Re: [RFC 06/52] hw/cpu: Introduce hybrid CPU topology

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 13/2/23 10:49, Zhao Liu wrote:
> From: Zhao Liu <zhao1.liu@intel.com>
> 
> For smp systems, the parts in one topology level are the same. But now
> there are more and more systems with hybrid architectures. Different
> parts of the same topology level may have differences. For example,
> Intel's Alder Lake series CPU has two types of cores, so the CPU
> topology is no longer symmetrical.
> 
> The hybrid topology is compatible with the smp topology type, that is,
> different parts on the same level of the hybrid topology can set to be
> the same, but the hybrid topology will introduce more complexity (need
> to allocate more memory, organized with array or linked-list), so the
> original smp topology support is retained while introducing the hybrid
> topology, and the hybrid topology is only built when the hybrid is
> explicitly required.
> 
> Therefore, we introduce the definition support of hybrid cpu topology
> here. At the same time, in order to unify with the original smp, we
> introduce a new cpu topology structure that can support smp topology
> or hybrid topology. This structure will replace the CpuTopology type (in
> include/hw/boards.h) used by MachineState.smp.
> 
> As for now, we only support two hybrid topology levels: core and
> cluster.
> 
> Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
> ---
>   MAINTAINERS                   |   1 +
>   include/hw/cpu/cpu-topology.h | 117 ++++++++++++++++++++++++++++++++++
>   qapi/machine.json             |  12 ++++
>   3 files changed, 130 insertions(+)
>   create mode 100644 include/hw/cpu/cpu-topology.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 58794885ced3..918a9418d98e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1742,6 +1742,7 @@ F: qapi/machine-target.json
>   F: include/hw/boards.h
>   F: include/hw/core/cpu.h
>   F: include/hw/cpu/cluster.h
> +F: include/hw/cpu/cpu-topology.h
>   F: include/sysemu/numa.h
>   F: tests/unit/test-smp-parse.c
>   T: git https://gitlab.com/ehabkost/qemu.git machine-next

Worth splitting this section in 2, machine VS numa/clusters?