Panic device type used depends on 'model' attribute.
If no model is specified then device type depends on hypervisor
and guest arch. 'pseries' model is used for pSeries guest and
'isa' model is used in other cases.
XML:
<devices>
<panic model='hyperv'/>
</devices>
QEMU command line:
qemu -cpu <cpu_model>,hv_crash
