Re: [PATCH hyperv-next v6 01/11] arm64: kvm, smccc: Introduce and use API for detecting hypervisor presence

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

Hi Roman,

kernel test robot noticed the following build warnings:

[auto build test WARNING on d9608f6dc3e3229a40e1db1dab573d6882f38c2a]

url:    https://github.com/intel-lab-lkp/linux/commits/Roman-Kisel/arm64-kvm-smccc-Introduce-and-use-API-for-detecting-hypervisor-presence/20250315-082319
base:   d9608f6dc3e3229a40e1db1dab573d6882f38c2a
patch link:    https://lore.kernel.org/r/20250315001931.631210-2-romank%40linux.microsoft.com
patch subject: [PATCH hyperv-next v6 01/11] arm64: kvm, smccc: Introduce and use API for detecting hypervisor presence
config: arm64-randconfig-r122-20250317 (https://download.01.org/0day-ci/archive/20250317/202503172236.TQovQLBw-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 14.2.0
reproduce: (https://download.01.org/0day-ci/archive/20250317/202503172236.TQovQLBw-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/202503172236.TQovQLBw-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> arch/arm64/kvm/hypercalls.c:356:17: sparse: sparse: cast to restricted __le32
>> arch/arm64/kvm/hypercalls.c:356:17: sparse: sparse: cast to restricted __le32
>> arch/arm64/kvm/hypercalls.c:356:17: sparse: sparse: cast to restricted __le32
>> arch/arm64/kvm/hypercalls.c:356:17: sparse: sparse: cast to restricted __le32

vim +356 arch/arm64/kvm/hypercalls.c

   262	
   263	int kvm_smccc_call_handler(struct kvm_vcpu *vcpu)
   264	{
   265		struct kvm_smccc_features *smccc_feat = &vcpu->kvm->arch.smccc_feat;
   266		u32 func_id = smccc_get_function(vcpu);
   267		u64 val[4] = {SMCCC_RET_NOT_SUPPORTED};
   268		u32 feature;
   269		u8 action;
   270		gpa_t gpa;
   271	
   272		action = kvm_smccc_get_action(vcpu, func_id);
   273		switch (action) {
   274		case KVM_SMCCC_FILTER_HANDLE:
   275			break;
   276		case KVM_SMCCC_FILTER_DENY:
   277			goto out;
   278		case KVM_SMCCC_FILTER_FWD_TO_USER:
   279			kvm_prepare_hypercall_exit(vcpu, func_id);
   280			return 0;
   281		default:
   282			WARN_RATELIMIT(1, "Unhandled SMCCC filter action: %d\n", action);
   283			goto out;
   284		}
   285	
   286		switch (func_id) {
   287		case ARM_SMCCC_VERSION_FUNC_ID:
   288			val[0] = ARM_SMCCC_VERSION_1_1;
   289			break;
   290		case ARM_SMCCC_ARCH_FEATURES_FUNC_ID:
   291			feature = smccc_get_arg1(vcpu);
   292			switch (feature) {
   293			case ARM_SMCCC_ARCH_WORKAROUND_1:
   294				switch (arm64_get_spectre_v2_state()) {
   295				case SPECTRE_VULNERABLE:
   296					break;
   297				case SPECTRE_MITIGATED:
   298					val[0] = SMCCC_RET_SUCCESS;
   299					break;
   300				case SPECTRE_UNAFFECTED:
   301					val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
   302					break;
   303				}
   304				break;
   305			case ARM_SMCCC_ARCH_WORKAROUND_2:
   306				switch (arm64_get_spectre_v4_state()) {
   307				case SPECTRE_VULNERABLE:
   308					break;
   309				case SPECTRE_MITIGATED:
   310					/*
   311					 * SSBS everywhere: Indicate no firmware
   312					 * support, as the SSBS support will be
   313					 * indicated to the guest and the default is
   314					 * safe.
   315					 *
   316					 * Otherwise, expose a permanent mitigation
   317					 * to the guest, and hide SSBS so that the
   318					 * guest stays protected.
   319					 */
   320					if (kvm_has_feat(vcpu->kvm, ID_AA64PFR1_EL1, SSBS, IMP))
   321						break;
   322					fallthrough;
   323				case SPECTRE_UNAFFECTED:
   324					val[0] = SMCCC_RET_NOT_REQUIRED;
   325					break;
   326				}
   327				break;
   328			case ARM_SMCCC_ARCH_WORKAROUND_3:
   329				switch (arm64_get_spectre_bhb_state()) {
   330				case SPECTRE_VULNERABLE:
   331					break;
   332				case SPECTRE_MITIGATED:
   333					val[0] = SMCCC_RET_SUCCESS;
   334					break;
   335				case SPECTRE_UNAFFECTED:
   336					val[0] = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
   337					break;
   338				}
   339				break;
   340			case ARM_SMCCC_HV_PV_TIME_FEATURES:
   341				if (test_bit(KVM_REG_ARM_STD_HYP_BIT_PV_TIME,
   342					     &smccc_feat->std_hyp_bmap))
   343					val[0] = SMCCC_RET_SUCCESS;
   344				break;
   345			}
   346			break;
   347		case ARM_SMCCC_HV_PV_TIME_FEATURES:
   348			val[0] = kvm_hypercall_pv_features(vcpu);
   349			break;
   350		case ARM_SMCCC_HV_PV_TIME_ST:
   351			gpa = kvm_init_stolen_time(vcpu);
   352			if (gpa != INVALID_GPA)
   353				val[0] = gpa;
   354			break;
   355		case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
 > 356			UUID_TO_SMCCC_RES(ARM_SMCCC_VENDOR_HYP_UID_KVM, val);
   357			break;
   358		case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
   359			val[0] = smccc_feat->vendor_hyp_bmap;
   360			break;
   361		case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID:
   362			kvm_ptp_get_time(vcpu, val);
   363			break;
   364		case ARM_SMCCC_TRNG_VERSION:
   365		case ARM_SMCCC_TRNG_FEATURES:
   366		case ARM_SMCCC_TRNG_GET_UUID:
   367		case ARM_SMCCC_TRNG_RND32:
   368		case ARM_SMCCC_TRNG_RND64:
   369			return kvm_trng_call(vcpu);
   370		default:
   371			return kvm_psci_call(vcpu);
   372		}
   373	
   374	out:
   375		smccc_set_retval(vcpu, val[0], val[1], val[2], val[3]);
   376		return 1;
   377	}
   378	

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