linux-kernel - 答复: [PATCH] [v4] KVM: X86: support APERF/MPERF registers

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Message-ID: <279090c97595496db37658c4abab1ca4@baidu.com>
Date:   Fri, 8 May 2020 01:57:43 +0000
From:   "Li,Rongqing" <lirongqing@...du.com>
To:     kbuild test robot <lkp@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>, "hpa@...or.com" <hpa@...or.com>,
        "bp@...en8.de" <bp@...en8.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "jmattson@...gle.com" <jmattson@...gle.com>,
        "wanpengli@...cent.com" <wanpengli@...cent.com>,
        "vkuznets@...hat.com" <vkuznets@...hat.com>,
        "sean.j.christopherson@...el.com" <sean.j.christopherson@...el.com>,
        "pbonzini@...hat.com" <pbonzini@...hat.com>,
        "xiaoyao.li@...el.com" <xiaoyao.li@...el.com>,
        "wei.huang2@....com" <wei.huang2@....com>
CC:     "kbuild-all@...ts.01.org" <kbuild-all@...ts.01.org>
Subject: 答复: [PATCH] [v4] KVM: X86: support APERF/MPERF registers

> Hi Li,
> 
> Thank you for the patch! Perhaps something to improve:
> 
> [auto build test WARNING on kvm/linux-next] [also build test WARNING on
> next-20200505] [cannot apply to tip/auto-latest linus/master linux/master
> v5.7-rc4] [if your patch is applied to the wrong git tree, please drop us a note to
> help improve the system. BTW, we also suggest to use '--base' option to specify
> the base tree in git format-patch, please see
> https://stackoverflow.com/a/37406982]
> 
> url:
> https://github.com/0day-ci/linux/commits/Li-RongQing/KVM-X86-support-APE
> RF-MPERF-registers/20200507-023327
> base:   https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next
> config: x86_64-allmodconfig (attached as .config)
> compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
> reproduce:
>         # save the attached .config to linux build tree
>         make ARCH=x86_64
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kbuild test robot <lkp@...el.com>
> 
> Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
> http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
> 
> All warnings (new ones prefixed by >>):
> 
>    arch/x86/kvm/x86.c: In function 'vcpu_enter_guest':
> >> arch/x86/kvm/x86.c:8219:13: warning: 'aperf' may be used
> >> uninitialized in this function [-Wmaybe-uninitialized]
>      u64 mperf, aperf;
>                 ^~~~~
> >> arch/x86/kvm/x86.c:8219:6: warning: 'mperf' may be used uninitialized
> >> in this function [-Wmaybe-uninitialized]
>      u64 mperf, aperf;
>          ^~~~~

I think this is a FALSE warning, set and use mperf/aperf only if enable_aperfmperf is true


-Li