Hi Peter, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on vhost/linux-next] [also build test WARNING on linus/master v5.7-rc7] [cannot apply to kvm/linux-next tip/auto-latest linux/master next-20200522] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Peter-Xu/KVM-Dirty-ring-interfac... base: https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next :::::: branch date: 2 days ago :::::: commit date: 2 days ago compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 reproduce (this is a W=1 build): # 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: kbuild test robot <lkp(a)intel.com&gt; cppcheck warnings: (new ones prefixed by >>) return false; ^ arch/x86/kvm/mmu/mmu.c:3725:9: warning: Redundant initialization for 'root'. The initialized value is overwritten before it is read. [redundantInitialization] root = __pa(sp->spt); ^ arch/x86/kvm/mmu/mmu.c:3715:15: note: root is initialized hpa_t root = vcpu->arch.mmu->pae_root[i]; ^ arch/x86/kvm/mmu/mmu.c:3725:9: note: root is overwritten root = __pa(sp->spt); ^ arch/x86/kvm/mmu/mmu.c:3769:8: warning: Redundant initialization for 'root'. The initialized value is overwritten before it is read. [redundantInitialization] root = __pa(sp->spt); ^ arch/x86/kvm/mmu/mmu.c:3758:14: note: root is initialized hpa_t root = vcpu->arch.mmu->root_hpa; ^ arch/x86/kvm/mmu/mmu.c:3769:8: note: root is overwritten root = __pa(sp->spt); ^ arch/x86/kvm/mmu/mmu.c:4670:15: warning: Clarify calculation precedence for '&' and '?'. [clarifyCalculation] const u8 x = BYTE_MASK(ACC_EXEC_MASK); ^ arch/x86/kvm/mmu/mmu.c:4671:15: warning: Clarify calculation precedence for '&' and '?'. [clarifyCalculation] const u8 w = BYTE_MASK(ACC_WRITE_MASK); ^ arch/x86/kvm/mmu/mmu.c:4672:15: warning: Clarify calculation precedence for '&' and '?'. [clarifyCalculation] const u8 u = BYTE_MASK(ACC_USER_MASK); # https://github.com/0day-ci/linux/commit/2c23bd2b96e30ae3814e3e56f01a62341... git remote add linux-review https://github.com/0day-ci/linux git remote update linux-review git checkout 2c23bd2b96e30ae3814e3e56f01a6234131cb531 vim +1280 arch/x86/kvm/mmu/mmu.c b8e8c8303ff28c arch/x86/kvm/mmu.c Paolo Bonzini 2019-11-04 1269 5d163b1c9d6e55 arch/x86/kvm/mmu.c Xiao Guangrong 2011-03-09 1270 static struct kvm_memory_slot * 5d163b1c9d6e55 arch/x86/kvm/mmu.c Xiao Guangrong 2011-03-09 1271 gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn, 5d163b1c9d6e55 arch/x86/kvm/mmu.c Xiao Guangrong 2011-03-09 1272 bool no_dirty_log) 05da45583de9b3 arch/x86/kvm/mmu.c Marcelo Tosatti 2008-02-23 1273 { 05da45583de9b3 arch/x86/kvm/mmu.c Marcelo Tosatti 2008-02-23 1274 struct kvm_memory_slot *slot; 5d163b1c9d6e55 arch/x86/kvm/mmu.c Xiao Guangrong 2011-03-09 1275 54bf36aac52031 arch/x86/kvm/mmu.c Paolo Bonzini 2015-04-08 1276 slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn); 91b0d268a59dd9 arch/x86/kvm/mmu/mmu.c Paolo Bonzini 2020-01-21 1277 if (!slot || slot->flags & KVM_MEMSLOT_INVALID) 91b0d268a59dd9 arch/x86/kvm/mmu/mmu.c Paolo Bonzini 2020-01-21 1278 return NULL; 2c23bd2b96e30a arch/x86/kvm/mmu/mmu.c Peter Xu 2020-05-23 1279 if (no_dirty_log && kvm_slot_dirty_track_enabled(slot)) 2c23bd2b96e30a arch/x86/kvm/mmu/mmu.c Peter Xu 2020-05-23 @1280 return false; 5d163b1c9d6e55 arch/x86/kvm/mmu.c Xiao Guangrong 2011-03-09 1281 5d163b1c9d6e55 arch/x86/kvm/mmu.c Xiao Guangrong 2011-03-09 1282 return slot; 5d163b1c9d6e55 arch/x86/kvm/mmu.c Xiao Guangrong 2011-03-09 1283 } 5d163b1c9d6e55 arch/x86/kvm/mmu.c Xiao Guangrong 2011-03-09 1284 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org