[anolis-intel-cloud:devel-6.6 0/94] arch/x86/kvm/svm/csv.c:774:6: warning: variable 'pfn' is used uninitialized whenever 'if' condition is true

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

tree:   https://gitee.com/anolis/intel-cloud-kernel.git devel-6.6
head:   a79e0786f3fa90fd521f198ac6ccf6b11dbf67c2
commit: c0bfce1e4fad37d7dd413e3ef813e18edd738d4f [0/94] anolis: KVM: SVM: CSV: Manage CSV3 guest's nested page table
config: x86_64-rhel-9.4-rust (https://download.01.org/0day-ci/archive/20250510/202505101324.MRXaYYFi-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
rustc: rustc 1.73.0 (cc66ad468 2023-10-03)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250510/202505101324.MRXaYYFi-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/202505101324.MRXaYYFi-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/x86/kvm/svm/csv.c:774:6: warning: variable 'pfn' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
     774 |         if (error_code & PFERR_PRESENT_MASK)
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/x86/kvm/svm/csv.c:787:15: note: uninitialized use occurs here
     787 |                                 &psp_ret, pfn, level);
         |                                           ^~~
   arch/x86/kvm/svm/csv.c:774:2: note: remove the 'if' if its condition is always false
     774 |         if (error_code & PFERR_PRESENT_MASK)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     775 |                 level = CSV3_PG_LEVEL_4K;
         |                 ~~~~~~~~~~~~~~~~~~~~~~~~~
     776 |         else {
         |         ~~~~
   arch/x86/kvm/svm/csv.c:771:15: note: initialize the variable 'pfn' to silence this warning
     771 |         kvm_pfn_t pfn;
         |                      ^
         |                       = 0
   1 warning generated.


vim +774 arch/x86/kvm/svm/csv.c

   764	
   765	static int csv3_page_fault(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot,
   766				   gfn_t gfn, u32 error_code)
   767	{
   768		int ret = 0;
   769		int psp_ret = 0;
   770		int level;
   771		kvm_pfn_t pfn;
   772		struct kvm_csv_info *csv = &to_kvm_svm_csv(vcpu->kvm)->csv_info;
   773	
 > 774		if (error_code & PFERR_PRESENT_MASK)
   775			level = CSV3_PG_LEVEL_4K;
   776		else {
   777			mutex_lock(&csv->shared_page_block_lock);
   778			ret = csv3_pin_shared_memory(vcpu, slot, gfn, &pfn);
   779			mutex_unlock(&csv->shared_page_block_lock);
   780			if (ret)
   781				goto exit;
   782	
   783			level = csv3_mapping_level(vcpu, gfn, pfn, slot);
   784		}
   785	
   786		ret = __csv3_page_fault(vcpu, gfn << PAGE_SHIFT, error_code, slot,
   787					&psp_ret, pfn, level);
   788	
   789		if (psp_ret != SEV_RET_SUCCESS)
   790			ret = -EFAULT;
   791	exit:
   792		return ret;
   793	}
   794	

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