Re: [PATCH v2] KVM: x86: Unify L1TF flushing under per-CPU variable

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

Hi Brendan,

kernel test robot noticed the following build errors:

[auto build test ERROR on 6b36119b94d0b2bb8cea9d512017efafd461d6ac]

url:    https://github.com/intel-lab-lkp/linux/commits/Brendan-Jackman/KVM-x86-Unify-L1TF-flushing-under-per-CPU-variable/20251016-011539
base:   6b36119b94d0b2bb8cea9d512017efafd461d6ac
patch link:    https://lore.kernel.org/r/20251015-b4-l1tf-percpu-v2-1-6d7a8d3d40e9%40google.com
patch subject: [PATCH v2] KVM: x86: Unify L1TF flushing under per-CPU variable
config: i386-buildonly-randconfig-006-20251016 (https://download.01.org/0day-ci/archive/20251016/202510161649.QbfhDLy3-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251016/202510161649.QbfhDLy3-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/202510161649.QbfhDLy3-lkp@intel.com/

All errors (new ones prefixed by >>):

   arch/x86/kvm/x86.c: In function 'kvm_write_guest_virt_system':
>> arch/x86/kvm/x86.c:8003:9: error: implicit declaration of function 'kvm_set_cpu_l1tf_flush_l1d_raw'; did you mean 'kvm_set_cpu_l1tf_flush_l1d'? [-Wimplicit-function-declaration]
    8003 |         kvm_set_cpu_l1tf_flush_l1d_raw();
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
         |         kvm_set_cpu_l1tf_flush_l1d


vim +8003 arch/x86/kvm/x86.c

  7998	
  7999	int kvm_write_guest_virt_system(struct kvm_vcpu *vcpu, gva_t addr, void *val,
  8000					unsigned int bytes, struct x86_exception *exception)
  8001	{
  8002		/* kvm_write_guest_virt_system can pull in tons of pages. */
> 8003		kvm_set_cpu_l1tf_flush_l1d_raw();
  8004	
  8005		return kvm_write_guest_virt_helper(addr, val, bytes, vcpu,
  8006						   PFERR_WRITE_MASK, exception);
  8007	}
  8008	EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_write_guest_virt_system);
  8009	

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