diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 863377ca85..a382d30098 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -985,11 +985,23 @@
           <dt><code>utc</code></dt>
           <dd>
             The guest clock will always be synchronized to UTC when
-            booted</dd>
+            booted.
+            <span class="since">Since 0.9.11</span> 'utc' mode can be converted
+            to 'variable' mode, which can be controlled by using the
+            <code>adjustment</code> attribute. If the value is 'reset', the
+            conversion is never done (not all hypervisors can
+            synchronize to UTC on each boot; use of 'reset' will cause
+            an error on those hypervisors). A numeric value
+            forces the conversion to 'variable' mode using the value as the
+            initial adjustment. The default <code>adjustment</code> is
+            hypervisor specific.
+          </dd>
           <dt><code>localtime</code></dt>
           <dd>
             The guest clock will be synchronized to the host's configured
             timezone when booted, if any.
+            <span class="since">Since 0.9.11,</span> the <code>adjustment</code>
+            attribute behaves the same as in 'utc' mode.
           </dd>
           <dt><code>timezone</code></dt>
           <dd>
@@ -1000,12 +1012,16 @@
           <dt><code>variable</code></dt>
           <dd>
             The guest clock will have an arbitrary offset applied
-            relative to UTC. The delta relative to UTC is specified
+            relative to UTC or localtime, depending on the <code>basis</code>
+            attribute. The delta relative to UTC (or localtime) is specified
             in seconds, using the <code>adjustment</code> attribute.
             The guest is free to adjust the RTC over time and expect
-            that it will be honoured at next reboot. This is in
-            contrast to 'utc' mode, where the RTC adjustments are
+            that it will be honored at next reboot. This is in
+            contrast to 'utc' and 'localtime' mode (with the optional
+            attribute adjustment='reset'), where the RTC adjustments are
             lost at each reboot. <span class="since">Since 0.7.7</span>
+            <span class="since">Since 0.9.11</span> the <code>basis</code>
+            attribute can be either 'utc' (default) or 'localtime'.
           </dd>
         </dl>
         <p>
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 5ed47aca63..0cc04af5da 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -582,12 +582,22 @@
     <optional>
       <element name="clock">
         <choice>
-          <attribute name="offset">
-            <value>localtime</value>
-          </attribute>
-          <attribute name="offset">
-            <value>utc</value>
-          </attribute>
+          <group>
+            <attribute name="offset">
+              <choice>
+                <value>localtime</value>
+                <value>utc</value>
+              </choice>
+            </attribute>
+            <optional>
+              <attribute name='adjustment'>
+                <choice>
+                  <ref name='timeDelta'/>
+                  <value>reset</value>
+                </choice>
+              </attribute>
+            </optional>
+          </group>
           <group>
             <attribute name="offset">
               <value>timezone</value>
@@ -607,6 +617,14 @@
                 <ref name="timeDelta"/>
               </attribute>
             </optional>
+            <optional>
+              <attribute name="basis">
+                <choice>
+                  <value>utc</value>
+                  <value>localtime</value>
+                </choice>
+              </attribute>
+            </optional>
           </group>
         </choice>
         <zeroOrMore>
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index c800160441..cca757d607 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -590,6 +590,10 @@ VIR_ENUM_IMPL(virDomainClockOffset, VIR_DOMAIN_CLOCK_OFFSET_LAST,
               "variable",
               "timezone");
 
