Hi Ben, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on kvm/queue] [also build test WARNING on tip/master linus/master next-20210506] [cannot apply to linux/master v5.12] [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/Ben-Gardon/Lazily-allocate-memslot-rmaps/20210507-024533 base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue config: x86_64-randconfig-s021-20210506 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.3-341-g8af24329-dirty # https://github.com/0day-ci/linux/commit/43798461d3f4a38ef487d9c626dd0fb13e403328 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Ben-Gardon/Lazily-allocate-memslot-rmaps/20210507-024533 git checkout 43798461d3f4a38ef487d9c626dd0fb13e403328 # save the attached .config to linux build tree make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot sparse warnings: (new ones prefixed by >>) arch/x86/kvm/x86.c:10926:17: sparse: sparse: incompatible types in comparison expression (different address spaces): arch/x86/kvm/x86.c:10926:17: sparse: struct kvm_rmap_head [noderef] __rcu * arch/x86/kvm/x86.c:10926:17: sparse: struct kvm_rmap_head * arch/x86/kvm/x86.c: note: in included file (through include/linux/notifier.h, include/linux/memory_hotplug.h, include/linux/mmzone.h, ...): include/linux/srcu.h:182:9: sparse: sparse: context imbalance in 'vcpu_enter_guest' - unexpected unlock >> arch/x86/kvm/x86.c:10971:29: sparse: sparse: marked inline, but without a definition vim +10971 arch/x86/kvm/x86.c db3fe4eb45f355 Takuya Yoshikawa 2012-02-08 10913 11bb59d1c3e83b Ben Gardon 2021-05-06 10914 static int alloc_memslot_rmap(struct kvm_memory_slot *slot, 11bb59d1c3e83b Ben Gardon 2021-05-06 10915 unsigned long npages) 11bb59d1c3e83b Ben Gardon 2021-05-06 10916 { 11bb59d1c3e83b Ben Gardon 2021-05-06 10917 int i; 11bb59d1c3e83b Ben Gardon 2021-05-06 10918 11bb59d1c3e83b Ben Gardon 2021-05-06 10919 for (i = 0; i < KVM_NR_PAGE_SIZES; ++i) { 11bb59d1c3e83b Ben Gardon 2021-05-06 10920 int lpages; 11bb59d1c3e83b Ben Gardon 2021-05-06 10921 int level = i + 1; 11bb59d1c3e83b Ben Gardon 2021-05-06 10922 11bb59d1c3e83b Ben Gardon 2021-05-06 10923 lpages = gfn_to_index(slot->base_gfn + npages - 1, 11bb59d1c3e83b Ben Gardon 2021-05-06 10924 slot->base_gfn, level) + 1; 11bb59d1c3e83b Ben Gardon 2021-05-06 10925 dd56af97c1d2b2 Ben Gardon 2021-05-06 @10926 rcu_assign_pointer(slot->arch.rmap[i], 11bb59d1c3e83b Ben Gardon 2021-05-06 10927 kvcalloc(lpages, sizeof(*slot->arch.rmap[i]), dd56af97c1d2b2 Ben Gardon 2021-05-06 10928 GFP_KERNEL_ACCOUNT)); 11bb59d1c3e83b Ben Gardon 2021-05-06 10929 if (!slot->arch.rmap[i]) 11bb59d1c3e83b Ben Gardon 2021-05-06 10930 goto out_free; 11bb59d1c3e83b Ben Gardon 2021-05-06 10931 } 11bb59d1c3e83b Ben Gardon 2021-05-06 10932 11bb59d1c3e83b Ben Gardon 2021-05-06 10933 return 0; 11bb59d1c3e83b Ben Gardon 2021-05-06 10934 11bb59d1c3e83b Ben Gardon 2021-05-06 