Re: [Qemu-devel] [RFC PATCH] target-ppc: Register CPU class per family only when needed

[Alexander Graf <agraf@suse.de>]

On 05.03.15 02:56, Alexey Kardashevskiy wrote:
> At the moment when running in KVM mode, QEMU registers "host" class to
> match the current CPU PVR value. It also registers another CPU class
> with a CPU family name os if we run QEMU on POWER7 machine, "host" and
> "POWER7" classes are created, this way we can always use "-cpu POWER7"
> on the actual POWER7 machine.
> 
> The existing code uses DeviceClass::desc field of the CPU class as
> a source for the class name; it was pointed out that it is wrong to use
> user-visible string as a type name.
> 
> This adds a common CPU class name into PowerPCCPUClass struct.
> This makes registration of a CPU named after the family conditional -
> PowerPCCPUClass::common_cpu_name has to be non-zero. Only POWER7/POWER8
> families have this field initialized by now.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

LGTM. Andreas, do you agree?


Alex


> ---
>  target-ppc/cpu-qom.h        |  1 +
>  target-ppc/kvm.c            | 11 ++++++-----
>  target-ppc/translate_init.c |  2 ++
>  3 files changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/target-ppc/cpu-qom.h b/target-ppc/cpu-qom.h
> index 6967a80..4b471d7 100644
> --- a/target-ppc/cpu-qom.h
> +++ b/target-ppc/cpu-qom.h
> @@ -55,6 +55,7 @@ typedef struct PowerPCCPUClass {
>      DeviceRealize parent_realize;
>      void (*parent_reset)(CPUState *cpu);
>  
> +    const char *common_cpu_name;
>      uint32_t pvr;
>      bool (*pvr_match)(struct PowerPCCPUClass *pcc, uint32_t pvr);
>      uint64_t pcr_mask;
> diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
> index b479471..3f2df65 100644
> --- a/target-ppc/kvm.c
> +++ b/target-ppc/kvm.c
> @@ -2221,7 +2221,6 @@ static int kvm_ppc_register_host_cpu_type(void)
>      };
>      uint32_t host_pvr = mfpvr();
>      PowerPCCPUClass *pvr_pcc;
> -    DeviceClass *dc;
>  
>      pvr_pcc = ppc_cpu_class_by_pvr(host_pvr);
>      if (pvr_pcc == NULL) {
> @@ -2235,10 +2234,12 @@ static int kvm_ppc_register_host_cpu_type(void)
>  
>      /* Register generic family CPU class for a family */
>      pvr_pcc = ppc_cpu_get_family_class(pvr_pcc);
> -    dc = DEVICE_CLASS(pvr_pcc);
> -    type_info.parent = object_class_get_name(OBJECT_CLASS(pvr_pcc));
> -    type_info.name = g_strdup_printf("%s-"TYPE_POWERPC_CPU, dc->desc);
> -    type_register(&type_info);
> +    if (pvr_pcc->common_cpu_name) {
> +        type_info.parent = object_class_get_name(OBJECT_CLASS(pvr_pcc));
> +        type_info.name = g_strdup_printf("%s-"TYPE_POWERPC_CPU,
> +                                         pvr_pcc->common_cpu_name);
> +        type_register(&type_info);
> +    }
>  
>      return 0;
>  }
> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
> index df1a62c..3d0be66 100644
> --- a/target-ppc/translate_init.c
> +++ b/target-ppc/translate_init.c
> @@ -8117,6 +8117,7 @@ POWERPC_FAMILY(POWER7)(ObjectClass *oc, void *data)
>      dc->fw_name = "PowerPC,POWER7";
>      dc->desc = "POWER7";
>      dc->props = powerpc_servercpu_properties;
> +    pcc->common_cpu_name = "POWER7";
>      pcc->pvr_match = ppc_pvr_match_power7;
>      pcc->pcr_mask = PCR_COMPAT_2_05 | PCR_COMPAT_2_06;
>      pcc->init_proc = init_proc_POWER7;
> @@ -8193,6 +8194,7 @@ POWERPC_FAMILY(POWER8)(ObjectClass *oc, void *data)
>      dc->fw_name = "PowerPC,POWER8";
>      dc->desc = "POWER8";
>      dc->props = powerpc_servercpu_properties;
> +    pcc->common_cpu_name = "POWER8";
>      pcc->pvr_match = ppc_pvr_match_power8;
>      pcc->pcr_mask = PCR_COMPAT_2_05 | PCR_COMPAT_2_06;
>      pcc->init_proc = init_proc_POWER8;
>