Hi Nicholas, I love your patch! Yet something to improve: [auto build test ERROR on powerpc/next] [also build test ERROR on linus/master v5.14-rc5 next-20210811] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Nicholas-Piggin/KVM-PPC-Book3S-H... base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next config: powerpc64-randconfig-r024-20210811 (attached as .config) compiler: powerpc-linux-gcc (GCC) 10.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/0day-ci/linux/commit/b5149d8c735b6802aa0433a0cecc73e4d... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Nicholas-Piggin/KVM-PPC-Book3S-HV-P9-entry-exit-optimisations/20210812-000748 git checkout b5149d8c735b6802aa0433a0cecc73e4d943e795 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross ARCH=powerpc64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): 596 | void save_user_regs_kvm(void) | ^~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors vim +/save_user_regs_kvm +596 arch/powerpc/kernel/process.c 595 597 { 598 unsigned long usermsr; 599 600 if (!current->thread.regs) 601 return; 602 603 usermsr = current->thread.regs->msr; 604 605 if (usermsr & MSR_FP) 606 save_fpu(current); 607 608 if (usermsr & MSR_VEC) 609 save_altivec(current); 610 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org