Re: [PATCH 2/2] hw/arm/sbsa-ref: Add cpu-map to device tree

[Marcin Juszkiewicz]

W dniu 27.12.2023 o 13:07, Xiong Yining pisze:
> From: xiongyining1480 <xiongyining1480@phytium.com.cn>
>
> Support CPU topology description through device tree.
>
> Signed-off-by: Xiong Yining <xiongyining1480@phytium.com.cn>
> Signed-off-by: Chen Baozi <chenbaozi@phytium.com.cn>
> ---
>   hw/arm/sbsa-ref.c | 35 +++++++++++++++++++++++++++++++++++
>   1 file changed, 35 insertions(+)
>
> diff --git a/hw/arm/sbsa-ref.c b/hw/arm/sbsa-ref.c
> index e6cd612bc5..a3c851148a 100644
> --- a/hw/arm/sbsa-ref.c
> +++ b/hw/arm/sbsa-ref.c
> @@ -283,10 +283,45 @@ static void create_fdt(SBSAMachineState *sms)
>                   ms->possible_cpus->cpus[cs->cpu_index].props.node_id);
>           }
>   
> +        qemu_fdt_setprop_cell(sms->fdt, nodename, "phandle",
> +                        qemu_fdt_alloc_phandle(sms->fdt));
> +
>           g_free(nodename);
>       }
>   
> +
>       sbsa_fdt_add_gic_node(sms);

Can you add vCPU topology code before ^^ line? So code would add /cpus/ 
node and then go for /intc/ node.

> +
> +    /*
> +     * Add vCPU topology description through fdt node cpu-map.

Maybe worth adding pointer to hw/arm/virt.c code for longer description?

> +     */
> +    qemu_fdt_add_subnode(sms->fdt, "/cpus/cpu-map");
> +
> +    for (cpu = sms->smp_cpus - 1; cpu >= 0; cpu--) {
> +        char *cpu_path = g_strdup_printf("/cpus/cpu@%d", cpu);
> +        char *map_path;
> +
> +        if (ms->smp.threads > 1) {
> +            map_path = g_strdup_printf(
> +                "/cpus/cpu-map/socket%d/cluster%d/core%d/thread%d",
> +                cpu / (ms->smp.clusters * ms->smp.cores * ms->smp.threads),
> +                (cpu / (ms->smp.cores * ms->smp.threads)) % ms->smp.clusters,
> +                (cpu / ms->smp.threads) % ms->smp.cores,
> +                cpu % ms->smp.threads);
> +        } else {
> +            map_path = g_strdup_printf(
> +                "/cpus/cpu-map/socket%d/cluster%d/core%d",
> +                cpu / (ms->smp.clusters * ms->smp.cores),
> +                (cpu / ms->smp.cores) % ms->smp.clusters,
> +                cpu % ms->smp.cores);
> +        }
> +        qemu_fdt_add_path(sms->fdt, map_path);
> +        qemu_fdt_setprop_phandle(sms->fdt, map_path, "cpu", cpu_path);
> +
> +        g_free(map_path);
> +        g_free(cpu_path);
> +    }
> +
>   }
>   
>   #define SBSA_FLASH_SECTOR_SIZE (256 * KiB)