[Qemu-devel] [RFC 7/7] target-i386: CPU model subclasses

[Eduardo Habkost]

Register separate QOM classes for each x86 CPU model.

This will allow management code to more easily probe what each CPU model
provides, by simply creating objects using the appropriate class name,
without having to restart QEMU.

This also allows us to eliminate the qdev_prop_set_globals_for_type()
hack to set CPU-model-specific global properties.

Instead of creating separate class_init functions for each class, I just
used class_dat to store a pointer to the X86CPUDefinition struct for
each CPU model. This should make the patch shorter and easier to review.
Later we can gradually convert each X86CPUDefinition field to lists of
per-class property defaults.

Signed-off-by: Eduardo Habkost <address@hidden>
---
This version is closer to the version sent by Andrea and then later
resubmitted by Igor as "[RFC v5] target-i386: Slim conversion to X86CPU
subclasses + KVM subclasses", as it doesn't create one new class_init
function for each subclass. One main difference is that this version
does not use KVM-specific subclasses, to keep things simpler.
---
 target-i386/cpu-qom.h |  13 ++
 target-i386/cpu.c     | 343 +++++++++++++++++++++++++++++++-------------------
 target-i386/cpu.h     |   2 -
 3 files changed, 228 insertions(+), 130 deletions(-)

diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h
index f4fab15..468fea7 100644
--- a/target-i386/cpu-qom.h
+++ b/target-i386/cpu-qom.h
@@ -37,6 +37,9 @@
 #define X86_CPU_GET_CLASS(obj) \
     OBJECT_GET_CLASS(X86CPUClass, (obj), TYPE_X86_CPU)
 
+
+typedef struct X86CPUDefinition X86CPUDefinition;
+
 /**
  * X86CPUClass:
  * @parent_realize: The parent class' realize handler.
@@ -49,6 +52,16 @@ typedef struct X86CPUClass {
     CPUClass parent_class;
     /*< public >*/
 
+    /* CPU model definition
+     * Should be eventually replaced by subclass-specific property defaults
+     */
+    X86CPUDefinition *cpu_def;
+    /* CPU model requires KVM to be enabled */
+    bool kvm_required;
+    /* Optional description of CPU model.
+     * If unavailable, cpu_def->model_id is used */
+    const char *model_description;
+
     DeviceRealize parent_realize;
     void (*parent_reset)(CPUState *cpu);
 } X86CPUClass;
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index ab80081..5898d52 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -481,7 +481,10 @@ static void add_flagname_to_bitmaps(const char *flagname,
     }
 }
 
-typedef struct X86CPUDefinition {
+/* CPU model definition data that was not converted to QOM per-subclass
+ * property defaults yet.
+ */
+struct X86CPUDefinition {
     const char *name;
     uint32_t level;
     uint32_t xlevel;
@@ -494,7 +497,7 @@ typedef struct X86CPUDefinition {
     FeatureWordArray features;
     char model_id[48];
     bool cache_info_passthrough;
-} X86CPUDefinition;
+};
 
 #define I486_FEATURES (CPUID_FP87 | CPUID_VME | CPUID_PSE)
 #define PENTIUM_FEATURES (I486_FEATURES | CPUID_DE | CPUID_TSC | \
@@ -544,8 +547,41 @@ typedef struct X86CPUDefinition {
           CPUID_7_0_EBX_ERMS, CPUID_7_0_EBX_INVPCID, CPUID_7_0_EBX_RTM,
           CPUID_7_0_EBX_RDSEED */
 
-/* built-in CPU model definitions
+/* CPU class name definitions: */
+
+#define X86_CPU_CLASS_SUFFIX "-" TYPE_X86_CPU
+#define CPU_CLASS_NAME(name) (name X86_CPU_CLASS_SUFFIX)
+
+
+static char *x86_cpu_class_get_model_name(X86CPUClass *cc)
+{
+    const char *class_name = object_class_get_name(OBJECT_CLASS(cc));
+    if (g_str_has_suffix(class_name, X86_CPU_CLASS_SUFFIX)) {
+        return g_strndup(class_name,
+                         strlen(class_name) - strlen(X86_CPU_CLASS_SUFFIX));
+    } else {
+        return g_strdup(class_name);
+    }
+}
+
+/* Return class name for a given CPU model name
+ * Caller is responsible for freeing the returned string.
  */
+static char *x86_cpu_class_name(const char *model_name)
+{
+    return g_strdup_printf(CPU_CLASS_NAME("%s"), model_name);
+}
+
+/* Return X86CPUClass for a CPU model name */
+static X86CPUClass *x86_cpu_class_by_name(const char *name)
+{
+    X86CPUClass *cc;
+    char *class_name = x86_cpu_class_name(name);
+    cc =  X86_CPU_CLASS(object_class_by_name(class_name));
+    g_free(class_name);
+    return cc;
+}
+
 static X86CPUDefinition builtin_x86_defs[] = {
     {
         .name = "qemu64",
@@ -1090,6 +1126,33 @@ static X86CPUDefinition builtin_x86_defs[] = {
     },
 };
 
+static void x86_cpu_class_init_cpudef(ObjectClass *oc, void *data)
+{
+    X86CPUDefinition *cpudef = data;
+    X86CPUClass *xcc = X86_CPU_CLASS(oc);
+    xcc->cpu_def = cpudef;
+}
+
+static void x86_register_cpudef_classes(void)
+{
+    int i;
+    for (i = 0; i < ARRAY_SIZE(builtin_x86_defs); i++) {
+        X86CPUDefinition *def = &builtin_x86_defs[i];
+        char *class_name = x86_cpu_class_name(def->name);
+        TypeInfo ti = {
+            .name = class_name,
+            .parent = TYPE_X86_CPU,
+            .instance_size = sizeof(X86CPU),
+            .abstract = false,
+            .class_size = sizeof(X86CPUClass),
+            .class_init = x86_cpu_class_init_cpudef,
+            .class_data = def,
+        };
+        type_register(&ti);
+        g_free(class_name);
+    }
+}
+
 /**
  * x86_cpu_compat_set_features:
  * @cpu_model: CPU model name to be changed. If NULL, all CPU models are 
changed
@@ -1131,44 +1194,77 @@ static int cpu_x86_fill_model_id(char *str)
     return 0;
 }
 
