KVM: X86: Do the same ignore_msrs check for feature msrs

Logically the ignore_msrs and report_ignored_msrs should also apply to feature
MSRs.  Add them in.

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20200622220442.21998-3-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm/svm.c

@@ -2359,7 +2359,7 @@ static int svm_get_msr_feature(struct kvm_msr_entry *msr)
 			msr->data |= MSR_F10H_DECFG_LFENCE_SERIALIZE;
 		break;
 	default:
-		return 1;
+		return KVM_MSR_RET_INVALID;
 	}
 
 	return 0;

arch/x86/kvm/vmx/vmx.c

@@ -1815,7 +1815,7 @@ static int vmx_get_msr_feature(struct kvm_msr_entry *msr)
 		msr->data = vmx_get_perf_capabilities();
 		return 0;
 	default:
-		return 1;
+		return KVM_MSR_RET_INVALID;
 	}
 }
 

arch/x86/kvm/x86.c

@@ -1412,8 +1412,7 @@ static int kvm_get_msr_feature(struct kvm_msr_entry *msr)
 		rdmsrl_safe(msr->index, &msr->data);
 		break;
 	default:
-		if (kvm_x86_ops.get_msr_feature(msr))
-			return 1;
+		return kvm_x86_ops.get_msr_feature(msr);
 	}
 	return 0;
 }
@@ -1425,6 +1424,13 @@ static int do_get_msr_feature(struct kvm_vcpu *vcpu, unsigned index, u64 *data)
 
 	msr.index = index;
 	r = kvm_get_msr_feature(&msr);
+
+	if (r == KVM_MSR_RET_INVALID) {
+		/* Unconditionally clear the output for simplicity */
+		*data = 0;
+		r = kvm_msr_ignored_check(vcpu, index, 0, false);
+	}
+
 	if (r)
 		return r;