Hi, kernel test robot noticed the following build warnings: [auto build test WARNING on kvm/queue] [also build test WARNING on kvm/next mst-vhost/linux-next linus/master v6.17-rc1 next-20250815] [cannot apply to kvm/linux-next] [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#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/fangyu-yu-linux-alibaba-com/RISC-V-KVM-Write-hgatp-register-with-valid-mode-bits/20250816-153513 base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue patch link: https://lore.kernel.org/r/20250816073234.77646-1-fangyu.yu%40linux.alibaba.com patch subject: [PATCH] RISC-V: KVM: Write hgatp register with valid mode bits config: riscv-allyesconfig (https://download.01.org/0day-ci/archive/20250817/202508171655.76Ifmphq-lkp@xxxxxxxxx/config) compiler: clang version 16.0.6 (https://github.com/llvm/llvm-project 7cbf1a2591520c2491aa35339f227775f4d3adf6) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250817/202508171655.76Ifmphq-lkp@xxxxxxxxx/reproduce) 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@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-kbuild-all/202508171655.76Ifmphq-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): arch/riscv/kvm/vmid.c:31:24: error: call to undeclared function 'kvm_riscv_gstage_mode'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] csr_write(CSR_HGATP, (kvm_riscv_gstage_mode() << HGATP_MODE_SHIFT) | HGATP_VMID); ^ >> arch/riscv/kvm/vmid.c:31:48: warning: shift count >= width of type [-Wshift-count-overflow] csr_write(CSR_HGATP, (kvm_riscv_gstage_mode() << HGATP_MODE_SHIFT) | HGATP_VMID); ^ ~~~~~~~~~~~~~~~~ arch/riscv/include/asm/csr.h:538:38: note: expanded from macro 'csr_write' unsigned long __v = (unsigned long)(val); \ ^~~ 1 warning and 1 error generated. vim +31 arch/riscv/kvm/vmid.c 24 25 void __init kvm_riscv_gstage_vmid_detect(void) 26 { 27 unsigned long old; 28 29 /* Figure-out number of VMID bits in HW */ 30 old = csr_read(CSR_HGATP); > 31 csr_write(CSR_HGATP, (kvm_riscv_gstage_mode() << HGATP_MODE_SHIFT) | HGATP_VMID); 32 vmid_bits = csr_read(CSR_HGATP); 33 vmid_bits = (vmid_bits & HGATP_VMID) >> HGATP_VMID_SHIFT; 34 vmid_bits = fls_long(vmid_bits); 35 csr_write(CSR_HGATP, old); 36 37 /* We polluted local TLB so flush all guest TLB */ 38 kvm_riscv_local_hfence_gvma_all(); 39 40 /* We don't use VMID bits if they are not sufficient */ 41 if ((1UL << vmid_bits) < num_possible_cpus()) 42 vmid_bits = 0; 43 } 44 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
