Re: [RFC PATCH v2 01/10] kvm: gmem: Add option to remove gmem from direct map

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

Hi Patrick,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build errors:

[auto build test ERROR on 332d2c1d713e232e163386c35a3ba0c1b90df83f]

url:    https://github.com/intel-lab-lkp/linux/commits/Patrick-Roy/kvm-gmem-Add-option-to-remove-gmem-from-direct-map/20240911-003258
base:   332d2c1d713e232e163386c35a3ba0c1b90df83f
patch link:    https://lore.kernel.org/r/20240910163038.1298452-2-roypat%40amazon.co.uk
patch subject: [RFC PATCH v2 01/10] kvm: gmem: Add option to remove gmem from direct map
config: x86_64-rhel-8.3-rust (https://download.01.org/0day-ci/archive/20240914/202409140159.nGVKH1ST-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240914/202409140159.nGVKH1ST-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/202409140159.nGVKH1ST-lkp@intel.com/

All errors (new ones prefixed by >>):

>> arch/x86/kvm/../../../virt/kvm/guest_memfd.c:71:2: error: call to undeclared function 'flush_tlb_kernel_range'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
      71 |         flush_tlb_kernel_range(start, start + folio_size(folio));
         |         ^
   1 error generated.


vim +/flush_tlb_kernel_range +71 arch/x86/kvm/../../../virt/kvm/guest_memfd.c

    57	
    58	static int kvm_gmem_folio_set_private(struct folio *folio)
    59	{
    60		unsigned long start, npages, i;
    61		int r;
    62	
    63		start = (unsigned long) folio_address(folio);
    64		npages = folio_nr_pages(folio);
    65	
    66		for (i = 0; i < npages; ++i) {
    67			r = set_direct_map_invalid_noflush(folio_page(folio, i));
    68			if (r)
    69				goto out_remap;
    70		}
  > 71		flush_tlb_kernel_range(start, start + folio_size(folio));
    72		folio_set_private(folio);
    73		return 0;
    74	out_remap:
    75		for (; i > 0; i--) {
    76			struct page *page = folio_page(folio, i - 1);
    77	
    78			if (WARN_ON_ONCE(set_direct_map_default_noflush(page))) {
    79				/*
    80				 * Random holes in the direct map are bad, let's mark
    81				 * these pages as corrupted memory so that the kernel
    82				 * avoids ever touching them again.
    83				 */
    84				folio_set_hwpoison(folio);
    85				r = -EHWPOISON;
    86			}
    87		}
    88		return r;
    89	}
    90	

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