[RFC PATCH 06/10] ppc: Add a core_index to CPUPPCState for SMT vCPUs

[Nicholas Piggin <npiggin@gmail.com>]

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.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/cpu.h        | 5 ++++-
 hw/ppc/pnv_core.c       | 2 ++
 hw/ppc/spapr_cpu_core.c | 3 +++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index dac13d4dac..9a89083932 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)
@@ -1404,7 +1407,7 @@ struct CPUArchState {
 };
 
 #define _CORE_ID(cs)                                            \
-    (POWERPC_CPU(cs)->env.spr_cb[SPR_PIR].default_value & ~(cs->nr_threads - 1))
+    (POWERPC_CPU(cs)->env.core_index)
 
 #define THREAD_SIBLING_FOREACH(cs, cs_sibling)                  \
     CPU_FOREACH(cs_sibling)                                     \
diff --git a/hw/ppc/pnv_core.c b/hw/ppc/pnv_core.c
index 9b5edd9e48..0f61aabb77 100644
--- a/hw/ppc/pnv_core.c
+++ b/hw/ppc/pnv_core.c
@@ -252,6 +252,8 @@ 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 e7c9edd033..059d372c8a 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -300,16 +300,19 @@ 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.
      */
     qdev_prop_set_bit(DEVICE(obj), "start-powered-off", true);
+    env->core_index = cc->core_id;
     cs->cpu_index = cc->core_id + i;
     if (!spapr_set_vcpu_id(cpu, cs->cpu_index, errp)) {
         return NULL;
-- 
2.43.0