tree: https://gitee.com/openeuler/kernel.git OLK-6.6 head: 2f6a2b7160d59b59ef2bd08614200d0a2219b54e commit: 958959657133b04448125ddf9c89c669f7eee066 [3064/3064] KVM: arm64: Allow userspace to change the implementation ID registers config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20251030/202510300607.beN0C3BL-lkp@i...) compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251030/202510300607.beN0C3BL-lkp@i...) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202510300607.beN0C3BL-lkp@intel.com/ All warnings (new ones prefixed by >>):

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arch/arm64/kvm/arm.c:253:7: warning: variable 'r' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] 253 | if (!kvm->created_vcpus) { | ^~~~~~~~~~~~~~~~~~~ arch/arm64/kvm/arm.c:297:9: note: uninitialized use occurs here 297 | return r; | ^ arch/arm64/kvm/arm.c:253:3: note: remove the 'if' if its condition is always true 253 | if (!kvm->created_vcpus) { | ^~~~~~~~~~~~~~~~~~~~~~~~ arch/arm64/kvm/arm.c:225:7: note: initialize the variable 'r' to silence this warning 225 | int r; | ^ | = 0 arch/arm64/kvm/arm.c:596:5: warning: no previous prototype for function 'kvm_arch_rec_init' [-Wmissing-prototypes] 596 | int kvm_arch_rec_init(struct kvm_vcpu_arch *vcpu_arch) | ^ arch/arm64/kvm/arm.c:596:1: note: declare 'static' if the function is not intended to be used outside of this translation unit 596 | int kvm_arch_rec_init(struct kvm_vcpu_arch *vcpu_arch) | ^ | static 2 warnings generated.

vim +253 arch/arm64/kvm/arm.c 221 222 int kvm_vm_ioctl_enable_cap(struct kvm *kvm, 223 struct kvm_enable_cap *cap) 224 { 225 int r; 226 u64 new_cap; 227 228 if (cap->flags) 229 return -EINVAL; 230 231 switch (cap->cap) { 232 case KVM_CAP_ARM_NISV_TO_USER: 233 r = 0; 234 set_bit(KVM_ARCH_FLAG_RETURN_NISV_IO_ABORT_TO_USER, 235 &kvm->arch.flags); 236 break; 237 case KVM_CAP_ARM_MTE: 238 mutex_lock(&kvm->lock); 239 if (!system_supports_mte() || kvm->created_vcpus) { 240 r = -EINVAL; 241 } else { 242 r = 0; 243 set_bit(KVM_ARCH_FLAG_MTE_ENABLED, &kvm->arch.flags); 244 } 245 mutex_unlock(&kvm->lock); 246 break; 247 case KVM_CAP_ARM_SYSTEM_SUSPEND: 248 r = 0; 249 set_bit(KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED, &kvm->arch.flags); 250 break; 251 case KVM_CAP_ARM_WRITABLE_IMP_ID_REGS: 252 mutex_lock(&kvm->lock);

253 if (!kvm->created_vcpus) { 254 r = 0; 255 set_bit(KVM_ARCH_FLAG_WRITABLE_IMP_ID_REGS, &kvm->arch.flags); 256 } 257 mutex_unlock(&kvm->lock); 258 break; 259 case KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE: 260 new_cap = cap->args[0]; 261 262 mutex_lock(&kvm->slots_lock); 263 /* 264 * To keep things simple, allow changing the chunk 265 * size only when no memory slots have been created. 266 */ 267 if (!kvm_are_all_memslots_empty(kvm)) { 268 r = -EINVAL; 269 } else if (new_cap && !kvm_is_block_size_supported(new_cap)) { 270 r = -EINVAL; 271 } else { 272 r = 0; 273 kvm->arch.mmu.split_page_chunk_size = new_cap; 274 } 275 mutex_unlock(&kvm->slots_lock); 276 break; 277 #ifdef CONFIG_ARM64_HDBSS 278 case KVM_CAP_ARM_HW_DIRTY_STATE_TRACK: 279 r = kvm_cap_arm_enable_hdbss(kvm, cap); 280 break; 281 #endif 282 #ifdef CONFIG_ARM64_HISI_IPIV 283 case KVM_CAP_ARM_HISI_IPIV: 284 r = kvm_hisi_ipiv_enable_cap(kvm, cap); 285 break; 286 #endif 287 case KVM_CAP_ARM_RME: 288 mutex_lock(&kvm->lock); 289 r = kvm_realm_enable_cap(kvm, cap); 290 mutex_unlock(&kvm->lock); 291 break; 292 default: 293 r = -EINVAL; 294 break; 295 } 296 297 return r; 298 } 299

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