[Qemu-ppc] pseries machine does not like older CPUs anymore

[Thomas Huth]

 Hi Bharata,

there seems to be a regression with current QEMU master: The pseries
machine does not work with older 64-bit ppc CPUs anymore. With QEMU
2.6.0, it is possible to run:

 qemu-system-ppc64 -nographic -M pseries -cpu 970

or

 qemu-system-ppc64 -nographic -M pseries -cpu POWER5+

but with QEMU master, I now only get a "Unable to find sPAPR CPU Core
definition" error message and then QEMU quits.

At a quick glance, this seems to be related to the new CPU hotplug
code... so could you maybe have a look?

 Thanks,
  Thomas