1 files changed, 25 insertions, 0 deletions

diff --git a/arch/s390/kvm/gaccess.h b/arch/s390/kvm/gaccess.h
index 374a439ccc60..ae3cb638f220 100644
--- a/arch/s390/kvm/gaccess.h
+++ b/arch/s390/kvm/gaccess.h
@@ -30,6 +30,31 @@ static inline unsigned long kvm_s390_real_to_abs(struct kvm_vcpu *vcpu,
         return gaddr;
 }
 
+/**
+ * kvm_s390_logical_to_effective - convert guest logical to effective address
+ * @vcpu: guest virtual cpu
+ * @ga: guest logical address
+ *
+ * Convert a guest vcpu logical address to a guest vcpu effective address by
+ * applying the rules of the vcpu's addressing mode defined by PSW bits 31
+ * and 32 (extendended/basic addressing mode).
+ *
+ * Depending on the vcpu's 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(struct kvm_vcpu *vcpu,
+                                                          unsigned long ga)
+{
+        psw_t *psw = &vcpu->arch.sie_block->gpsw;
+
+        if (psw_bits(*psw).eaba == PSW_AMODE_64BIT)
+                return ga;
+        if (psw_bits(*psw).eaba == PSW_AMODE_31BIT)
+                return ga & ((1UL << 31) - 1);
+        return ga & ((1UL << 24) - 1);
+}
+
 static inline void __user *__gptr_to_uptr(struct kvm_vcpu *vcpu,
                                           void __user *gptr,
                                           int prefixing)