[PATCH v4 4/4] x86/snp: Convert shared memory back to private on kexec

[kernel test robot]

Hi Ashish,

kernel test robot noticed the following build errors:

[auto build test ERROR on tip/master]
[also build test ERROR on linus/master next-20240410]
[cannot apply to tip/x86/core tip/x86/mm tip/auto-latest]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ashish-Kalra/efi-x86-skip-efi_arch_mem_reserve-in-case-of-kexec/20240410-044512
base:   tip/master
patch link:    https://lore.kernel.org/r/b24885f5495f6b8ba2f9e825fda9188fcbf28231.1712694667.git.ashish.kalra%40amd.com
patch subject: [PATCH v4 4/4] x86/snp: Convert shared memory back to private on kexec
config: x86_64-rhel-8.3-rust (https://download.01.org/0day-ci/archive/20240410/202404102232.UKwWHSTE-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240410/202404102232.UKwWHSTE-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202404102232.UKwWHSTE-lkp@intel.com/

All errors (new ones prefixed by >>):

>> arch/x86/kernel/sev.c:993:14: error: call to undeclared function 'pte_decrypted'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     993 |                 if (pte && pte_decrypted(*pte) && !pte_none(*pte)) {
         |                            ^
   arch/x86/kernel/sev.c:1021:16: error: call to undeclared function 'pte_decrypted'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1021 |                 if (!pte || !pte_decrypted(*pte) || pte_none(*pte))
         |                              ^
>> arch/x86/kernel/sev.c:1041:7: error: call to undeclared function 'stop_memory_enc_conversion'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1041 |         if (!stop_memory_enc_conversion(wait_for_lock))
         |              ^
   3 errors generated.
--
>> arch/x86/mm/mem_encrypt_amd.c:471:21: error: no member named 'enc_kexec_stop_conversion' in 'struct x86_guest'
     471 |         x86_platform.guest.enc_kexec_stop_conversion = snp_kexec_stop_conversion;
         |         ~~~~~~~~~~~~~~~~~~ ^
>> arch/x86/mm/mem_encrypt_amd.c:472:21: error: no member named 'enc_kexec_unshare_mem' in 'struct x86_guest'
     472 |         x86_platform.guest.enc_kexec_unshare_mem     = snp_kexec_unshare_mem;
         |         ~~~~~~~~~~~~~~~~~~ ^
   2 errors generated.


vim +/pte_decrypted +993 arch/x86/kernel/sev.c

   970	
   971	static void unshare_all_memory(void)
   972	{
   973		unsigned long addr, end;
   974	
   975		/*
   976		 * Walk direct mapping and convert all shared memory back to private,
   977		 */
   978	
   979		addr = PAGE_OFFSET;
   980		end  = PAGE_OFFSET + get_max_mapped();
   981	
   982		while (addr < end) {
   983			unsigned long size;
   984			unsigned int level;
   985			pte_t *pte;
   986	
   987			pte = lookup_address(addr, &level);
   988			size = page_level_size(level);
   989	
   990			/*
   991			 * pte_none() check is required to skip physical memory holes in direct mapped.
   992			 */
 > 993			if (pte && pte_decrypted(*pte) && !pte_none(*pte)) {
   994				int pages = size / PAGE_SIZE;
   995	
   996				if (!make_pte_private(pte, addr, pages, level)) {
   997					pr_err("Failed to unshare range %#lx-%#lx\n",
   998					       addr, addr + size);
   999				}
  1000	
  1001			}
  1002	
  1003			addr += size;
  1004		}
  1005		__flush_tlb_all();
  1006	
  1007	}
  1008	
  1009	static void unshare_all_bss_decrypted_memory(void)
  1010	{
  1011		unsigned long vaddr, vaddr_end;
  1012		unsigned int level;
  1013		unsigned int npages;
  1014		pte_t *pte;
  1015	
  1016		vaddr = (unsigned long)__start_bss_decrypted;
  1017		vaddr_end = (unsigned long)__start_bss_decrypted_unused;
  1018		npages = (vaddr_end - vaddr) >> PAGE_SHIFT;
  1019		for (; vaddr < vaddr_end; vaddr += PAGE_SIZE) {
  1020			pte = lookup_address(vaddr, &level);
  1021			if (!pte || !pte_decrypted(*pte) || pte_none(*pte))
  1022				continue;
  1023	
  1024			set_pte_enc(pte, level, (void *)vaddr);
  1025		}
  1026		vaddr = (unsigned long)__start_bss_decrypted;
  1027		snp_set_memory_private(vaddr, npages);
  1028	}
  1029	
  1030	/* Stop new private<->shared conversions */
  1031	void snp_kexec_stop_conversion(bool crash)
  1032	{
  1033		/*
  1034		 * Crash kernel reaches here with interrupts disabled: can't wait for
  1035		 * conversions to finish.
  1036		 *
  1037		 * If race happened, just report and proceed.
  1038		 */
  1039		bool wait_for_lock = !crash;
  1040	
> 1041		if (!stop_memory_enc_conversion(wait_for_lock))
  1042			pr_warn("Failed to finish shared<->private conversions\n");
  1043	}
  1044	

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