Hi Andy, I love your patch! Perhaps something to improve: [auto build test WARNING on tip/auto-latest] [also build test WARNING on xen-tip/linux-next v5.8-rc5 next-20200717] [cannot apply to tip/x86/core] [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/Andy-Lutomirski/x86-ioperm-Fix-i... base: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 8b68f1cda59dc238dc67989c8ac3fa95873f89ed config: x86_64-randconfig-s021-20200717 (attached as .config) compiler: gcc-9 (Debian 9.3.0-14) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.2-49-g707c5017-dirty # save the attached .config to linux build tree make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) vim +876 arch/x86/xen/enlighten_pv.c 871 872 #ifdef CONFIG_X86_IOPL_IOPERM 873 static void xen_invalidate_io_bitmap(void) 874 { 875 struct physdev_set_iobitmap iobitmap = { 877 .nr_ports = 0, 878 }; 879 880 native_tss_invalidate_io_bitmap(); 881 HYPERVISOR_physdev_op(PHYSDEVOP_set_iobitmap, &iobitmap); 882 } 883 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org