[Qemu-ppc] [RFC 00/17] Clean up compatibility mode handling

[David Gibson]

This series is a significant rework to how we handle CPU compatibility
modes on ppc.

 * Information about compatibility modes was previously open coded and
   scattered across a number of functions in both target-ppc and spapr
   code.  It's now brought together into a common table of
   compatibility modes.

 * There was significant conceptual confusion about what a
   compatibility mode means, and how it interacts with the machine
   type.  This cleans that up, clarifying that a compatibility mode
   (as an externally set option) only makes sense on machine types
   that don't permit the guest hypervisor privilege (i.e. 'pseries')
 
 * It was previously the user's (or management layer's) responsibility
   to determine compatibility of CPUs on either end for migration.
   This uses the compatibility modes to check that properly during an
   incoming migration.

 * Some ill-considered sanity checks broke migration from 2.6 to 2.7,
   due to some new instruction classes being added.  This should avoid
   a repeat of that problem for 2.8 (we may be able to backport a
   minimal subset to 2.7-stable to fix the existing problem).

Patches 1-5 are preliminary cleanups which could stand on their own.
Patches 6-16 are the compatibility mode cleanup proper.

So far, this has been mimimally tested.  There are quite a few
migration cases to check.

David Gibson (17):
  ppc: Remove some stub POWER6 models
  powernv: CPU compatibility modes don't make sense for powernv
  pseries: Always use core objects for CPU construction
  pseries: Make cpu_update during CAS unconditional
  ppc: Clean up and QOMify hypercall emulation
  ppc: Rename cpu_version to compat_pvr
  ppc: Rewrite ppc_set_compat()
  ppc: Rewrite ppc_get_compat_smt_threads()
  ppc: Validate compatibility modes when setting
  pseries: Rewrite CAS PVR compatibility logic
  ppc: Add ppc_set_compat_all()
  ppc: Migrate compatibility mode
  pseries: Move CPU compatibility property to machine
  pseries: Reset CPU compatibility mode
  ppc: Check that CPU model stays consistent across migration
  ppc: Remove counter-productive "sanity checks" in migration
  pseries: Default to POWER8 compatibility mode

 hw/ppc/pnv.c                |   6 +-
 hw/ppc/spapr.c              | 159 ++++++++++++++++------------
 hw/ppc/spapr_cpu_core.c     |  84 +++++++++++----
 hw/ppc/spapr_hcall.c        | 142 ++++++++-----------------
 hw/ppc/trace-events         |   2 +-
 include/hw/ppc/spapr.h      |  12 ++-
 target-ppc/Makefile.objs    |   1 +
 target-ppc/compat.c         | 251 ++++++++++++++++++++++++++++++++++++++++++++
 target-ppc/cpu-models.c     |   4 -
 target-ppc/cpu-models.h     |   2 -
 target-ppc/cpu.h            |  49 +++++++--
 target-ppc/excp_helper.c    |  11 +-
 target-ppc/kvm.c            |   4 +-
 target-ppc/kvm_ppc.h        |   4 +-
 target-ppc/machine.c        |  55 ++++++++--
 target-ppc/translate_init.c | 146 +++-----------------------
 16 files changed, 564 insertions(+), 368 deletions(-)
 create mode 100644 target-ppc/compat.c

-- 
2.7.4