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 <npig...@gmail.com>

Reviewed-by: Cédric Le Goater <c...@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) {