Re: [Qemu-ppc] [PATCHv4 0/5] Clean up compatibility mode handling

[Greg Kurz]

On Wed, 31 May 2017 12:57:48 +1000
David Gibson <address@hidden> wrote:
> [...]
> > All old non-pseries machine types already complain when started with
> > a POWER7 or newer CPU. Providing the extra error message looks weird:
> > 
> > qemu-system-ppc64 -machine ppce500 \
> >                   -cpu POWER7,compat=power6
> > qemu-system-ppc64: CPU 'compat' property is deprecated and has no effect;
> >  use max-cpu-compat machine property instead
> > MMU model 983043 not supported by this machine.
> > 
> > but I guess it's better than crashing. :)  
> 
> Well, sure POWER7 doesn't make sense for an e500 machine for other
> reasons.  But POWER7 or POWER8 _would_ make sense for powernv, where
> compat= doesn't.
> 

The powernv machine type doesn't even support CPU features at all:

    chip_typename = g_strdup_printf(TYPE_PNV_CHIP "-%s", machine->cpu_model);
    if (!object_class_by_name(chip_typename)) {
        error_report("invalid CPU model '%s' for %s machine",
                     machine->cpu_model, MACHINE_GET_CLASS(machine)->name);
        exit(1);
    }

> >   
> > > > 
> > > > This means that patch 1 is no longer needed if I get things right but
> > > > you probably want Markus to second that.
> > > >     
> > > > >   * Add a migration fix make cpu_synchronize_state() safe in post_load
> > > > >     handlers, which in turn fixes a bug in 5/5.
> > > > >   * A number of bugfixes and other tweaks suggested by feedback on v2.
> > > > > 
> > > > > Changes since RFCv2:
> > > > >   * Many patches dropped, since they're already merged
> > > > >   * Rebased, fixed conflicts
> > > > >   * Restored support for backwards migration (wasn't as complicated as
> > > > >     I thought)
> > > > >   * Updated final patch's description to more accurately reflect the
> > > > >     logic
> > > > > 
> > > > > Changes since RFCv1:
> > > > >   * Change CAS logic to prefer compatibility modes over raw mode
> > > > >   * Simplified by giving up on half-hearted attempts to maintain
> > > > >     backwards migration
> > > > >   * Folded migration stream changes into a single patch
> > > > >   * Removed some preliminary patches which are already merged
> > > > > 
> > > > > David Gibson (4):
> > > > >   migration: Mark CPU states dirty before incoming migration/loadvm
> > > > >   pseries: Move CPU compatibility property to machine
> > > > >   pseries: Reset CPU compatibility mode
> > > > >   ppc: Rework CPU compatibility testing across migration
> > > > > 
> > > > > Greg Kurz (1):
> > > > >   qapi: add explicit null to string input and output visitors
> > > > > 
> > > > >  cpus.c                       |   9 ++++
> > > > >  hw/ppc/spapr.c               |   8 +++-
> > > > >  hw/ppc/spapr_cpu_core.c      |  62 +++++++++++++++++++++-----
> > > > >  hw/ppc/spapr_hcall.c         |   8 ++--
> > > > >  include/hw/ppc/spapr.h       |  12 +++--
> > > > >  include/sysemu/cpus.h        |   1 +
> > > > >  include/sysemu/hax.h         |   1 +
> > > > >  include/sysemu/hw_accel.h    |  10 +++++
> > > > >  include/sysemu/kvm.h         |   1 +
> > > > >  kvm-all.c                    |  10 +++++
> > > > >  migration/savevm.c           |   2 +
> > > > >  qapi/string-input-visitor.c  |  11 +++++
> > > > >  qapi/string-output-visitor.c |  14 ++++++
> > > > >  target/i386/hax-all.c        |  10 +++++
> > > > >  target/ppc/compat.c          | 102 
> > > > > +++++++++++++++++++++++++++++++++++++++++++
> > > > >  target/ppc/cpu.h             |   5 ++-
> > > > >  target/ppc/machine.c         |  72 ++++++++++++++++++++++++++++--
> > > > >  target/ppc/translate_init.c  |  86 
> > > > > +++++++++++-------------------------
> > > > >  18 files changed, 340 insertions(+), 84 deletions(-)
> > > > >     
> > > >     
> > > 
> > > 
> > >   
> >   
> 
> 
>

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