Re: [PATCH v2] KVM: VMX: Use try_cmpxchg64 in pi_try_set_control

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

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]
[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/20220520-223925
base:   https://git.kernel.org/pub/scm/virt/kvm/kvm.git master
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20220521/202205211837.X2KKIXbP-lkp@intel.com/config)
compiler: gcc-11 (Debian 11.3.0-1) 11.3.0
reproduce (this is a W=1 build):
        # https://github.com/intel-lab-lkp/linux/commit/84128ccce45cc3ece9b9f8d4df8afa81651547c9
        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/20220520-223925
        git checkout 84128ccce45cc3ece9b9f8d4df8afa81651547c9
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash

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 >>):

   arch/x86/kvm/vmx/posted_intr.c: In function 'pi_try_set_control':
>> arch/x86/kvm/vmx/posted_intr.c:45:14: error: implicit declaration of function 'try_cmpxchg64'; did you mean 'try_cmpxchg'? [-Werror=implicit-function-declaration]
      45 |         if (!try_cmpxchg64(&pi_desc->control, &old, new))
         |              ^~~~~~~~~~~~~
         |              try_cmpxchg
   cc1: some warnings being treated as errors


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

    36	
    37	static int pi_try_set_control(struct pi_desc *pi_desc, u64 old, 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, &old, new))
    46			return -EBUSY;
    47	
    48		return 0;
    49	}
    50	

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