tree: git://git.infradead.org/users/hch/misc.git um-set_fs head: 62ef80add97f4b90b4435670fcd5c0a6bd424fad commit: bc1802ed3414136e0dfe2ea0a747aca59dc33b5c [1/2] x86/mtrr: don't include <asm/memtype.h> for !CONFIG_MTRR config: x86_64-randconfig-a006-20211214 (https://download.01.org/0day-ci/archive/20211214/202112142126.XDd02OOu-lk...) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): git remote add hch-misc git://git.infradead.org/users/hch/misc.git git fetch --no-tags hch-misc um-set_fs git checkout bc1802ed3414136e0dfe2ea0a747aca59dc33b5c # 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/kvm/ 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 >>): In file included from arch/x86/include/asm/kvm_host.h:31, from include/linux/kvm_host.h:39, from arch/x86/kvm/mmu/spte.c:12: arch/x86/include/asm/mtrr.h: In function 'mtrr_bp_init': arch/x86/include/asm/mtrr.h:89:2: error: implicit declaration of function 'pat_disable'; did you mean 'ptrace_disable'? [-Werror=implicit-function-declaration] 89 | pat_disable("PAT support disabled because CONFIG_MTRR is disabled in the kernel."); | ^~~~~~~~~~~ | ptrace_disable arch/x86/kvm/mmu/spte.c: In function 'kvm_is_mmio_pfn': 85 | (!pat_enabled() || pat_pfn_immune_to_uc_mtrr(pfn)); | ^~~~~~~~~~~ | kasan_enabled 85 | (!pat_enabled() || pat_pfn_immune_to_uc_mtrr(pfn)); | ^~~~~~~~~~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +85 arch/x86/kvm/mmu/spte.c 5a9624affe7c74 Paolo Bonzini 2020-10-16 70 5a9624affe7c74 Paolo Bonzini 2020-10-16 71 static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) 5a9624affe7c74 Paolo Bonzini 2020-10-16 72 { 5a9624affe7c74 Paolo Bonzini 2020-10-16 73 if (pfn_valid(pfn)) 5a9624affe7c74 Paolo Bonzini 2020-10-16 74 return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn)) && 5a9624affe7c74 Paolo Bonzini 2020-10-16 75 /* 5a9624affe7c74 Paolo Bonzini 2020-10-16 76 * Some reserved pages, such as those from NVDIMM 5a9624affe7c74 Paolo Bonzini 2020-10-16 77 * DAX devices, are not for MMIO, and can be mapped 5a9624affe7c74 Paolo Bonzini 2020-10-16 78 * with cached memory type for better performance. 5a9624affe7c74 Paolo Bonzini 2020-10-16 79 * However, the above check misconceives those pages 5a9624affe7c74 Paolo Bonzini 2020-10-16 80 * as MMIO, and results in KVM mapping them with UC 5a9624affe7c74 Paolo Bonzini 2020-10-16 81 * memory type, which would hurt the performance. 5a9624affe7c74 Paolo Bonzini 2020-10-16 82 * Therefore, we check the host memory type in addition 5a9624affe7c74 Paolo Bonzini 2020-10-16 83 * and only treat UC/UC-/WC pages as MMIO. 5a9624affe7c74 Paolo Bonzini 2020-10-16 84 */ 5a9624affe7c74 Paolo Bonzini 2020-10-16 @85 (!pat_enabled() || pat_pfn_immune_to_uc_mtrr(pfn)); 5a9624affe7c74 Paolo Bonzini 2020-10-16 86 5a9624affe7c74 Paolo Bonzini 2020-10-16 87 return !e820__mapped_raw_any(pfn_to_hpa(pfn), 5a9624affe7c74 Paolo Bonzini 2020-10-16 88 pfn_to_hpa(pfn + 1) - 1, 5a9624affe7c74 Paolo Bonzini 2020-10-16 89 E820_TYPE_RAM); 5a9624affe7c74 Paolo Bonzini 2020-10-16 90 } 5a9624affe7c74 Paolo Bonzini 2020-10-16 91 :::::: The code at line 85 was first introduced by commit :::::: 5a9624affe7c7498fb395879d9bb613628e89e60 KVM: mmu: extract spte.h and spte.c :::::: TO: Paolo Bonzini <pbonzini(a)redhat.com&gt; :::::: CC: Paolo Bonzini <pbonzini(a)redhat.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org