When a compatibility mode is requested on the command line, only the boot CPU core is correctly advertised in the device tree. Any other CPU core, either hot-plugged or cold-plugged, appears to be in raw mode with the host PVR.
Guest started on a POWER8 host with: -smp cores=2 -machine pseries,max-cpu-compat=compat7 # dtc -f -I fs -O dts /proc/device-tree | egrep 'cpu-version|pa-features' ibm,pa-features = [18 00 f6 3f c7 c0 80 f0 80 00 00 00 00 00 00 00 00 00 80 00 80 00 80 00 00 00]; cpu-version = <0x4d0200>; ^^^ second CPU core ibm,pa-features = <0x600f63f 0xc70080c0>; cpu-version = <0xf000003>; ^^^ boot CPU core This happens because the compatibility mode for any CPU but the boot one is set after the device tree was populated, and exposed to the guest. This series fixes the issue by setting the compatibility mode during CPU reset. This is done in the last patch. The first two patches are preliminary cleanup of the CPU reset and CPU hotplug paths. They are not strictly needed, but I think they are valuable anyway. -- Greg --- Greg Kurz (3): spapr: drop duplicate variable in spapr_core_plug() spapr_cpu_core: don't reset CPUs during realization spapr: fix device tree properties when using compatibility mode hw/ppc/spapr.c | 30 ++++++++++++++++++------------ hw/ppc/spapr_cpu_core.c | 15 +++++++++++++-- hw/ppc/spapr_rtas.c | 9 --------- include/hw/ppc/spapr_cpu_core.h | 2 ++ 4 files changed, 33 insertions(+), 23 deletions(-)