linux-kernel - Re: [PATCH] KVM: VMX: Use try_cmpxchg64 in pi_try_set

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Date:   Thu, 19 May 2022 10:42:17 +0800
From:   kernel test robot <lkp@...el.com>
To:     Uros Bizjak <ubizjak@...il.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     llvm@...ts.linux.dev, kbuild-all@...ts.01.org,
        Uros Bizjak <ubizjak@...il.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>
Subject: Re: [PATCH] KVM: VMX: Use try_cmpxchg64 in pi_try_set_control

Hi Uros,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on kvm/master]
[also build test ERROR on mst-vhost/linux-next linux/master linus/master v5.18-rc7 next-20220518]
[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]

url:    https://github.com/intel-lab-lkp/linux/commits/Uros-Bizjak/KVM-VMX-Use-try_cmpxchg64-in-pi_try_set_control/20220518-214709
base:   https://git.kernel.org/pub/scm/virt/kvm/kvm.git master
config: i386-randconfig-a002 (https://download.01.org/0day-ci/archive/20220519/202205191028.PcCtw7Xz-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 853fa8ee225edf2d0de94b0dcbd31bea916e825e)
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/2af4f7c4ecfcaedf9b98ba30ee508dc0d9002955
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Uros-Bizjak/KVM-VMX-Use-try_cmpxchg64-in-pi_try_set_control/20220518-214709
        git checkout 2af4f7c4ecfcaedf9b98ba30ee508dc0d9002955
        # 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=i386 SHELL=/bin/bash arch/x86/kvm/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>

All errors (new ones prefixed by >>):

>> arch/x86/kvm/vmx/posted_intr.c:45:7: error: call to undeclared function 'try_cmpxchg64'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
           if (!try_cmpxchg64(&pi_desc->control, pold, new))
                ^
   arch/x86/kvm/vmx/posted_intr.c:45:7: note: did you mean '__cmpxchg64'?
   arch/x86/include/asm/cmpxchg_32.h:47:19: note: '__cmpxchg64' declared here
   static inline u64 __cmpxchg64(volatile u64 *ptr, u64 old, u64 new)
                     ^
   1 error generated.


vim +/try_cmpxchg64 +45 arch/x86/kvm/vmx/posted_intr.c

    36	
    37	static int pi_try_set_control(struct pi_desc *pi_desc, u64 *pold, u64 new)
    38	{
    39		/*
    40		 * PID.ON can be set at any time by a different vCPU or by hardware,
    41		 * e.g. a device.  PID.control must be written atomically, and the
    42		 * update must be retried with a fresh snapshot an ON change causes
    43		 * the cmpxchg to fail.
    44		 */
  > 45		if (!try_cmpxchg64(&pi_desc->control, pold, new))
    46			return -EBUSY;
    47	
    48		return 0;
    49	}
    50	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp