[Qemu-devel] CPU hotplug on POWER9 (TCG) fails in ppc_radix64_handle_mmu_fault

[Cédric Le Goater]

Hi, 

Today, if you try to hotplug a CPU on a POWER9 guest (TCG), it fails
with an assert on the LPCR_UPRT bit missing in ppc_radix64_handle_mmu_fault()

  (qemu) device_add POWER9_v1.0-spapr-cpu-core,core-id=4,id=foo
  (qemu) [   12.766102] pseries-hotplug-cpu: Attempting to add CPU, drc index: 
10000004
  qemu-system-ppc64: ./target/ppc/mmu-radix64.c:204: 
ppc_radix64_handle_mmu_fault: Assertion `ppc64_use_proc_tbl(cpu)' failed.
  Aborted (core dumped)

The LPCR SPR is incorrectly set. I have hacked my way through to make 
it work, by changing cpu_ppc_set_papr(), but this is really ugly and 
certainly wrong. 

I would happy to cook the fix, as I need it for XIVE development. What
would be the correct approach ?    

Thanks,

C.