KVM: x86/cpuid: Exclude unpermitted xfeatures sizes at KVM_GET_SUPPOR…

…TED_CPUID

With the help of xstate_get_guest_group_perm(), KVM can exclude unpermitted
xfeatures in cpuid.0xd.0.eax, in which case the corresponding xfeatures
sizes should also be matched to the permitted xfeatures.

Fixing this inconsistency by introducing a local variable with the same
name also helps to fix cpuid.0xd.1.ebx and later leaf-by-leaf queries.

Fixes: 445ecdf ("kvm: x86: Exclude unpermitted xfeatures at KVM_GET_SUPPORTED_CPUID")
Signed-off-by: Like Xu <likexu@tencent.com>

arch/x86/kvm/cpuid.c

@@ -887,12 +887,12 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 		}
 		break;
 	case 0xd: {
-		u64 guest_perm = xstate_get_guest_group_perm();
+		u64 supported_xcr0 = supported_xcr0 & xstate_get_guest_group_perm();
 
-		entry->eax &= supported_xcr0 & guest_perm;
+		entry->eax &= supported_xcr0;
 		entry->ebx = xstate_required_size(supported_xcr0, false);
 		entry->ecx = entry->ebx;
-		entry->edx &= (supported_xcr0 & guest_perm) >> 32;
+		entry->edx &= supported_xcr0 >> 32;
 		if (!supported_xcr0)
 			break;