Re: [PATCH v5 1/1] hw/arm/sbsa-ref: Enable CPU cluster on ARM sbsa machine

[Leif Lindholm]

On 2024-06-07 11:38, Xiong Yining wrote:
> Enable CPU cluster support on SbsaQemu platform, so that users can
> specify a 4-level CPU hierarchy sockets/clusters/cores/threads. And
> this topology can be passed to the firmware through /cpus/topology
> Device Tree.
>
> Signed-off-by: Xiong Yining <xiongyining1480@phytium.com.cn>
> tested-by: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org>

Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>

Thanks!

> ---
>   docs/system/arm/sbsa.rst |  4 ++++
>   hw/arm/sbsa-ref.c        | 11 ++++++++++-
>   2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst
> index 2bf22a1d0b..2bf3fc8d59 100644
> --- a/docs/system/arm/sbsa.rst
> +++ b/docs/system/arm/sbsa.rst
> @@ -62,6 +62,7 @@ The devicetree reports:
>      - platform version
>      - GIC addresses
>      - NUMA node id for CPUs and memory
> +   - CPU topology information
>   
>   Platform version
>   ''''''''''''''''
> @@ -88,3 +89,6 @@ Platform version changes:
>   
>   0.3
>     The USB controller is an XHCI device, not EHCI.
> +
> +0.4
> +  CPU topology information is present in devicetree.
> diff --git a/hw/arm/sbsa-ref.c b/hw/arm/sbsa-ref.c
> index e884692f07..9987850fc4 100644
> --- a/hw/arm/sbsa-ref.c
> +++ b/hw/arm/sbsa-ref.c
> @@ -223,7 +223,7 @@ static void create_fdt(SBSAMachineState *sms)
>        *                        fw compatibility.
>        */
>       qemu_fdt_setprop_cell(fdt, "/", "machine-version-major", 0);
> -    qemu_fdt_setprop_cell(fdt, "/", "machine-version-minor", 3);
> +    qemu_fdt_setprop_cell(fdt, "/", "machine-version-minor", 4);
>   
>       if (ms->numa_state->have_numa_distance) {
>           int size = nb_numa_nodes * nb_numa_nodes * 3 * sizeof(uint32_t);
> @@ -280,6 +280,14 @@ static void create_fdt(SBSAMachineState *sms)
>           g_free(nodename);
>       }
>   
> +    /* Add CPU topology description through fdt node topology. */
> +    qemu_fdt_add_subnode(sms->fdt, "/cpus/topology");
> +
> +    qemu_fdt_setprop_cell(sms->fdt, "/cpus/topology", "sockets", 
> ms->smp.sockets);
> +    qemu_fdt_setprop_cell(sms->fdt, "/cpus/topology", "clusters", 
> ms->smp.clusters);
> +    qemu_fdt_setprop_cell(sms->fdt, "/cpus/topology", "cores", ms->smp.cores);
> +    qemu_fdt_setprop_cell(sms->fdt, "/cpus/topology", "threads", 
> ms->smp.threads);
> +
>       sbsa_fdt_add_gic_node(sms);
>   }
>   
> @@ -902,6 +910,7 @@ static void sbsa_ref_class_init(ObjectClass *oc, void *data)
>       mc->default_ram_size = 1 * GiB;
>       mc->default_ram_id = "sbsa-ref.ram";
>       mc->default_cpus = 4;
> +    mc->smp_props.clusters_supported = true;
>       mc->possible_cpu_arch_ids = sbsa_ref_possible_cpu_arch_ids;
>       mc->cpu_index_to_instance_props = sbsa_ref_cpu_index_to_props;
>       mc->get_default_cpu_node_id = sbsa_ref_get_default_cpu_node_id;