[Qemu-devel] [RFC 09/28] s390x/cpumodel: expose features and feature groups as properties

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

Let's add all features and feature groups as properties to all CPU models.
If the "host" CPU model is unknown, we can neither query nor change
features. KVM will just continue to work like it did until now.

We will not allow to enable features that were not part of the original
CPU model, because that could collide with the IBC in KVM.

Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
---
 target-s390x/cpu.c        |   1 +
 target-s390x/cpu.h        |   1 +
 target-s390x/cpu_models.c | 149 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 151 insertions(+)

diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
index d7d0b62..2f3c8e2 100644
--- a/target-s390x/cpu.c
+++ b/target-s390x/cpu.c
@@ -291,6 +291,7 @@ static void s390_cpu_initfn(Object *obj)
     cs->exception_index = EXCP_HLT;
     object_property_add(OBJECT(cpu), "id", "int64_t", s390x_cpu_get_id,
                         s390x_cpu_set_id, NULL, NULL, NULL);
+    s390_cpu_model_register_props(obj);
 #if !defined(CONFIG_USER_ONLY)
     qemu_get_timedate(&tm, 0);
     env->tod_offset = TOD_UNIX_EPOCH +
diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index ec60b3b..47a1861 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -633,6 +633,7 @@ extern void subsystem_reset(void);
 
 void s390_cpu_list(FILE *f, fprintf_function cpu_fprintf);
 #define cpu_list s390_cpu_list
+void s390_cpu_model_register_props(Object *obj);
 void s390_cpu_model_class_register_props(ObjectClass *oc);
 void s390_realize_cpu_model(CPUState *cs, Error **errp);
 ObjectClass *s390_cpu_class_by_name(const char *name);
diff --git a/target-s390x/cpu_models.c b/target-s390x/cpu_models.c
index d54b795..93e63cb 100644
--- a/target-s390x/cpu_models.c
+++ b/target-s390x/cpu_models.c
@@ -14,6 +14,7 @@
 #include "cpu.h"
 #include "gen-features.h"
 #include "qapi/error.h"
+#include "qapi/visitor.h"
 #ifndef CONFIG_USER_ONLY
 #include "sysemu/arch_init.h"
 #endif
@@ -96,8 +97,24 @@ void s390_cpu_list(FILE *f, fprintf_function print)
         f = f,
         print = print,
     };
+    S390FeatGroup group;
+    S390Feat feat;
 
     object_class_foreach(print_cpu_model_list, TYPE_S390_CPU, false, &info);
+
+    (*print)(f, "\nRecognized feature flags:\n");
+    for (feat = 0; feat < S390_FEAT_MAX; feat++) {
+        const S390FeatDef *def = s390_feat_def(feat);
+
+        (*print)(f, "%-20s %-50s\n", def->name, def->desc);
+    }
+
+    (*print)(f, "\nRecognized feature groups:\n");
+    for (group = 0; group < S390_FEAT_GROUP_MAX; group++) {
+        const S390FeatGroupDef *def = s390_feat_group_def(group);
+
+        (*print)(f, "%-20s %-50s\n", def->name, def->desc);
+    }
 }
 
 #ifndef CONFIG_USER_ONLY
@@ -139,6 +156,138 @@ void s390_realize_cpu_model(CPUState *cs, Error **errp)
     }
 }
 
