[android-common:android15-6.6 2/2] arch/arm64/kvm/mmu.c:394: warning: Function parameter or member 'kvm' not described in '___unmap_stage2_range'

[android-common:android15-6.6 2/2] arch/arm64/kvm/mmu.c:394: warning: Function parameter or member 'kvm' not described in '___unmap_stage2_range'

[kernel test robot]

Hi Quentin,

FYI, the error/warning still remains.

tree:   https://android.googlesource.com/kernel/common android15-6.6
head:   5fdbbd61a3cbdca7ac1034dc16723bdbc7ece8cc
commit: b66e27a61e1f4f713201f1cd1d475da9309218ae [2/2] ANDROID: KVM: arm64: Unshare pages from __unmap_stage2_range()
config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20260331/202603311618.n0d8DBCp-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260331/202603311618.n0d8DBCp-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/202603311618.n0d8DBCp-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> arch/arm64/kvm/mmu.c:394: warning: Function parameter or member 'kvm' not described in '___unmap_stage2_range'
>> arch/arm64/kvm/mmu.c:394: warning: Function parameter or member 'addr' not described in '___unmap_stage2_range'
>> arch/arm64/kvm/mmu.c:394: warning: expecting prototype for unmap_stage2_range(). Prototype was for ___unmap_stage2_range() instead


vim +394 arch/arm64/kvm/mmu.c

b66e27a61e1f4f arch/arm64/kvm/mmu.c Quentin Perret   2022-07-06  355  
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  356  /*
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  357   * Unmapping vs dcache management:
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  358   *
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  359   * If a guest maps certain memory pages as uncached, all writes will
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  360   * bypass the data cache and go directly to RAM.  However, the CPUs
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  361   * can still speculate reads (not writes) and fill cache lines with
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  362   * data.
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  363   *
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  364   * Those cache lines will be *clean* cache lines though, so a
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  365   * clean+invalidate operation is equivalent to an invalidate
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  366   * operation, because no cache lines are marked dirty.
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  367   *
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  368   * Those clean cache lines could be filled prior to an uncached write
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  369   * by the guest, and the cache coherent IO subsystem would therefore
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  370   * end up writing old data to disk.
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  371   *
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  372   * This is why right after unmapping a page/section and invalidating
52bae936f0e7be arch/arm64/kvm/mmu.c Will Deacon      2020-09-11  373   * the corresponding TLBs, we flush to make sure the IO subsystem will
52bae936f0e7be arch/arm64/kvm/mmu.c Will Deacon      2020-09-11  374   * never hit in the cache.
e48d53a91f6e90 virt/kvm/arm/mmu.c   Marc Zyngier     2018-04-06  375   *
e48d53a91f6e90 virt/kvm/arm/mmu.c   Marc Zyngier     2018-04-06  376   * This is all avoided on systems that have ARM64_HAS_STAGE2_FWB, as
e48d53a91f6e90 virt/kvm/arm/mmu.c   Marc Zyngier     2018-04-06  377   * we then fully enforce cacheability of RAM, no matter what the guest
e48d53a91f6e90 virt/kvm/arm/mmu.c   Marc Zyngier     2018-04-06  378   * does.
363ef89f8e9bce arch/arm/kvm/mmu.c   Marc Zyngier     2014-12-19  379   */
7a1c831ee8553b arch/arm/kvm/mmu.c   Suzuki K Poulose 2016-03-23  380  /**
7a1c831ee8553b arch/arm/kvm/mmu.c   Suzuki K Poulose 2016-03-23  381   * unmap_stage2_range -- Clear stage2 page table entries to unmap a range
c9c0279cc02b4e arch/arm64/kvm/mmu.c Xiaofei Tan      2020-09-17  382   * @mmu:   The KVM stage-2 MMU pointer
7a1c831ee8553b arch/arm/kvm/mmu.c   Suzuki K Poulose 2016-03-23  383   * @start: The intermediate physical base address of the range to unmap
7a1c831ee8553b arch/arm/kvm/mmu.c   Suzuki K Poulose 2016-03-23  384   * @size:  The size of the area to unmap
c9c0279cc02b4e arch/arm64/kvm/mmu.c Xiaofei Tan      2020-09-17  385   * @may_block: Whether or not we are permitted to block
7a1c831ee8553b arch/arm/kvm/mmu.c   Suzuki K Poulose 2016-03-23  386   *
7a1c831ee8553b arch/arm/kvm/mmu.c   Suzuki K Poulose 2016-03-23  387   * Clear a range of stage-2 mappings, lowering the various ref-counts.  Must
7a1c831ee8553b arch/arm/kvm/mmu.c   Suzuki K Poulose 2016-03-23  388   * be called while holding mmu_lock (unless for freeing the stage2 pgd before
7a1c831ee8553b arch/arm/kvm/mmu.c   Suzuki K Poulose 2016-03-23  389   * destroying the VM), otherwise another faulting VCPU may come in and mess
7a1c831ee8553b arch/arm/kvm/mmu.c   Suzuki K Poulose 2016-03-23  390   * with things behind our backs.
7a1c831ee8553b arch/arm/kvm/mmu.c   Suzuki K Poulose 2016-03-23  391   */
776adf654a1f64 arch/arm64/kvm/mmu.c Quentin Perret   2022-05-11  392  
776adf654a1f64 arch/arm64/kvm/mmu.c Quentin Perret   2022-05-11  393  static int ___unmap_stage2_range(struct kvm *kvm, u64 addr, u64 size)
776adf654a1f64 arch/arm64/kvm/mmu.c Quentin Perret   2022-05-11 @394  {
b66e27a61e1f4f arch/arm64/kvm/mmu.c Quentin Perret   2022-07-06  395  	if (!is_protected_kvm_enabled())
776adf654a1f64 arch/arm64/kvm/mmu.c Quentin Perret   2022-05-11  396  		return kvm_pgtable_stage2_unmap(kvm->arch.mmu.pgt, addr, size);
b66e27a61e1f4f arch/arm64/kvm/mmu.c Quentin Perret   2022-07-06  397  
b66e27a61e1f4f arch/arm64/kvm/mmu.c Quentin Perret   2022-07-06  398  	return pkvm_unmap_range(kvm, addr, addr + size);
776adf654a1f64 arch/arm64/kvm/mmu.c Quentin Perret   2022-05-11  399  }
776adf654a1f64 arch/arm64/kvm/mmu.c Quentin Perret   2022-05-11  400  

:::::: The code at line 394 was first introduced by commit
:::::: 776adf654a1f64054a76876923c1606224e431cc ANDROID: KVM: arm64: Pass kvm struct to stage2_apply_range()

:::::: TO: Quentin Perret <qperret@google.com>
:::::: CC: Quentin Perret <qperret@google.com>

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https://github.com/intel/lkp-tests/wiki