+VIR_ENUM_IMPL(virDomainClockBasis, VIR_DOMAIN_CLOCK_BASIS_LAST,
+              "utc",
+              "localtime");
+
 VIR_ENUM_IMPL(virDomainTimerName, VIR_DOMAIN_TIMER_NAME_LAST,
               "platform",
               "pit",
@@ -8069,10 +8073,53 @@ static virDomainDefPtr virDomainDefParseXML(virCapsPtr caps,
         def->clock.offset = VIR_DOMAIN_CLOCK_OFFSET_UTC;
     }
     switch (def->clock.offset) {
+    case VIR_DOMAIN_CLOCK_OFFSET_LOCALTIME:
+    case VIR_DOMAIN_CLOCK_OFFSET_UTC:
+        tmp = virXPathString("string(./clock/@adjustment)", ctxt);
+        if (tmp) {
+            if (STREQ(tmp, "reset")) {
+                def->clock.data.utc_reset = true;
+            } else {
+                char *conv = NULL;
+                unsigned long long val;
+                val = strtoll(tmp, &conv, 10);
+                if (conv == tmp || *conv != '\0') {
+                    virDomainReportError(VIR_ERR_INTERNAL_ERROR,
+                                         _("unknown clock adjustment '%s'"), tmp);
+                    goto error;
+                }
+                switch (def->clock.offset) {
+                case VIR_DOMAIN_CLOCK_OFFSET_LOCALTIME:
+                    def->clock.data.variable.basis = VIR_DOMAIN_CLOCK_BASIS_LOCALTIME;
+                    break;
+                case VIR_DOMAIN_CLOCK_OFFSET_UTC:
+                    def->clock.data.variable.basis = VIR_DOMAIN_CLOCK_BASIS_UTC;
+                    break;
+                }
+                def->clock.offset = VIR_DOMAIN_CLOCK_OFFSET_VARIABLE;
+                def->clock.data.variable.adjustment = val;
+            }
+            VIR_FREE(tmp);
+        } else {
+            def->clock.data.utc_reset = false;
+        }
+        break;
+
     case VIR_DOMAIN_CLOCK_OFFSET_VARIABLE:
         if (virXPathLongLong("number(./clock/@adjustment)", ctxt,
-                             &def->clock.data.adjustment) < 0)
-            def->clock.data.adjustment = 0;
+                             &def->clock.data.variable.adjustment) < 0)
+            def->clock.data.variable.adjustment = 0;
+        tmp = virXPathString("string(./clock/@basis)", ctxt);
+        if (tmp) {
+            if ((def->clock.data.variable.basis = virDomainClockBasisTypeFromString(tmp)) < 0) {
+                virDomainReportError(VIR_ERR_INTERNAL_ERROR,
+                                     _("unknown clock basis '%s'"), tmp);
+                goto error;
+            }
+            VIR_FREE(tmp);
+        } else {
+            def->clock.data.variable.basis = VIR_DOMAIN_CLOCK_BASIS_UTC;
+        }
         break;
 
     case VIR_DOMAIN_CLOCK_OFFSET_TIMEZONE:
@@ -12521,9 +12568,15 @@ virDomainDefFormatInternal(virDomainDefPtr def,
     virBufferAsprintf(buf, "  <clock offset='%s'",
                       virDomainClockOffsetTypeToString(def->clock.offset));
     switch (def->clock.offset) {
+    case VIR_DOMAIN_CLOCK_OFFSET_LOCALTIME:
+    case VIR_DOMAIN_CLOCK_OFFSET_UTC:
+        if (def->clock.data.utc_reset)
+            virBufferAddLit(buf, " adjustment='reset'");
+        break;
     case VIR_DOMAIN_CLOCK_OFFSET_VARIABLE:
-        virBufferAsprintf(buf, " adjustment='%lld'",
-                          def->clock.data.adjustment);
+        virBufferAsprintf(buf, " adjustment='%lld' basis='%s'",
+                          def->clock.data.variable.adjustment,
+                          virDomainClockBasisTypeToString(def->clock.data.variable.basis));
         break;
     case VIR_DOMAIN_CLOCK_OFFSET_TIMEZONE:
         virBufferEscapeString(buf, " timezone='%s'", def->clock.data.timezone);
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 3fcb02644c..0eed60e02a 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -1446,15 +1446,27 @@ enum virDomainClockOffsetType {
     VIR_DOMAIN_CLOCK_OFFSET_LAST,
 };
 
