cpu: Use CPUClass->parse_features() as convertor to global properties

Currently CPUClass->parse_features() is used to parse -cpu
features string and set properties on created CPU instances.

But considering that features specified by -cpu apply to every
created CPU instance, it doesn't make sense to parse the same
features string for every CPU created. It also makes every target
that cares about parsing features string explicitly call
CPUClass->parse_features() parser, which gets in a way if we
consider using generic device_add for CPU hotplug as device_add
has not a clue about CPU specific hooks.

Turns out we can use global properties mechanism to set
properties on every created CPU instance for a given type. That
way it's possible to convert CPU features into a set of global
properties for CPU type specified by -cpu cpu_model and common
Device.device_post_init() will apply them to CPU of given type
automatically regardless whether it's manually created CPU or CPU
created with help of device_add.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

4 files changed, 54 insertions, 22 deletions

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 6e098afd1f..ae90ca5771 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1261,6 +1261,7 @@ static void machvirt_init(MachineState *machine)
 
     for (n = 0; n < smp_cpus; n++) {
         ObjectClass *oc = cpu_class_by_name(TYPE_ARM_CPU, cpustr[0]);
+        const char *typename = object_class_get_name(oc);
         CPUClass *cc = CPU_CLASS(oc);
         Object *cpuobj;
         Error *err = NULL;
@@ -1270,10 +1271,10 @@ static void machvirt_init(MachineState *machine)
             error_report("Unable to find CPU definition");
             exit(1);
         }
-        cpuobj = object_new(object_class_get_name(oc));
+        /* convert -smp CPU options specified by the user into global props */
+        cc->parse_features(typename, cpuopts, &err);
+        cpuobj = object_new(typename);
 
-        /* Handle any CPU options specified by the user */
-        cc->parse_features(CPU(cpuobj), cpuopts, &err);
         g_free(cpuopts);
         if (err) {
             error_report_err(err);
diff --git a/include/qom/cpu.h b/include/qom/cpu.h
index 32f3af3e1c..cacb100f7b 100644
--- a/include/qom/cpu.h
+++ b/include/qom/cpu.h
@@ -134,7 +134,7 @@ typedef struct CPUClass {
     /*< public >*/
 
     ObjectClass *(*class_by_name)(const char *cpu_model);
-    void (*parse_features)(CPUState *cpu, char *str, Error **errp);
+    void (*parse_features)(const char *typename, char *str, Error **errp);
 
     void (*reset)(CPUState *cpu);
     int reset_dump_flags;
diff --git a/qom/cpu.c b/qom/cpu.c
index 751e992de8..2a0d9fe10f 100644
--- a/qom/cpu.c
+++ b/qom/cpu.c
@@ -28,6 +28,7 @@
 #include "exec/log.h"
 #include "qemu/error-report.h"
 #include "sysemu/sysemu.h"
+#include "hw/qdev-properties.h"
 
 bool cpu_exists(int64_t id)
 {
@@ -46,7 +47,7 @@ bool cpu_exists(int64_t id)
 CPUState *cpu_generic_init(const char *typename, const char *cpu_model)
 {
     char *str, *name, *featurestr;
-    CPUState *cpu;
+    CPUState *cpu = NULL;
     ObjectClass *oc;
     CPUClass *cc;
     Error *err = NULL;
@@ -60,16 +61,18 @@ CPUState *cpu_generic_init(const char *typename, const char *cpu_model)
         return NULL;
     }
 
-    cpu = CPU(object_new(object_class_get_name(oc)));
-    cc = CPU_GET_CLASS(cpu);
-
+    cc = CPU_CLASS(oc);
     featurestr = strtok(NULL, ",");
-    cc->parse_features(cpu, featurestr, &err);
+    /* TODO: all callers of cpu_generic_init() need to be converted to
+     * call parse_features() only once, before calling cpu_generic_init().
+     */
+    cc->parse_features(object_class_get_name(oc), featurestr, &err);
     g_free(str);
     if (err != NULL) {
         goto out;
     }
 
+    cpu = CPU(object_new(object_class_get_name(oc)));
     object_property_set_bool(OBJECT(cpu), true, "realized", &err);
 
 out:
@@ -282,25 +285,39 @@ static ObjectClass *cpu_common_class_by_name(const char *cpu_model)
     return NULL;
 }
 