+static void get_feature(Object *obj, Visitor *v, const char *name,
+                        void *opaque, Error **errp)
+{
+    S390Feat feat = (S390Feat) opaque;
+    S390CPU *cpu = S390_CPU(obj);
+    bool value;
+
+    if (!cpu->model) {
+        error_setg(errp, "Details about the host CPU model are not available, "
+                         "features cannot be queried.");
+        return;
+    }
+
+    value = test_bit(feat, cpu->model->features);
+    visit_type_bool(v, name, &value, errp);
+}
+
+static void set_feature(Object *obj, Visitor *v, const char *name,
+                        void *opaque, Error **errp)
+{
+    S390Feat feat = (S390Feat) opaque;
+    DeviceState *dev = DEVICE(obj);
+    S390CPU *cpu = S390_CPU(obj);
+    bool value;
+
+    if (dev->realized) {
+        error_setg(errp, "Attempt to set property '%s' on '%s' after "
+                   "it was realized", name, object_get_typename(obj));
+        return;
+    } else if (!cpu->model) {
+        error_setg(errp, "Details about the host CPU model are not available, "
+                         "features cannot be changed.");
+        return;
+    }
+
+    visit_type_bool(v, name, &value, errp);
+    if (*errp) {
+        return;
+    }
+    if (value) {
+        if (!test_bit(feat, cpu->model->def->full_feat)) {
+            error_setg(errp, "Feature '%s' is not available for CPU model '%s',"
+                       " it was introduced with later models.",
+                       name, cpu->model->def->name);
+            return;
+        }
+        set_bit(feat, cpu->model->features);
+    } else {
+        clear_bit(feat, cpu->model->features);
+    }
+}
+
+static void get_feature_group(Object *obj, Visitor *v, const char *name,
+                              void *opaque, Error **errp)
+{
+    S390FeatGroup group = (S390FeatGroup) opaque;
+    const S390FeatGroupDef *def = s390_feat_group_def(group);
+    S390CPU *cpu = S390_CPU(obj);
+    S390FeatBitmap tmp;
+    bool value;
+
+    if (!cpu->model) {
+        error_setg(errp, "Details about the host CPU model are not available, "
+                         "features cannot be queried.");
+        return;
+    }
+
+    /* a group is enabled if all features are enabled */
+    bitmap_and(tmp, cpu->model->features, def->feat, S390_FEAT_MAX);
+    value = bitmap_equal(tmp, def->feat, S390_FEAT_MAX);
+    visit_type_bool(v, name, &value, errp);
+}
+
+static void set_feature_group(Object *obj, Visitor *v, const char *name,
+                              void *opaque, Error **errp)
+{
+    S390FeatGroup group = (S390FeatGroup) opaque;
+    const S390FeatGroupDef *def = s390_feat_group_def(group);
+    DeviceState *dev = DEVICE(obj);
+    S390CPU *cpu = S390_CPU(obj);
+    bool value;
+
+    if (dev->realized) {
+        error_setg(errp, "Attempt to set property '%s' on '%s' after "
+                   "it was realized", name, object_get_typename(obj));
+        return;
+    } else if (!cpu->model) {
+        error_setg(errp, "Details about the host CPU model are not available, "
+                         "features cannot be changed.");
+        return;
+    }
+
+    visit_type_bool(v, name, &value, errp);
+    if (*errp) {
+        return;
+    }
+    if (value) {
+        /* groups are added in one shot, so an intersect is sufficient */
+        if (!bitmap_intersects(def->feat, cpu->model->def->full_feat,
+                               S390_FEAT_MAX)) {
+            error_setg(errp, "Group '%s' is not available for CPU model '%s',"
+                       " it was introduced with later models.",
+                       name, cpu->model->def->name);
+            return;
+        }
+        bitmap_or(cpu->model->features, cpu->model->features, def->feat,
+                  S390_FEAT_MAX);
+    } else {
+        bitmap_andnot(cpu->model->features, cpu->model->features, def->feat,
+                      S390_FEAT_MAX);
+    }
+}
+
+void s390_cpu_model_register_props(Object *obj)
+{
+    S390FeatGroup group;
+    S390Feat feat;
+
+    for (feat = 0; feat < S390_FEAT_MAX; feat++) {
+        const S390FeatDef *def = s390_feat_def(feat);
+        object_property_add(obj, def->name, "bool", get_feature,
+                            set_feature, NULL, (void *) feat, NULL);
+        object_property_set_description(obj, def->name, def->desc , NULL);
+    }
+    for (group = 0; group < S390_FEAT_GROUP_MAX; group++) {
+        const S390FeatGroupDef *def = s390_feat_group_def(group);
+        object_property_add(obj, def->name, "bool", get_feature_group,
+                            set_feature_group, NULL, (void *) group, NULL);
+        object_property_set_description(obj, def->name, def->desc , NULL);
+    }
+}
+
 static void s390_cpu_model_initfn(Object *obj)
 {
     S390CPU *cpu = S390_CPU(obj);
-- 
2.6.6