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

[Greg Kurz <groug@kaod.org>]

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.

> 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.

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);