Re: [PATCH v3 11/19] ppc/pnv: Add allow for big-core differences in DT generation

[Cédric Le Goater]

On 7/16/24 18:26, Nicholas Piggin wrote:
> device-tree building needs to account for big-core mode, because it is
> driven by qemu cores (small cores). Every second core should be skipped,
> and every core should describe threads for both small-cores that make
> up the big core.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>


Reviewed-by: Cédric Le Goater <clg@redhat.com>

Thanks,

C.


> ---
>   hw/ppc/pnv.c | 43 +++++++++++++++++++++++++++++++++++--------
>   1 file changed, 35 insertions(+), 8 deletions(-)
>
> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
> index d902860ecd..1d08176b75 100644
> --- a/hw/ppc/pnv.c
> +++ b/hw/ppc/pnv.c
> @@ -141,9 +141,9 @@ static int pnv_dt_core(PnvChip *chip, PnvCore *pc, void 
> *fdt)
>       CPUPPCState *env = &cpu->env;
>       PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cs);
>       PnvChipClass *pnv_cc = PNV_CHIP_GET_CLASS(chip);
> -    g_autofree uint32_t *servers_prop = g_new(uint32_t, smt_threads);
> +    uint32_t *servers_prop;
>       int i;
> -    uint32_t pir;
> +    uint32_t pir, tir;
>       uint32_t segs[] = {cpu_to_be32(28), cpu_to_be32(40),
>                          0xffffffff, 0xffffffff};
>       uint32_t tbfreq = PNV_TIMEBASE_FREQ;
> @@ -154,7 +154,10 @@ static int pnv_dt_core(PnvChip *chip, PnvCore *pc, void 
> *fdt)
>       char *nodename;
>       int cpus_offset = get_cpus_node(fdt);
>   
> -    pnv_cc->get_pir_tir(chip, pc->hwid, 0, &pir, NULL);
> +    pnv_cc->get_pir_tir(chip, pc->hwid, 0, &pir, &tir);
> +
> +    /* Only one DT node per (big) core */
> +    g_assert(tir == 0);
>   
>       nodename = g_strdup_printf("%s@%x", dc->fw_name, pir);
>       offset = fdt_add_subnode(fdt, cpus_offset, nodename);
> @@ -235,12 +238,28 @@ static int pnv_dt_core(PnvChip *chip, PnvCore *pc, void 
> *fdt)
>       }
>   
>       /* Build interrupt servers properties */
> -    for (i = 0; i < smt_threads; i++) {
> -        pnv_cc->get_pir_tir(chip, pc->hwid, i, &pir, NULL);
> -        servers_prop[i] = cpu_to_be32(pir);
> +    if (pc->big_core) {
> +        servers_prop = g_new(uint32_t, smt_threads * 2);
> +        for (i = 0; i < smt_threads; i++) {
> +            pnv_cc->get_pir_tir(chip, pc->hwid, i, &pir, NULL);
> +            servers_prop[i * 2] = cpu_to_be32(pir);
> +
> +            pnv_cc->get_pir_tir(chip, pc->hwid + 1, i, &pir, NULL);
> +            servers_prop[i * 2 + 1] = cpu_to_be32(pir);
> +        }
> +        _FDT((fdt_setprop(fdt, offset, "ibm,ppc-interrupt-server#s",
> +                          servers_prop, sizeof(*servers_prop) * smt_threads
> +                                        * 2)));
> +    } else {
> +        servers_prop = g_new(uint32_t, smt_threads);
> +        for (i = 0; i < smt_threads; i++) {
> +            pnv_cc->get_pir_tir(chip, pc->hwid, i, &pir, NULL);
> +            servers_prop[i] = cpu_to_be32(pir);
> +        }
> +        _FDT((fdt_setprop(fdt, offset, "ibm,ppc-interrupt-server#s",
> +                          servers_prop, sizeof(*servers_prop) * smt_threads)));
>       }
> -    _FDT((fdt_setprop(fdt, offset, "ibm,ppc-interrupt-server#s",
> -                       servers_prop, sizeof(*servers_prop) * smt_threads)));
> +    g_free(servers_prop);
>   
>       return offset;
>   }
> @@ -389,6 +408,10 @@ static void pnv_chip_power9_dt_populate(PnvChip *chip, 
> void *fdt)
>   
>           _FDT((fdt_setprop(fdt, offset, "ibm,pa-features",
>                              pa_features_300, sizeof(pa_features_300))));
> +
> +        if (pnv_core->big_core) {
> +            i++; /* Big-core groups two QEMU cores */
> +        }
>       }
>   
>       if (chip->ram_size) {
> @@ -450,6 +473,10 @@ static void pnv_chip_power10_dt_populate(PnvChip *chip, 
> void *fdt)
>   
>           _FDT((fdt_setprop(fdt, offset, "ibm,pa-features",
>                              pa_features_31, sizeof(pa_features_31))));
> +
> +        if (pnv_core->big_core) {
> +            i++; /* Big-core groups two QEMU cores */
> +        }
>       }
>   
>       if (chip->ram_size) {