s390/kvm: remove explicit -EFAULT return code checking on guest access

Let's change to the paradigm that every return code from guest memory
access functions that is not zero translates to -EFAULT and do not
explictly compare.
Explictly comparing the return value with -EFAULT has already shown to
be a bit fragile. In addition this is closer to the handling of
copy_to/from_user functions, which imho is in general a good idea.

Also shorten the return code handling in interrupt.c a bit.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/s390/kvm/intercept.c

@@ -45,7 +45,7 @@ static int handle_lctlg(struct kvm_vcpu *vcpu)
 	do {
 		rc = get_guest_u64(vcpu, useraddr,
 				   &vcpu->arch.sie_block->gcr[reg]);
-		if (rc == -EFAULT) {
+		if (rc) {
 			kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 			break;
 		}
@@ -79,7 +79,7 @@ static int handle_lctl(struct kvm_vcpu *vcpu)
 	reg = reg1;
 	do {
 		rc = get_guest_u32(vcpu, useraddr, &val);
-		if (rc == -EFAULT) {
+		if (rc) {
 			kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 			break;
 		}

arch/s390/kvm/priv.c

@@ -108,7 +108,7 @@ static int handle_store_cpu_address(struct kvm_vcpu *vcpu)
 	}
 
 	rc = put_guest_u16(vcpu, useraddr, vcpu->vcpu_id);
-	if (rc == -EFAULT) {
+	if (rc) {
 		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 		goto out;
 	}
@@ -230,7 +230,7 @@ static int handle_stfl(struct kvm_vcpu *vcpu)
 
 	rc = copy_to_guest(vcpu, offsetof(struct _lowcore, stfl_fac_list),
 			   &facility_list, sizeof(facility_list));
-	if (rc == -EFAULT)
+	if (rc)
 		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 	else {
 		VCPU_EVENT(vcpu, 5, "store facility list value %x",
@@ -348,7 +348,7 @@ static int handle_stidp(struct kvm_vcpu *vcpu)
 	}
 
 	rc = put_guest_u64(vcpu, operand2, vcpu->arch.stidp_data);
-	if (rc == -EFAULT) {
+	if (rc) {
 		kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
 		goto out;
 	}