diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index c69d382d70..98cac90720 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -7136,7 +7136,7 @@ virDomainDeviceInfoFormat(virBufferPtr buf,
 
     case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_SPAPRVIO:
         if (info->addr.spaprvio.has_reg)
-            virBufferAsprintf(&attrBuf, " reg='0x%llx'", info->addr.spaprvio.reg);
+            virBufferAsprintf(&attrBuf, " reg='0x%08llx'", info->addr.spaprvio.reg);
         break;
 
     case VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW:
diff --git a/tests/qemuxml2xmloutdata/disk-scsi.xml b/tests/qemuxml2xmloutdata/disk-scsi.xml
index 9cfff4b14e..45fed6423a 100644
--- a/tests/qemuxml2xmloutdata/disk-scsi.xml
+++ b/tests/qemuxml2xmloutdata/disk-scsi.xml
@@ -62,7 +62,7 @@
       <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
     </controller>
     <controller type='scsi' index='3' model='ibmvscsi'>
-      <address type='spapr-vio' reg='0x2000'/>
+      <address type='spapr-vio' reg='0x00002000'/>
     </controller>
     <controller type='pci' index='0' model='pci-root'/>
     <input type='mouse' bus='ps2'/>
diff --git a/tests/qemuxml2xmloutdata/pseries-nvram.xml b/tests/qemuxml2xmloutdata/pseries-nvram.xml
index f89b23b338..fd77c7aa89 100644
--- a/tests/qemuxml2xmloutdata/pseries-nvram.xml
+++ b/tests/qemuxml2xmloutdata/pseries-nvram.xml
@@ -23,7 +23,7 @@
     </controller>
     <memballoon model='none'/>
     <nvram>
-      <address type='spapr-vio' reg='0x4000'/>
+      <address type='spapr-vio' reg='0x00004000'/>
     </nvram>
     <panic model='pseries'/>
   </devices>