i386: Implement query-cpu-model-expansion QMP command

Implement query-cpu-model-expansion for target-i386.

This should meet all the requirements while being simple. In the
case of static expansion, it will use the new "base" CPU model,
and in the case of full expansion, it will keep the original CPU
model name+props, and append extra properties.

A future follow-up should improve the implementation of
type=full, so that it returns more detailed data, including every
writable QOM property in the CPU object.

Cc: libvir-list@redhat.com
Cc: Jiri Denemark <jdenemar@redhat.com>
Message-Id: <20170222190029.17243-3-ehabkost@redhat.com>
Tested-by: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

2 files changed, 193 insertions, 2 deletions

diff --git a/monitor.c b/monitor.c
index f8f4a07..b68944d 100644
--- a/monitor.c
+++ b/monitor.c
@@ -984,8 +984,10 @@ static void qmp_unregister_commands_hack(void)
 #ifndef TARGET_ARM
     qmp_unregister_command("query-gic-capabilities");
 #endif
-#if !defined(TARGET_S390X)
+#if !defined(TARGET_S390X) && !defined(TARGET_I386)
     qmp_unregister_command("query-cpu-model-expansion");
+#endif
+#if !defined(TARGET_S390X)
     qmp_unregister_command("query-cpu-model-baseline");
     qmp_unregister_command("query-cpu-model-comparison");
 #endif
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 0a71594..139b7ea 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -29,10 +29,16 @@
 #include "qemu/option.h"
 #include "qemu/config-file.h"
 #include "qapi/qmp/qerror.h"
+#include "qapi/qmp/qstring.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qbool.h"
+#include "qapi/qmp/qint.h"
+#include "qapi/qmp/qfloat.h"
 
 #include "qapi-types.h"
 #include "qapi-visit.h"
 #include "qapi/visitor.h"
+#include "qom/qom-qobject.h"
 #include "sysemu/arch_init.h"
 
 #if defined(CONFIG_KVM)
@@ -2288,7 +2294,7 @@ static void x86_cpu_apply_props(X86CPU *cpu, PropValue *props)
     }
 }
 
-/* Load data from X86CPUDefinition
+/* Load data from X86CPUDefinition into a X86CPU object
  */
 static void x86_cpu_load_def(X86CPU *cpu, X86CPUDefinition *def, Error **errp)
 {
@@ -2297,6 +2303,11 @@ static void x86_cpu_load_def(X86CPU *cpu, X86CPUDefinition *def, Error **errp)
     char host_vendor[CPUID_VENDOR_SZ + 1];
     FeatureWord w;
 
+    /*NOTE: any property set by this function should be returned by
+     * x86_cpu_static_props(), so static expansion of
+     * query-cpu-model-expansion is always complete.
+     */
+
     /* CPU models only set _minimum_ values for level/xlevel: */
     object_property_set_int(OBJECT(cpu), def->level, "min-level", errp);
     object_property_set_int(OBJECT(cpu), def->xlevel, "min-xlevel", errp);
@@ -2341,6 +2352,184 @@ static void x86_cpu_load_def(X86CPU *cpu, X86CPUDefinition *def, Error **errp)
 
