Re: [PATCH] vmx/nested: Set the SGX feature flag only when hardware supported.

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

Hi,

kernel test robot noticed the following build warnings:

[auto build test WARNING on kvm/queue]
[also build test WARNING on kvm/next linus/master v7.0-rc5 next-20260327]
[cannot apply to kvm/linux-next]
[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/18341265598-163-com/vmx-nested-Set-the-SGX-feature-flag-only-when-hardware-supported/20260329-093645
base:   https://git.kernel.org/pub/scm/virt/kvm/kvm.git queue
patch link:    https://lore.kernel.org/r/1774322860-25106-1-git-send-email-18341265598%40163.com
patch subject: [PATCH] vmx/nested: Set the SGX feature flag only when hardware supported.
config: i386-randconfig-012-20260329 (https://download.01.org/0day-ci/archive/20260329/202603291639.FHVs3bEt-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.4.0-5) 12.4.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260329/202603291639.FHVs3bEt-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/202603291639.FHVs3bEt-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from arch/x86/kvm/vmx/hyperv.h:7,
                    from arch/x86/kvm/vmx/nested.h:6,
                    from arch/x86/kvm/vmx/pmu_intel.c:21:
>> arch/x86/kvm/vmx/vmx.h:347:13: warning: 'cpu_has_sgx' defined but not used [-Wunused-function]
     347 | static bool cpu_has_sgx(void)
         |             ^~~~~~~~~~~


vim +/cpu_has_sgx +347 arch/x86/kvm/vmx/vmx.h

   340	
   341	/*
   342	 * There is no X86_FEATURE for SGX yet, but anyway we need to query CPUID
   343	 * directly instead of going through cpu_has(), to ensure KVM is trapping
   344	 * ENCLS whenever it's supported in hardware.  It does not matter whether
   345	 * the host OS supports or has enabled SGX.
   346	 */
 > 347	static bool cpu_has_sgx(void)
   348	{
   349		return cpuid_eax(0) >= 0x12 && (cpuid_eax(0x12) & BIT(0));
   350	}
   351	

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