KVM: s390: split kvm_s390_logical_to_effective

Split kvm_s390_logical_to_effective to a generic function called
_kvm_s390_logical_to_effective. The new function takes a PSW and an address
and returns the address with the appropriate bits masked off. The old
function now calls the new function with the appropriate PSW from the vCPU.

This is needed to avoid code duplication for vSIE.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org # for VSIE: correctly handle MVPG when in VSIE
Link: https://lore.kernel.org/r/20210302174443.514363-2-imbrenda@linux.ibm.comSigned-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

arch/s390/kvm/gaccess.h

@@ -36,6 +36,29 @@ static inline unsigned long kvm_s390_real_to_abs(struct kvm_vcpu *vcpu,
 	return gra;
 }
 
+/**
+ * _kvm_s390_logical_to_effective - convert guest logical to effective address
+ * @psw: psw of the guest
+ * @ga: guest logical address
+ *
+ * Convert a guest logical address to an effective address by applying the
+ * rules of the addressing mode defined by bits 31 and 32 of the given PSW
+ * (extendended/basic addressing mode).
+ *
+ * Depending on the addressing mode, the upper 40 bits (24 bit addressing
+ * mode), 33 bits (31 bit addressing mode) or no bits (64 bit addressing
+ * mode) of @ga will be zeroed and the remaining bits will be returned.
+ */
+static inline unsigned long _kvm_s390_logical_to_effective(psw_t *psw,
+							   unsigned long ga)
+{
+	if (psw_bits(*psw).eaba == PSW_BITS_AMODE_64BIT)
+		return ga;
+	if (psw_bits(*psw).eaba == PSW_BITS_AMODE_31BIT)
+		return ga & ((1UL << 31) - 1);
+	return ga & ((1UL << 24) - 1);
+}
+
 /**
  * kvm_s390_logical_to_effective - convert guest logical to effective address
  * @vcpu: guest virtual cpu
@@ -52,13 +75,7 @@ static inline unsigned long kvm_s390_real_to_abs(struct kvm_vcpu *vcpu,
 static inline unsigned long kvm_s390_logical_to_effective(struct kvm_vcpu *vcpu,
 							  unsigned long ga)
 {
-	psw_t *psw = &vcpu->arch.sie_block->gpsw;
-
-	if (psw_bits(*psw).eaba == PSW_BITS_AMODE_64BIT)
-		return ga;
-	if (psw_bits(*psw).eaba == PSW_BITS_AMODE_31BIT)
-		return ga & ((1UL << 31) - 1);
-	return ga & ((1UL << 24) - 1);
+	return _kvm_s390_logical_to_effective(&vcpu->arch.sie_block->gpsw, ga);
 }
 
 /*