Re: [PATCH v2] x86: disable PKU when running on Apple Virtualization

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

Hi Akihiro,

kernel test robot noticed the following build errors:

[auto build test ERROR on tip/x86/core]
[also build test ERROR on tip/master linus/master v6.14-rc6 next-20250313]
[cannot apply to 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/Akihiro-Suda/x86-disable-PKU-when-running-on-Apple-Virtualization/20250312-181106
base:   tip/x86/core
patch link:    https://lore.kernel.org/r/20250312100926.34954-1-akihiro.suda.cz%40hco.ntt.co.jp
patch subject: [PATCH v2] x86: disable PKU when running on Apple Virtualization
config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20250314/202503141349.bpi8pvc4-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/20250314/202503141349.bpi8pvc4-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/202503141349.bpi8pvc4-lkp@intel.com/

All errors (new ones prefixed by >>):

>> arch/x86/kernel/cpu/common.c:530:14: error: use of undeclared identifier 'acpi_gbl_FADT'
     530 |         if (!memcmp(acpi_gbl_FADT.header.oem_table_id, "Apple Vz", 8)) {
         |                     ^
   1 error generated.


vim +/acpi_gbl_FADT +530 arch/x86/kernel/cpu/common.c

   517	
   518	static __always_inline void setup_pku(struct cpuinfo_x86 *c)
   519	{
   520		/*
   521		 * OSPKE seems broken on Apple Virtualization.
   522		 * https://lore.kernel.org/regressions/CAG8fp8QvH71Wi_y7b7tgFp7knK38rfrF7rRHh-gFKqeS0gxY6Q@mail.gmail.com/T/#u
   523		 *
   524		 * TODO: conditionally enable pku depending on the DMI BIOS version when Apple
   525		 * fixes the issue.
   526		 *
   527		 * However, this would be still not enough because DMI is missing when vmlinuz
   528		 * is directly loaded into VM.
   529		 */
 > 530		if (!memcmp(acpi_gbl_FADT.header.oem_table_id, "Apple Vz", 8)) {
   531			pr_info("pku: disabled on Apple Virtualization platform (Intel) due to a bug\n");
   532			pku_disabled = true;
   533		}
   534	
   535		if (c == &boot_cpu_data) {
   536			if (pku_disabled || !cpu_feature_enabled(X86_FEATURE_PKU))
   537				return;
   538			/*
   539			 * Setting CR4.PKE will cause the X86_FEATURE_OSPKE cpuid
   540			 * bit to be set.  Enforce it.
   541			 */
   542			setup_force_cpu_cap(X86_FEATURE_OSPKE);
   543	
   544		} else if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) {
   545			return;
   546		}
   547	
   548		cr4_set_bits(X86_CR4_PKE);
   549		/* Load the default PKRU value */
   550		pkru_write_default();
   551	}
   552	

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