libvirt: add clock config

Signed-off-by: Peng Tao <bergwolf@gmail.com>

Author: bergwolf

hypervisor/libvirt/libvirt.go

@@ -372,6 +372,27 @@ type qemucmd struct {
 	Value string `xml:"value,attr"`
 }
 
+type clock struct {
+	Offset string  `xml:"offset,attr"`
+	Timer  []timer `xml:"timer,omitempty"`
+}
+
+type timer struct {
+	Name       string  `xml:"name,attr"`
+	Track      string  `xml:"track,attr,omitempty"`
+	Tickpolicy string  `xml:"tickpolicy,attr,omitempty"`
+	CatchUp    catchup `xml:"catchup,omitempty"`
+	Frequency  uint32  `xml:"frequency,attr,omitempty"`
+	Mode       string  `xml:"mode,attr,omitempty"`
+	Present    string  `xml:"present,attr,omitempty"`
+}
+
+type catchup struct {
+	Threshold uint `xml:"threshold,attr,omitempty"`
+	Slew      uint `xml:"slew,attr,omitempty"`
+	Limit     uint `xml:"limit,attr,omitempty"`
+}
+
 type commandlines struct {
 	Cmds []qemucmd `xml:"qemu:arg"`
 }
@@ -392,6 +413,7 @@ type domain struct {
 	OnCrash     string       `xml:"on_crash"`
 	Devices     device       `xml:"devices"`
 	SecLabel    seclab       `xml:"seclabel"`
+	Clock       clock        `xml:"clock"`
 	CommandLine commandlines `xml:"qemu:commandline"`
 }
 
@@ -480,6 +502,9 @@ func (lc *LibvirtContext) domainXml(ctx *hypervisor.VmContext) (string, error) {
 	dom.OnReboot = "destroy"
 	dom.OnCrash = "destroy"
 
+	dom.Clock.Offset = "utc"
+	dom.Clock.Timer = append(dom.Clock.Timer, timer{Name: "rtc", Track: "guest", Tickpolicy: "catchup"})
+
 	pcicontroller := controller{
 		Type:  "pci",
 		Index: "0",