I'm still having problems with this. I've dug around and found errors in the qemu-dm log. When I try to start the VM with libvirt, the error I'm getting is: "xs_read(/vm/414e73de-cf1e-487c-87e0-d4ebf7a23576/rtc/timeoffset): read error" I did a xenstore-ls on the /vm/414e73de-cf1e-487c-87e0-d4ebf7a23576 directory and sure enough, rtc/timeoffset is not there. When I start the VM with the Xen config file I used to generate the XML the rtc/timeoffset is there (timeoffset is set to "0"). Is there a way to set that in the XML? I didn't see it in the online XML description. I'm using a slightly different XML description than I had originally so I've included here (along with the Xen Config file) Thanks! -matthew const char* foo = "<domain type='xen'>" "<name>LinuxVM</name>" "<uuid>414e73de-cf1e-487c-87e0-d4ebf7a23576</uuid>" "<os>" "<type>hvm</type>" "<loader>/usr/lib/xen/boot/hvmloader</loader>" "<boot dev='hd'/>" "</os>" "<memory>512000</memory>" "<vcpu>1</vcpu>" "<on_shutdown>shutdown</on_shutdown>" "<on_reboot>restart</on_reboot>" "<on_crash>restart</on_crash>" "<features>" "<pae/>" "<acpi/>" "<apic/>" "</features>" "<clock sync='localtime'/>" "<devices>" "<emulator>/usr/lib/xen/bin/qemu-dm</emulator>" "<disk type='block'>" "<source dev='/dev/vgvms/LinuxVM'/>" "<target dev='hda'/>" "</disk>" "<interface type='ioemu'>" "<mac address='7A:AB:D0:01:82:98'/>" "</interface>" "<input type='tablet' bus='usb'/>" "<graphics type='sdl' password=''/>" "<serial type='pty'/>" "</devices>" "</domain>"; //serial = "pty" int main (int argc, char** argv) { virConnectPtr con; /* connection to the Xen hypervisor */ virDomainPtr domain; virInitialize(); con = virConnectOpen ("xen:///"); if (!con) { virErrorPtr err = virGetLastError (); printf ("virConnectOpen failed: %s\n", err->message); return -1; } domain = virDomainDefineXML (con, foo); if (!domain) { virErrorPtr err = virConnGetLastError (con); printf ("virDomainDefineXML failed: %s\n", err->message); } else { if (virDomainCreate (domain) < 0) { virErrorPtr err = virConnGetLastError (con); printf ("virDomainCreate failed: %s\n", err->message); } else { virDomainInfo info = {0}; virDomainGetInfo (domain, &info); printf ("state = %d\n", info.state); getchar (); } } virConnectClose (con); return 0; } # Automatically generated xen config file name = "LinuxVM" builder = "hvm" memory = "500" disk = [ 'phy:/dev/vgvms/LinuxVM,hda,w', ] vif = [ 'type=ioemu, mac=7A:AB:D0:01:82:98', ] uuid = "414e73de-cf1e-487c-87e0-d4ebf7a23576" device_model = "/usr/lib/xen/bin/qemu-dm" kernel = "/usr/lib/xen/boot/hvmloader" vnc=1 vnc=0 sdl=1 stdvga=0 boot="cda" usbdevice="tablet" vncunused=1 apic=1 acpi=1 pae=1 vcpus=1 serial = "pty" on_reboot = 'restart' on_crash = 'restart'