Re: [PATCH v3 3/3] KVM: VMX: Advertise PMU LBRs if and only if perf supports LBRs

From: kernel test robot <lkp@intel.com>
To: Sean Christopherson <seanjc@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: llvm@lists.linux.dev, kbuild-all@lists.01.org,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, Like Xu <like.xu.linux@gmail.com>
Subject: Re: [PATCH v3 3/3] KVM: VMX: Advertise PMU LBRs if and only if perf supports LBRs
Date: Wed, 31 Aug 2022 17:49:27 +0800	[thread overview]
Message-ID: <202208311746.VAzmtgNx-lkp@intel.com> (raw)
In-Reply-To: <20220831000051.4015031-4-seanjc@google.com>

Hi Sean,

I love your patch! Yet something to improve:

[auto build test ERROR on 372d07084593dc7a399bf9bee815711b1fb1bcf2]

url:    https://github.com/intel-lab-lkp/linux/commits/Sean-Christopherson/KVM-x86-Intel-LBR-related-perf-cleanups/20220831-080309
base:   372d07084593dc7a399bf9bee815711b1fb1bcf2
config: x86_64-randconfig-a012 (https://download.01.org/0day-ci/archive/20220831/202208311746.VAzmtgNx-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
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
        # https://github.com/intel-lab-lkp/linux/commit/094f42374997562fff3f9f9637ec9aa8257490a0
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Sean-Christopherson/KVM-x86-Intel-LBR-related-perf-cleanups/20220831-080309
        git checkout 094f42374997562fff3f9f9637ec9aa8257490a0
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 prepare

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from arch/x86/kernel/asm-offsets.c:22:
   In file included from arch/x86/kernel/../kvm/vmx/vmx.h:11:
>> arch/x86/kernel/../kvm/vmx/capabilities.h:416:2: error: implicit declaration of function 'x86_perf_get_lbr' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
           x86_perf_get_lbr(&lbr);
           ^
   1 error generated.
   make[2]: *** [scripts/Makefile.build:117: arch/x86/kernel/asm-offsets.s] Error 1
   make[2]: Target '__build' not remade because of errors.
   make[1]: *** [Makefile:1207: prepare0] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:222: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.

vim +/x86_perf_get_lbr +416 arch/x86/kernel/../kvm/vmx/capabilities.h

   403	
   404	static inline u64 vmx_get_perf_capabilities(void)
   405	{
   406		u64 perf_cap = PMU_CAP_FW_WRITES;
   407		struct x86_pmu_lbr lbr;
   408		u64 host_perf_cap = 0;
   409	
   410		if (!enable_pmu)
   411			return 0;
   412	
   413		if (boot_cpu_has(X86_FEATURE_PDCM))
   414			rdmsrl(MSR_IA32_PERF_CAPABILITIES, host_perf_cap);
   415	
 > 416		x86_perf_get_lbr(&lbr);
   417		if (lbr.nr)
   418			perf_cap |= host_perf_cap & PMU_CAP_LBR_FMT;
   419	
   420		if (vmx_pebs_supported()) {
   421			perf_cap |= host_perf_cap & PERF_CAP_PEBS_MASK;
   422			if ((perf_cap & PERF_CAP_PEBS_FORMAT) < 4)
   423				perf_cap &= ~PERF_CAP_PEBS_BASELINE;
   424		}
   425	
   426		return perf_cap;
   427	}
   428	

-- 
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https://01.org/lkp