The way SMT thread siblings are matched is clunky, using hard-coded
logic that checks the PIR SPR.

Change that to use a new core_index variable in the CPUPPCState,
where all siblings have the same core_index. CPU realize routines have
flexibility in setting core/sibling topology.

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/cpu.h        | 9 +++++----
 hw/ppc/pnv_core.c       | 2 ++
 hw/ppc/spapr_cpu_core.c | 4 ++++
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 95ba9e7590..7b52a9bb18 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -1247,6 +1247,9 @@ struct CPUArchState {
     /* when a memory exception occurs, the access type is stored here */
     int access_type;
 
+    /* For SMT processors */
+    int core_index;
+
 #if !defined(CONFIG_USER_ONLY)
     /* MMU context, only relevant for full system emulation */
 #if defined(TARGET_PPC64)
@@ -1402,12 +1405,10 @@ struct CPUArchState {
     uint64_t pmu_base_time;
 };
 
-#define _CORE_ID(cs)                                            \
-    (POWERPC_CPU(cs)->env.spr_cb[SPR_PIR].default_value & ~(cs->nr_threads - 1))
-
 #define THREAD_SIBLING_FOREACH(cs, cs_sibling)                  \
     CPU_FOREACH(cs_sibling)                                     \
-        if (_CORE_ID(cs) == _CORE_ID(cs_sibling))
+        if (POWERPC_CPU(cs)->env.core_index ==                  \
+            POWERPC_CPU(cs_sibling)->env.core_index)
 
 #define SET_FIT_PERIOD(a_, b_, c_, d_)          \
 do {                                            \
diff --git a/hw/ppc/pnv_core.c b/hw/ppc/pnv_core.c
index 28ca61926d..7bda29b9c7 100644
--- a/hw/ppc/pnv_core.c
+++ b/hw/ppc/pnv_core.c
@@ -249,6 +249,8 @@ static void pnv_core_cpu_realize(PnvCore *pc, PowerPCCPU *cpu, Error **errp,
     pir_spr->default_value = pir;
     tir_spr->default_value = tir;
 
+    env->core_index = core_hwid;
+
     /* Set time-base frequency to 512 MHz */
     cpu_ppc_tb_init(env, PNV_TIMEBASE_FREQ);
 }
diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
index 21920ea054..4e13e6993a 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -302,11 +302,13 @@ static PowerPCCPU *spapr_create_vcpu(SpaprCpuCore *sc, int i, Error **errp)
     g_autofree char *id = NULL;
     CPUState *cs;
     PowerPCCPU *cpu;
+    CPUPPCState *env;
 
     obj = object_new(scc->cpu_type);
 
     cs = CPU(obj);
     cpu = POWERPC_CPU(obj);
+    env = &cpu->env;
     /*
      * All CPUs start halted. CPU0 is unhalted from the machine level reset code
      * and the rest are explicitly started up by the guest using an RTAS call.
@@ -317,6 +319,8 @@ static PowerPCCPU *spapr_create_vcpu(SpaprCpuCore *sc, int i, Error **errp)
         return NULL;
     }
 
+    env->core_index = cc->core_id;
+
     cpu->node_id = sc->node_id;
 
     id = g_strdup_printf("thread[%d]", i);
-- 
2.45.1