RE: [RFC 09/52] hw/machine: Introduce core type for hybrid topology

["Mi, Dapeng1" <dapeng1.mi@intel.com>]

> From: Zhao Liu <zhao1.liu@linux.intel.com>
> Sent: Monday, February 13, 2023 5:50 PM
> To: Eduardo Habkost <eduardo@habkost.net>; Marcel Apfelbaum
> <marcel.apfelbaum@gmail.com>; Philippe Mathieu-Daudé <philmd@linaro.org>;
> Yanan Wang <wangyanan55@huawei.com>; Michael S . Tsirkin
> <mst@redhat.com>; Richard Henderson <richard.henderson@linaro.org>; Paolo
> Bonzini <pbonzini@redhat.com>; Eric Blake <eblake@redhat.com>; Markus
> Armbruster <armbru@redhat.com>
> Cc: qemu-devel@nongnu.org; Wang, Zhenyu Z <zhenyu.z.wang@intel.com>; Mi,
> Dapeng1 <dapeng1.mi@intel.com>; Ding, Zhuocheng
> <zhuocheng.ding@intel.com>; Robert Hoo <robert.hu@linux.intel.com>;
> Christopherson,, Sean <seanjc@google.com>; Like Xu
> <like.xu.linux@gmail.com>; Liu, Zhao1 <zhao1.liu@intel.com>
> Subject: [RFC 09/52] hw/machine: Introduce core type for hybrid topology
> 
> From: Zhao Liu <zhao1.liu@intel.com>
> 
> Under the hybrid cpu topology, some CPUs care about the core type.
> For example, Intel's Alder Lake series CPU contains two types of cores:
> Intel Core and Intel Atom. The type information of these two types is exposed in
> 1A leaf of CPUID.
> 
> Core type should also be part of the hybrid topology, and
> MachineState.cpu_type cannot provide different type information for different
> cpus in the same machine, so add a type field for the core level in the hybrid cpu
> topology.
> 
> Additionally, add a helper to get core type information from MachineState.
> Though core_type is only used in hybrid case, don't use assert since it may be
> used to initialize some generic fields.
> 
> Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
> ---
>  hw/core/machine-topo.c        | 12 ++++++++++++
>  include/hw/boards.h           |  3 +++
>  include/hw/cpu/cpu-topology.h |  2 ++
>  3 files changed, 17 insertions(+)
> 
> diff --git a/hw/core/machine-topo.c b/hw/core/machine-topo.c index
> b20160479629..e0ec07b53d42 100644
> --- a/hw/core/machine-topo.c
> +++ b/hw/core/machine-topo.c
> @@ -51,6 +51,18 @@ unsigned int machine_topo_get_smp_threads(const
> MachineState *ms)
>      return ms->topo.smp.threads;
>  }
> 
> +unsigned int machine_topo_get_hybrid_core_type(const MachineState *ms,
> +                                               unsigned int cluster_id,
> +                                               unsigned int core_id) {
> +    if (!machine_topo_is_smp(ms)) {
> +        return ms->topo.hybrid.cluster_list[cluster_id]
> +                       .core_list[core_id].core_type;
> +    } else {
> +        return 0;
> +    }
> +}
> +

We'd better not to return the hard-coded '0'. Suggest to define a 'enum'
data structure to represent the core_type. This makes the code look more intuitively.

>  unsigned int machine_topo_get_threads(const MachineState *ms,
>                                        unsigned int cluster_id,
>                                        unsigned int core_id) diff --git a/include/hw/boards.h
> b/include/hw/boards.h index 34b64b012022..78e52af38cb1 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -484,6 +484,9 @@ unsigned int machine_topo_get_dies(const
> MachineState *ms);  unsigned int machine_topo_get_clusters(const
> MachineState *ms);  unsigned int machine_topo_get_smp_cores(const
> MachineState *ms);  unsigned int machine_topo_get_smp_threads(const
> MachineState *ms);
> +unsigned int machine_topo_get_hybrid_core_type(const MachineState *ms,
> +                                               unsigned int cluster_id,
> +                                               unsigned int core_id);
>  unsigned int machine_topo_get_threads(const MachineState *ms,
>                                        unsigned int cluster_id,
>                                        unsigned int core_id); diff --git a/include/hw/cpu/cpu-
> topology.h b/include/hw/cpu/cpu-topology.h index
> 8268ea3a8569..87d832556229 100644
> --- a/include/hw/cpu/cpu-topology.h
> +++ b/include/hw/cpu/cpu-topology.h
> @@ -45,9 +45,11 @@ typedef struct SmpCpuTopology {
>  /**
>   * HybridCore - hybrid core topology defination:
>   * @threads: the number of threads in one core.
> + * @core_type: the type of current core.
>   */
>  typedef struct HybridCore {
>      unsigned int threads;
> +    unsigned int core_type;
>  } HybridCore;
> 
>  /**
> --
> 2.34.1