Hi Marc, FYI, the error/warning still remains. tree: https://android.googlesource.com/kernel/common android12-5.10-2021-09 head: 0a07ca4e42c839ccc8cfcfa63078c9cb580c7d3b commit: 194fd166b5d5f6694047b45dc409f9620a8a9646 [6732/10851] BACKPORT: FROMGIT: KVM: arm64: Trap host SVE accesses when the FPSIMD state is dirty config: arm64-buildonly-randconfig-r004-20211004 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c0039de2953d15815448b4b3c3bafb45607781e0) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu git remote add android-common https://android.googlesource.com/kernel/common git fetch --no-tags android-common android12-5.10-2021-09 git checkout 194fd166b5d5f6694047b45dc409f9620a8a9646 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=arm64 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/arm64/kvm/hyp/nvhe/hyp-main.c:7: arch/arm64/kvm/hyp/include/hyp/switch.h:216:2: error: implicit declaration of function 'sve_cond_update_zcr_vq' [-Werror,-Wimplicit-function-declaration] sve_cond_update_zcr_vq(vcpu_sve_max_vq(vcpu) - 1, SYS_ZCR_EL2); ^ sve_cond_update_zcr_vq(ZCR_ELx_LEN_MASK, SYS_ZCR_EL2); ^ arch/arm64/kvm/hyp/nvhe/hyp-main.c:233:6: warning: no previous prototype for function 'handle_trap' [-Wmissing-prototypes] void handle_trap(struct kvm_cpu_context *host_ctxt) ^ arch/arm64/kvm/hyp/nvhe/hyp-main.c:233:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void handle_trap(struct kvm_cpu_context *host_ctxt) ^ static 1 warning and 2 errors generated. vim +/sve_cond_update_zcr_vq +245 arch/arm64/kvm/hyp/nvhe/hyp-main.c 232 233 void handle_trap(struct kvm_cpu_context *host_ctxt) 234 { 235 u64 esr = read_sysreg_el2(SYS_ESR); 236 237 switch (ESR_ELx_EC(esr)) { 238 case ESR_ELx_EC_HVC64: 239 handle_host_hcall(host_ctxt); 240 break; 241 case ESR_ELx_EC_SMC64: 242 handle_host_smc(host_ctxt); 243 break; 244 case ESR_ELx_EC_SVE: --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org