-static void cpu_common_parse_features(CPUState *cpu, char *features,
+static void cpu_common_parse_features(const char *typename, char *features,
                                       Error **errp)
 {
     char *featurestr; /* Single "key=value" string being parsed */
     char *val;
-    Error *err = NULL;
+    static bool cpu_globals_initialized;
+
+    /* TODO: all callers of ->parse_features() need to be changed to
+     * call it only once, so we can remove this check (or change it
+     * to assert(!cpu_globals_initialized).
+     * Current callers of ->parse_features() are:
+     * - machvirt_init()
+     * - cpu_generic_init()
+     * - cpu_x86_create()
+     */
+    if (cpu_globals_initialized) {
+        return;
+    }
+    cpu_globals_initialized = true;
 
     featurestr = features ? strtok(features, ",") : NULL;
 
     while (featurestr) {
         val = strchr(featurestr, '=');
         if (val) {
+            GlobalProperty *prop = g_new0(typeof(*prop), 1);
             *val = 0;
             val++;
-            object_property_parse(OBJECT(cpu), val, featurestr, &err);
-            if (err) {
-                error_propagate(errp, err);
-                return;
-            }
+            prop->driver = typename;
+            prop->property = g_strdup(featurestr);
+            prop->value = g_strdup(val);
+            prop->errp = &error_fatal;
+            qdev_prop_register_global(prop);
         } else {
             error_setg(errp, "Expected key=value format, found %s.",
                        featurestr);
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 0b286e161c..16977d5404 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -1958,12 +1958,17 @@ static FeatureWordArray minus_features = { 0 };
 
 /* Parse "+feature,-feature,feature=foo" CPU feature string
  */
-static void x86_cpu_parse_featurestr(CPUState *cs, char *features,
+static void x86_cpu_parse_featurestr(const char *typename, char *features,
                                      Error **errp)
 {
-    X86CPU *cpu = X86_CPU(cs);
     char *featurestr; /* Single 'key=value" string being parsed */
     Error *local_err = NULL;
+    static bool cpu_globals_initialized;
+
+    if (cpu_globals_initialized) {
+        return;
+    }
+    cpu_globals_initialized = true;
 
     if (!features) {
         return;
@@ -1976,6 +1981,7 @@ static void x86_cpu_parse_featurestr(CPUState *cs, char *features,
         const char *val = NULL;
         char *eq = NULL;
         char num[32];
+        GlobalProperty *prop;
 
         /* Compatibility syntax: */
         if (featurestr[0] == '+') {
@@ -2013,7 +2019,12 @@ static void x86_cpu_parse_featurestr(CPUState *cs, char *features,
             name = "tsc-frequency";
         }
 
-        object_property_parse(OBJECT(cpu), val, name, &local_err);
+        prop = g_new0(typeof(*prop), 1);
+        prop->driver = typename;
+        prop->property = g_strdup(name);
+        prop->value = g_strdup(val);
+        prop->errp = &error_fatal;
+        qdev_prop_register_global(prop);
     }
 
     if (local_err) {
@@ -2202,9 +2213,11 @@ X86CPU *cpu_x86_create(const char *cpu_model, Error **errp)
 {
     X86CPU *cpu = NULL;
     ObjectClass *oc;
+    CPUClass *cc;
     gchar **model_pieces;
     char *name, *features;
     Error *error = NULL;
+    const char *typename;
 
     model_pieces = g_strsplit(cpu_model, ",", 2);
     if (!model_pieces[0]) {
@@ -2219,10 +2232,11 @@ X86CPU *cpu_x86_create(const char *cpu_model, Error **errp)
         error_setg(&error, "Unable to find CPU definition: %s", name);
         goto out;
     }
+    cc = CPU_CLASS(oc);
+    typename = object_class_get_name(oc);
 
-    cpu = X86_CPU(object_new(object_class_get_name(oc)));
-
-    x86_cpu_parse_featurestr(CPU(cpu), features, &error);
+    cc->parse_features(typename, features, &error);
+    cpu = X86_CPU(object_new(typename));
     if (error) {
         goto out;
     }