If the machine supports para virtual guests, then you should see a “pae” flag in /proc/info. This means – the machine has PAE support and can run para virtual guests.
[root@unixfoo root]# cat /proc/cpuinfo | grep pae
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm nx lm
[root@unixfoo root]#
If there is no output for the above command, then the machine is not capable of running a para-virtualized guest.