+enum virDomainClockBasis {
+    VIR_DOMAIN_CLOCK_BASIS_UTC = 0,
+    VIR_DOMAIN_CLOCK_BASIS_LOCALTIME = 1,
+
+    VIR_DOMAIN_CLOCK_BASIS_LAST,
+};
+
 typedef struct _virDomainClockDef virDomainClockDef;
 typedef virDomainClockDef *virDomainClockDefPtr;
 struct _virDomainClockDef {
     int offset;
 
     union {
-        /* Adjustment in seconds, relative to UTC, when
+        /* Bug-compatibility-mode for Xen utc|localtime */
+        int utc_reset;
+        /* Adjustment in seconds, relative to UTC or LOCALTIME, when
          * offset == VIR_DOMAIN_CLOCK_OFFSET_VARIABLE */
-        long long adjustment;
+        struct {
+            long long adjustment;
+            int basis;
+        } variable;
 
         /* Timezone name, when
          * offset == VIR_DOMAIN_CLOCK_OFFSET_LOCALTIME */
@@ -2176,6 +2188,7 @@ int virDomainStateReasonFromString(virDomainState state, const char *reason);
 
 VIR_ENUM_DECL(virDomainSeclabel)
 VIR_ENUM_DECL(virDomainClockOffset)
+VIR_ENUM_DECL(virDomainClockBasis)
 
 VIR_ENUM_DECL(virDomainTimerName)
 VIR_ENUM_DECL(virDomainTimerTrack)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 97fec2fcf4..a90f8a0fa2 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -255,6 +255,7 @@ virDomainChrTcpProtocolTypeFromString;
 virDomainChrTcpProtocolTypeToString;
 virDomainChrTypeFromString;
 virDomainChrTypeToString;
+virDomainClockBasisTypeToString;
 virDomainClockOffsetTypeFromString;
 virDomainClockOffsetTypeToString;
 virDomainConfigFile;
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index cfd5d756cb..ea9431fa31 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -3563,7 +3563,13 @@ qemuBuildClockArgStr(virDomainClockDefPtr def)
         time_t now = time(NULL);
         struct tm nowbits;
 
-        now += def->data.adjustment;
+        if (def->data.variable.basis != VIR_DOMAIN_CLOCK_BASIS_UTC) {
+            qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                            _("unsupported clock basis '%s'"),
+                            virDomainClockBasisTypeToString(def->data.variable.basis));
+            goto error;
+        }
+        now += def->data.variable.adjustment;
         gmtime_r(&now, &nowbits);
 
         virBufferAsprintf(&buf, "base=%d-%02d-%02dT%02d:%02d:%02d",
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 0667a03924..91f1c5b095 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -738,7 +738,7 @@ qemuProcessHandleRTCChange(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     event = virDomainEventRTCChangeNewFromObj(vm, offset);
 
     if (vm->def->clock.offset == VIR_DOMAIN_CLOCK_OFFSET_VARIABLE)
-        vm->def->clock.data.adjustment = offset;
+        vm->def->clock.data.variable.adjustment = offset;
 
     if (virDomainSaveStatus(driver->caps, driver->stateDir, vm) < 0)
         VIR_WARN("unable to save domain status with RTC change");
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-clock-variable.xml b/tests/qemuxml2argvdata/qemuxml2argv-clock-variable.xml
index 97c0aedb45..73103bbb3a 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-clock-variable.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-clock-variable.xml
@@ -8,7 +8,7 @@
     <type arch='i686' machine='pc'>hvm</type>
     <boot dev='hd'/>
   </os>
-  <clock offset='variable' adjustment='123456'/>
+  <clock offset='variable' adjustment='123456' basis='utc'/>
   <on_poweroff>destroy</on_poweroff>
   <on_reboot>restart</on_reboot>
   <on_crash>destroy</on_crash>