[Qemu-devel] [RFC 08/28] s390x/cpumodel: store the CPU model in the CPU instance

[David Hildenbrand <dahi@linux.vnet.ibm.com>]

A CPU model consists of a CPU definition, to which delta changes are
applied - features added or removed (e.g. z13-base,vx=on). In addition,
certain properties (e.g. cpu id) can later on change during migration
but belong into the CPU model. This data will later be filled from the
host model in the KVM case.

Therefore, store the configured CPU model inside the CPU instance, so
we can later on perform delta changes using properties.

For the "qemu" model, we emulate in TCG a z900. "host" will be
uninitialized (cpu->model == NULL) unless we have CPU model support in KVM
later on. The other models are all initialized from their definitions.
Only the "host" model can have a cpu->model == NULL.

Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
---
 target-s390x/cpu.h        |  1 +
 target-s390x/cpu_models.c | 26 ++++++++++++++++++++++++++
 target-s390x/cpu_models.h | 10 ++++++++++
 3 files changed, 37 insertions(+)

diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index 832da89..ec60b3b 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -187,6 +187,7 @@ struct S390CPU {
 
     CPUS390XState env;
     int64_t id;
+    S390CPUModel *model;
     /* needed for live migration */
     void *irqstate;
     uint32_t irqstate_saved_size;
diff --git a/target-s390x/cpu_models.c b/target-s390x/cpu_models.c
index 50b395a..d54b795 100644
--- a/target-s390x/cpu_models.c
+++ b/target-s390x/cpu_models.c
@@ -141,6 +141,21 @@ void s390_realize_cpu_model(CPUState *cs, Error **errp)
 
 static void s390_cpu_model_initfn(Object *obj)
 {
+    S390CPU *cpu = S390_CPU(obj);
+    S390CPUClass *xcc = S390_CPU_GET_CLASS(cpu);
+
+    cpu->model = g_malloc0(sizeof(*cpu->model));
+    /* copy the model, so we can modify it */
+    cpu->model->def = xcc->cpu_def;
+    if (xcc->migration_safe) {
+        /* base model - features will mever change */
+        bitmap_copy(cpu->model->features, cpu->model->def->base_feat,
+                    S390_FEAT_MAX);
+    } else {
+        /* latest model - features can change */
+        bitmap_copy(cpu->model->features,
+                    cpu->model->def->default_feat, S390_FEAT_MAX);
+    }
 }
 
 #ifdef CONFIG_KVM
@@ -151,10 +166,21 @@ static void s390_host_cpu_model_initfn(Object *obj)
 
 static void s390_qemu_cpu_model_initfn(Object *obj)
 {
+    S390CPU *cpu = S390_CPU(obj);
+
+    cpu->model = g_malloc0(sizeof(*cpu->model));
+    /* TCG emulates a z900 */
+    cpu->model->def = &s390_cpu_defs[0];
+    bitmap_copy(cpu->model->features, cpu->model->def->default_feat,
+                S390_FEAT_MAX);
 }
 
 static void s390_cpu_model_finalize(Object *obj)
 {
+    S390CPU *cpu = S390_CPU(obj);
+
+    g_free(cpu->model);
+    cpu->model = NULL;
 }
 
 static bool get_migratable(Object *obj, Error **errp)
diff --git a/target-s390x/cpu_models.h b/target-s390x/cpu_models.h
index 13f7217..244256b 100644
--- a/target-s390x/cpu_models.h
+++ b/target-s390x/cpu_models.h
@@ -33,4 +33,14 @@ typedef struct S390CPUDef {
     S390FeatBitmap full_feat;
 } S390CPUDef;
 
+/* CPU model based on a CPU definition */
+typedef struct S390CPUModel {
+    const S390CPUDef *def;
+    S390FeatBitmap features;
+    /* values copied from the "host" model, can change during migration */
+    uint16_t lowest_ibc;    /* lowest IBC that the hardware supports */
+    uint32_t cpu_id;        /* CPU id */
+    uint8_t cpu_ver;        /* CPU version, usually "ff" for kvm */
+} S390CPUModel;
+
 #endif /* TARGET_S390X_CPU_MODELS_H */
-- 
2.6.6