Re: [PATCH v8 3/6] LoongArch: KVM: Add cpucfg area for kvm hypervisor

[kernel test robot <lkp@intel.com>]

Hi Bibo,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 5eb4573ea63d0c83bf58fb7c243fc2c2b6966c02]

url:    https://github.com/intel-lab-lkp/linux/commits/Bibo-Mao/LoongArch-smp-Refine-some-ipi-functions-on-LoongArch-platform/20240428-180850
base:   5eb4573ea63d0c83bf58fb7c243fc2c2b6966c02
patch link:    https://lore.kernel.org/r/20240428100518.1642324-4-maobibo%40loongson.cn
patch subject: [PATCH v8 3/6] LoongArch: KVM: Add cpucfg area for kvm hypervisor
config: loongarch-defconfig (https://download.01.org/0day-ci/archive/20240429/202404290016.T9p5GhVr-lkp@intel.com/config)
compiler: loongarch64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240429/202404290016.T9p5GhVr-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202404290016.T9p5GhVr-lkp@intel.com/

All warnings (new ones prefixed by >>):

   arch/loongarch/kvm/exit.c: In function 'kvm_emu_cpucfg':
>> arch/loongarch/kvm/exit.c:213:23: warning: variable 'plv' set but not used [-Wunused-but-set-variable]
     213 |         unsigned long plv;
         |                       ^~~


vim +/plv +213 arch/loongarch/kvm/exit.c

   208	
   209	static int kvm_emu_cpucfg(struct kvm_vcpu *vcpu, larch_inst inst)
   210	{
   211		int rd, rj;
   212		unsigned int index;
 > 213		unsigned long plv;
   214	
   215		rd = inst.reg2_format.rd;
   216		rj = inst.reg2_format.rj;
   217		++vcpu->stat.cpucfg_exits;
   218		index = vcpu->arch.gprs[rj];
   219	
   220		/*
   221		 * By LoongArch Reference Manual 2.2.10.5
   222		 * Return value is 0 for undefined cpucfg index
   223		 *
   224		 * Disable preemption since hw gcsr is accessed
   225		 */
   226		preempt_disable();
   227		plv = kvm_read_hw_gcsr(LOONGARCH_CSR_CRMD) >> CSR_CRMD_PLV_SHIFT;
   228		switch (index) {
   229		case 0 ... (KVM_MAX_CPUCFG_REGS - 1):
   230			vcpu->arch.gprs[rd] = vcpu->arch.cpucfg[index];
   231			break;
   232		case CPUCFG_KVM_SIG:
   233			/* Cpucfg emulation between 0x40000000 -- 0x400000ff */
   234			vcpu->arch.gprs[rd] = *(unsigned int *)KVM_SIGNATURE;
   235			break;
   236		default:
   237			vcpu->arch.gprs[rd] = 0;
   238			break;
   239		}
   240	
   241		preempt_enable();
   242		return EMULATE_DONE;
   243	}
   244	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki