Re: [PATCH] spapr/kvm: Set default cpu model for all machine classes

[David Gibson <david@gibson.dropbear.id.au>]

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On Thu, Oct 31, 2019 at 09:15:56AM +0100, Greg Kurz wrote:
> On Wed, 30 Oct 2019 17:32:43 +0100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > We have to set the default model of all machine classes, not just for the
> > active one. Otherwise, "query-machines" will indicate the wrong CPU model
> > ("qemu-s390x-cpu" instead of "host-s390x-cpu") as "default-cpu-type".
> > 
> 
> A PPC cpu model might be better.

Indeed.

> 
> > s390x already fixed this in de60a92e "s390x/kvm: Set default cpu model for
> > all machine classes".  This patch applies a similar fix for the pseries-*
> > machine types on ppc64.
> > 
> > Doing a
> >     {"execute":"query-machines"}
> > under KVM now results in
> >     {
> >       "hotpluggable-cpus": true,
> >       "name": "pseries-4.2",
> >       "numa-mem-supported": true,
> >       "default-cpu-type": "host-powerpc64-cpu",
> >       "is-default": true,
> >       "cpu-max": 1024,
> >       "deprecated": false,
> >       "alias": "pseries"
> >     },
> >     {
> >       "hotpluggable-cpus": true,
> >       "name": "pseries-4.1",
> >       "numa-mem-supported": true,
> >       "default-cpu-type": "host-powerpc64-cpu",
> >       "cpu-max": 1024,
> >       "deprecated": false
> >     },
> >     ...
> > 
> > Libvirt probes all machines via "-machine none,accel=kvm:tcg" and will
> > currently see the wrong CPU model under KVM.
> > 
> > Reported-by: Jiři Denemark <jdenemar@redhat.com>
> > Cc: David Hildenbrand <david@redhat.com>
> > Cc: Igor Mammedov <imammedo@redhat.com>
> 
> Missing S-o-b.

Oops, fixed.

> With these fixed.
> 
> Reviewed-by: Greg Kurz <groug@kaod.org>
> 
> > ---
> >  target/ppc/kvm.c | 21 +++++++++++++--------
> >  1 file changed, 13 insertions(+), 8 deletions(-)
> > 
> > diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> > index 7d2e8969ac..c77f9848ec 100644
> > --- a/target/ppc/kvm.c
> > +++ b/target/ppc/kvm.c
> > @@ -100,7 +100,7 @@ static bool kvmppc_is_pr(KVMState *ks)
> >      return kvm_vm_check_extension(ks, KVM_CAP_PPC_GET_PVINFO) != 0;
> >  }
> >  
> > -static int kvm_ppc_register_host_cpu_type(MachineState *ms);
> > +static int kvm_ppc_register_host_cpu_type(void);
> >  static void kvmppc_get_cpu_characteristics(KVMState *s);
> >  static int kvmppc_get_dec_bits(void);
> >  
> > @@ -147,7 +147,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
> >          exit(1);
> >      }
> >  
> > -    kvm_ppc_register_host_cpu_type(ms);
> > +    kvm_ppc_register_host_cpu_type();
> >  
> >      return 0;
> >  }
> > @@ -2534,13 +2534,19 @@ PowerPCCPUClass *kvm_ppc_get_host_cpu_class(void)
> >      return pvr_pcc;
> >  }
> >  
> > -static int kvm_ppc_register_host_cpu_type(MachineState *ms)
> > +static void pseries_machine_class_fixup(ObjectClass *oc, void *opaque)
> > +{
> > +    MachineClass *mc = MACHINE_CLASS(oc);
> > +
> > +    mc->default_cpu_type = TYPE_HOST_POWERPC_CPU;
> > +}
> > +
> > +static int kvm_ppc_register_host_cpu_type(void)
> >  {
> >      TypeInfo type_info = {
> >          .name = TYPE_HOST_POWERPC_CPU,
> >          .class_init = kvmppc_host_cpu_class_init,
> >      };
> > -    MachineClass *mc = MACHINE_GET_CLASS(ms);
> >      PowerPCCPUClass *pvr_pcc;
> >      ObjectClass *oc;
> >      DeviceClass *dc;
> > @@ -2552,10 +2558,9 @@ static int kvm_ppc_register_host_cpu_type(MachineState *ms)
> >      }
> >      type_info.parent = object_class_get_name(OBJECT_CLASS(pvr_pcc));
> >      type_register(&type_info);
> > -    if (object_dynamic_cast(OBJECT(ms), TYPE_SPAPR_MACHINE)) {
> > -        /* override TCG default cpu type with 'host' cpu model */
> > -        mc->default_cpu_type = TYPE_HOST_POWERPC_CPU;
> > -    }
> > +    /* override TCG default cpu type with 'host' cpu model */
> > +    object_class_foreach(pseries_machine_class_fixup, TYPE_SPAPR_MACHINE,
> > +                         false, NULL);
> >  
> >      oc = object_class_by_name(type_info.name);
> >      g_assert(oc);
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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