10935 out_free: 11bb59d1c3e83b Ben Gardon 2021-05-06 10936 free_memslot_rmap(slot); 11bb59d1c3e83b Ben Gardon 2021-05-06 10937 return -ENOMEM; 11bb59d1c3e83b Ben Gardon 2021-05-06 10938 } 11bb59d1c3e83b Ben Gardon 2021-05-06 10939 43798461d3f4a3 Ben Gardon 2021-05-06 10940 int alloc_all_memslots_rmaps(struct kvm *kvm) 43798461d3f4a3 Ben Gardon 2021-05-06 10941 { 43798461d3f4a3 Ben Gardon 2021-05-06 10942 struct kvm_memslots *slots; 43798461d3f4a3 Ben Gardon 2021-05-06 10943 struct kvm_memory_slot *slot; 43798461d3f4a3 Ben Gardon 2021-05-06 10944 int r = 0; 43798461d3f4a3 Ben Gardon 2021-05-06 10945 int i; 43798461d3f4a3 Ben Gardon 2021-05-06 10946 43798461d3f4a3 Ben Gardon 2021-05-06 10947 if (kvm_memslots_have_rmaps(kvm)) 43798461d3f4a3 Ben Gardon 2021-05-06 10948 return 0; 43798461d3f4a3 Ben Gardon 2021-05-06 10949 43798461d3f4a3 Ben Gardon 2021-05-06 10950 mutex_lock(&kvm->slots_arch_lock); 43798461d3f4a3 Ben Gardon 2021-05-06 10951 for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { 43798461d3f4a3 Ben Gardon 2021-05-06 10952 slots = __kvm_memslots(kvm, i); 43798461d3f4a3 Ben Gardon 2021-05-06 10953 kvm_for_each_memslot(slot, slots) { 43798461d3f4a3 Ben Gardon 2021-05-06 10954 r = alloc_memslot_rmap(slot, slot->npages); 43798461d3f4a3 Ben Gardon 2021-05-06 10955 if (r) { 43798461d3f4a3 Ben Gardon 2021-05-06 10956 mutex_unlock(&kvm->slots_arch_lock); 43798461d3f4a3 Ben Gardon 2021-05-06 10957 return r; 43798461d3f4a3 Ben Gardon 2021-05-06 10958 } 43798461d3f4a3 Ben Gardon 2021-05-06 10959 } 43798461d3f4a3 Ben Gardon 2021-05-06 10960 } 43798461d3f4a3 Ben Gardon 2021-05-06 10961 43798461d3f4a3 Ben Gardon 2021-05-06 10962 /* 43798461d3f4a3 Ben Gardon 2021-05-06 10963 * memslots_have_rmaps is set and read in different lock contexts, 43798461d3f4a3 Ben Gardon 2021-05-06 10964 * so protect it with smp_load/store. 43798461d3f4a3 Ben Gardon 2021-05-06 10965 */ 43798461d3f4a3 Ben Gardon 2021-05-06 10966 smp_store_release(&kvm->arch.memslots_have_rmaps, true); 43798461d3f4a3 Ben Gardon 2021-05-06 10967 mutex_unlock(&kvm->slots_arch_lock); 43798461d3f4a3 Ben Gardon 2021-05-06 10968 return 0; 43798461d3f4a3 Ben Gardon 2021-05-06 10969 } 43798461d3f4a3 Ben Gardon 2021-05-06 10970 fac0d516d29b67 Ben Gardon 2021-05-06 @10971 bool kvm_memslots_have_rmaps(struct kvm *kvm) fac0d516d29b67 Ben Gardon 2021-05-06 10972 { 43798461d3f4a3 Ben Gardon 2021-05-06 10973 /* 43798461d3f4a3 Ben Gardon 2021-05-06 10974 * memslots_have_rmaps is set and read in different lock contexts, 43798461d3f4a3 Ben Gardon 2021-05-06 10975 * so protect it with smp_load/store. 43798461d3f4a3 Ben Gardon 2021-05-06 10976 */ 43798461d3f4a3 Ben Gardon 2021-05-06 10977 return smp_load_acquire(&kvm->arch.memslots_have_rmaps); fac0d516d29b67 Ben Gardon 2021-05-06 10978 } fac0d516d29b67 Ben Gardon 2021-05-06 10979 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org