 494 tdx_write_msr_safe(msr, low, high); 495 else 496 native_write_msr(msr, low, high); 497 } 498 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org