[linux-next:master 11576/12208] arch/x86/kernel/cpu/mshyperv.c:407: undefined reference to `isolation_type_en_snp'

[linux-next:master 11576/12208] arch/x86/kernel/cpu/mshyperv.c:407: undefined reference to `isolation_type_en_snp'

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   e3f80d3eae76c3557b3c9b5938ad01c0e6cf25ec
commit: d6e2d652443751e290b2edb70173ec3c22f78fbe [11576/12208] x86/hyperv: Add sev-snp enlightened guest static key
config: x86_64-randconfig-103-20230823 (https://download.01.org/0day-ci/archive/20230823/202308231805.RyYOycAU-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce: (https://download.01.org/0day-ci/archive/20230823/202308231805.RyYOycAU-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/202308231805.RyYOycAU-lkp@intel.com/

All errors (new ones prefixed by >>):

   ld: vmlinux.o: in function `ms_hyperv_init_platform':
>> arch/x86/kernel/cpu/mshyperv.c:407: undefined reference to `isolation_type_en_snp'


vim +407 arch/x86/kernel/cpu/mshyperv.c

   327	
   328		/*
   329		 * Extract the features and hints
   330		 */
   331		ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
   332		ms_hyperv.priv_high = cpuid_ebx(HYPERV_CPUID_FEATURES);
   333		ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
   334		ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
   335	
   336		hv_max_functions_eax = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS);
   337	
   338		pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n",
   339			ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,
   340			ms_hyperv.misc_features);
   341	
   342		ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);
   343		ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS);
   344	
   345		pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
   346			 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
   347	
   348		/*
   349		 * Check CPU management privilege.
   350		 *
   351		 * To mirror what Windows does we should extract CPU management
   352		 * features and use the ReservedIdentityBit to detect if Linux is the
   353		 * root partition. But that requires negotiating CPU management
   354		 * interface (a process to be finalized). For now, use the privilege
   355		 * flag as the indicator for running as root.
   356		 *
   357		 * Hyper-V should never specify running as root and as a Confidential
   358		 * VM. But to protect against a compromised/malicious Hyper-V trying
   359		 * to exploit root behavior to expose Confidential VM memory, ignore
   360		 * the root partition setting if also a Confidential VM.
   361		 */
   362		if ((ms_hyperv.priv_high & HV_CPU_MANAGEMENT) &&
   363		    !(ms_hyperv.priv_high & HV_ISOLATION)) {
   364			hv_root_partition = true;
   365			pr_info("Hyper-V: running as root partition\n");
   366		}
   367	
   368		if (ms_hyperv.hints & HV_X64_HYPERV_NESTED) {
   369			hv_nested = true;
   370			pr_info("Hyper-V: running on a nested hypervisor\n");
   371		}
   372	
   373		/*
   374		 * Extract host information.
   375		 */
   376		if (hv_max_functions_eax >= HYPERV_CPUID_VERSION) {
   377			hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);
   378			hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);
   379			hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);
   380			hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION);
   381	
   382			pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n",
   383				hv_host_info_ebx >> 16, hv_host_info_ebx & 0xFFFF,
   384				hv_host_info_eax, hv_host_info_edx & 0xFFFFFF,
   385				hv_host_info_ecx, hv_host_info_edx >> 24);
   386		}
   387	
   388		if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
   389		    ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
   390			x86_platform.calibrate_tsc = hv_get_tsc_khz;
   391			x86_platform.calibrate_cpu = hv_get_tsc_khz;
   392		}
   393	
   394		if (ms_hyperv.priv_high & HV_ISOLATION) {
   395			ms_hyperv.isolation_config_a = cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG);
   396			ms_hyperv.isolation_config_b = cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG);
   397	
   398			if (ms_hyperv.shared_gpa_boundary_active)
   399				ms_hyperv.shared_gpa_boundary =
   400					BIT_ULL(ms_hyperv.shared_gpa_boundary_bits);
   401	
   402			pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
   403				ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
   404	
   405	
   406			if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) {
 > 407				static_branch_enable(&isolation_type_en_snp);
   408			} else if (hv_get_isolation_type() == HV_ISOLATION_TYPE_SNP) {
   409				static_branch_enable(&isolation_type_snp);
   410			}
   411		}
   412	
   413		if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) {
   414			ms_hyperv.nested_features =
   415				cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
   416			pr_info("Hyper-V: Nested features: 0x%x\n",
   417				ms_hyperv.nested_features);
   418		}
   419	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

RE: [linux-next:master 11576/12208] arch/x86/kernel/cpu/mshyperv.c:407: undefined reference to `isolation_type_en_snp'

[Dexuan Cui]

> From: kernel test robot <lkp@intel.com>
> Sent: Wednesday, August 23, 2023 4:03 AM
> To: Tianyu Lan <Tianyu.Lan@microsoft.com>
> Cc: oe-kbuild-all@lists.linux.dev; Linux Memory Management List <linux-
> mm@kvack.org>; Wei Liu <wei.liu@kernel.org>; Dexuan Cui
> <decui@microsoft.com>; Michael Kelley (LINUX) <mikelley@microsoft.com>
> Subject: [linux-next:master 11576/12208]
> arch/x86/kernel/cpu/mshyperv.c:407: undefined reference to
> `isolation_type_en_snp'

The failure happens because we have CONFIG_HYPERVISOR_GUEST=y, but
CONFIG_HYPERV is not set. This has been fixed in the hyperv-next branch:

https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/log/?h=hyperv-next
https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/commit/?h=hyperv-next&id=86e619c922e616d8780833562a14a5bda329f0c3

The fix is not in linux-next's master branch (currently it's next-20230823) yet.
I believe tomorrow's linux-next would build successfully.

Thanks,
Dexuan