 }
 
+/* Return a QDict containing keys for all properties that can be included
+ * in static expansion of CPU models. All properties set by x86_cpu_load_def()
+ * must be included in the dictionary.
+ */
+static QDict *x86_cpu_static_props(void)
+{
+    FeatureWord w;
+    int i;
+    static const char *props[] = {
+        "min-level",
+        "min-xlevel",
+        "family",
+        "model",
+        "stepping",
+        "model-id",
+        "vendor",
+        "lmce",
+        NULL,
+    };
+    static QDict *d;
+
+    if (d) {
+        return d;
+    }
+
+    d = qdict_new();
+    for (i = 0; props[i]; i++) {
+        qdict_put_obj(d, props[i], qnull());
+    }
+
+    for (w = 0; w < FEATURE_WORDS; w++) {
+        FeatureWordInfo *fi = &feature_word_info[w];
+        int bit;
+        for (bit = 0; bit < 32; bit++) {
+            if (!fi->feat_names[bit]) {
+                continue;
+            }
+            qdict_put_obj(d, fi->feat_names[bit], qnull());
+        }
+    }
+
+    return d;
+}
+
+/* Add an entry to @props dict, with the value for property. */
+static void x86_cpu_expand_prop(X86CPU *cpu, QDict *props, const char *prop)
+{
+    QObject *value = object_property_get_qobject(OBJECT(cpu), prop,
+                                                 &error_abort);
+
+    qdict_put_obj(props, prop, value);
+}
+
+/* Convert CPU model data from X86CPU object to a property dictionary
+ * that can recreate exactly the same CPU model.
+ */
+static void x86_cpu_to_dict(X86CPU *cpu, QDict *props)
+{
+    QDict *sprops = x86_cpu_static_props();
+    const QDictEntry *e;
+
+    for (e = qdict_first(sprops); e; e = qdict_next(sprops, e)) {
+        const char *prop = qdict_entry_key(e);
+        x86_cpu_expand_prop(cpu, props, prop);
+    }
+}
+
+static void object_apply_props(Object *obj, QDict *props, Error **errp)
+{
+    const QDictEntry *prop;
+    Error *err = NULL;
+
+    for (prop = qdict_first(props); prop; prop = qdict_next(props, prop)) {
+        object_property_set_qobject(obj, qdict_entry_value(prop),
+                                         qdict_entry_key(prop), &err);
+        if (err) {
+            break;
+        }
+    }
+
+    error_propagate(errp, err);
+}
+
+/* Create X86CPU object according to model+props specification */
+static X86CPU *x86_cpu_from_model(const char *model, QDict *props, Error **errp)
+{
+    X86CPU *xc = NULL;
+    X86CPUClass *xcc;
+    Error *err = NULL;
+
+    xcc = X86_CPU_CLASS(cpu_class_by_name(TYPE_X86_CPU, model));
+    if (xcc == NULL) {
+        error_setg(&err, "CPU model '%s' not found", model);
+        goto out;
+    }
+
+    xc = X86_CPU(object_new(object_class_get_name(OBJECT_CLASS(xcc))));
+    if (props) {
+        object_apply_props(OBJECT(xc), props, &err);
+        if (err) {
+            goto out;
+        }
+    }
+
+    x86_cpu_expand_features(xc, &err);
+    if (err) {
+        goto out;
+    }
+
+out:
+    if (err) {
+        error_propagate(errp, err);
+        object_unref(OBJECT(xc));
+        xc = NULL;
+    }
+    return xc;
+}
+
+CpuModelExpansionInfo *
+arch_query_cpu_model_expansion(CpuModelExpansionType type,
+                                                      CpuModelInfo *model,
+                                                      Error **errp)
+{
+    X86CPU *xc = NULL;
+    Error *err = NULL;
+    CpuModelExpansionInfo *ret = g_new0(CpuModelExpansionInfo, 1);
+    QDict *props = NULL;
+    const char *base_name;
+
+    xc = x86_cpu_from_model(model->name,
+                            model->has_props ?
+                                qobject_to_qdict(model->props) :
+                                NULL, &err);
+    if (err) {
+        goto out;
+    }
+
+
+    switch (type) {
+    case CPU_MODEL_EXPANSION_TYPE_STATIC:
+        /* Static expansion will be based on "base" only */
+        base_name = "base";
+    break;
+    case CPU_MODEL_EXPANSION_TYPE_FULL:
+        /* As we don't return every single property, full expansion needs
+         * to keep the original model name+props, and add extra
+         * properties on top of that.
+         */
+        base_name = model->name;
+        if (model->has_props && model->props) {
+            props = qdict_clone_shallow(qobject_to_qdict(model->props));
+        }
+    break;
+    default:
+        error_setg(&err, "Unsupportted expansion type");
+        goto out;
+    }
+
+    if (!props) {
+        props = qdict_new();
+    }
+    x86_cpu_to_dict(xc, props);
+
+    ret->model = g_new0(CpuModelInfo, 1);
+    ret->model->name = g_strdup(base_name);
+    ret->model->props = QOBJECT(props);
+    ret->model->has_props = true;
+
+out:
+    object_unref(OBJECT(xc));
+    if (err) {
+        error_propagate(errp, err);
+        qapi_free_CpuModelExpansionInfo(ret);
+        ret = NULL;
+    }
+    return ret;
+}
+
 X86CPU *cpu_x86_init(const char *cpu_model)
 {
     return X86_CPU(cpu_generic_init(TYPE_X86_CPU, cpu_model));