-/* Fill a X86CPUDefinition struct with information about the host CPU, and
- * the CPU features supported by the host hardware + host kernel
+static X86CPUDefinition host_cpudef;
+
+/* class_init for the "host" CPU model
  *
- * This function may be called only if KVM is enabled.
+ * This function may be called before KVM is initialized.
  */
-static void kvm_cpu_fill_host(X86CPUDefinition *x86_cpu_def)
+static void x86_cpu_class_init_host(ObjectClass *oc, void *data)
 {
-    KVMState *s = kvm_state;
+    X86CPUClass *xcc = X86_CPU_CLASS(oc);
     uint32_t eax = 0, ebx = 0, ecx = 0, edx = 0;
 
-    assert(kvm_enabled());
+    xcc->kvm_required = true;
 
-    x86_cpu_def->name = "host";
-    x86_cpu_def->cache_info_passthrough = true;
     host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
-    x86_cpu_vendor_words2str(x86_cpu_def->vendor, ebx, edx, ecx);
+    x86_cpu_vendor_words2str(host_cpudef.vendor, ebx, edx, ecx);
 
     host_cpuid(0x1, 0, &eax, &ebx, &ecx, &edx);
-    x86_cpu_def->family = ((eax >> 8) & 0x0F) + ((eax >> 20) & 0xFF);
-    x86_cpu_def->model = ((eax >> 4) & 0x0F) | ((eax & 0xF0000) >> 12);
-    x86_cpu_def->stepping = eax & 0x0F;
+    host_cpudef.family = ((eax >> 8) & 0x0F) + ((eax >> 20) & 0xFF);
+    host_cpudef.model = ((eax >> 4) & 0x0F) | ((eax & 0xF0000) >> 12);
+    host_cpudef.stepping = eax & 0x0F;
 
-    x86_cpu_def->level = kvm_arch_get_supported_cpuid(s, 0x0, 0, R_EAX);
-    x86_cpu_def->xlevel = kvm_arch_get_supported_cpuid(s, 0x80000000, 0, 
R_EAX);
-    x86_cpu_def->xlevel2 =
-        kvm_arch_get_supported_cpuid(s, 0xC0000000, 0, R_EAX);
+    cpu_x86_fill_model_id(host_cpudef.model_id);
 
-    cpu_x86_fill_model_id(x86_cpu_def->model_id);
+    xcc->cpu_def = &host_cpudef;
+    xcc->model_description =
+        "KVM processor with all supported host features "
+        "(only available in KVM mode)";
+
+    host_cpudef.cache_info_passthrough = true;
+
+    /* level, xlevel, xlevel2, and the feature words are initialized on
+     * instance_init, because they require KVM to be initialized.
+     */
+}
+
+static void x86_cpu_instance_init_host(Object *obj)
+{
+    X86CPU *cpu = X86_CPU(obj);
+    CPUX86State *env = &cpu->env;
+    KVMState *s = kvm_state;
+    Error *err = NULL;
+
+    assert(kvm_enabled());
+
+    env->cpuid_level = kvm_arch_get_supported_cpuid(s, 0x0, 0, R_EAX);
+    env->cpuid_xlevel = kvm_arch_get_supported_cpuid(s, 0x80000000, 0, R_EAX);
+    env->cpuid_xlevel2 = kvm_arch_get_supported_cpuid(s, 0xC0000000, 0, R_EAX);
 
     FeatureWord w;
     for (w = 0; w < FEATURE_WORDS; w++) {
         FeatureWordInfo *wi = &feature_word_info[w];
-        x86_cpu_def->features[w] =
+        env->features[w] =
             kvm_arch_get_supported_cpuid(s, wi->cpuid_eax, wi->cpuid_ecx,
                                          wi->cpuid_reg);
     }
+    object_property_set_bool(OBJECT(cpu), true, "pmu", &err);
+
+    assert_no_error(err);
 }
 
+
+static const TypeInfo x86_cpu_host_type_info = {
+    .name = CPU_CLASS_NAME("host"),
+    .parent = TYPE_X86_CPU,
+    .instance_size = sizeof(X86CPU),
+    .instance_init = x86_cpu_instance_init_host,
+    .abstract = false,
+    .class_size = sizeof(X86CPUClass),
+    .class_init = x86_cpu_class_init_host,
+};
+
 static int unavailable_host_feature(FeatureWordInfo *f, uint32_t mask)
 {
     int i;
@@ -1539,34 +1635,6 @@ static void x86_cpu_get_feature_words(Object *obj, 
Visitor *v, void *opaque,
     error_propagate(errp, err);
 }
 
-static int cpu_x86_find_by_name(X86CPU *cpu, X86CPUDefinition *x86_cpu_def,
-                                const char *name)
-{
-    X86CPUDefinition *def;
-    Error *err = NULL;
-    int i;
-
-    if (name == NULL) {
-        return -1;
-    }
-    if (kvm_enabled() && strcmp(name, "host") == 0) {
-        kvm_cpu_fill_host(x86_cpu_def);
-        object_property_set_bool(OBJECT(cpu), true, "pmu", &err);
-        assert_no_error(err);
-        return 0;
-    }
-
-    for (i = 0; i < ARRAY_SIZE(builtin_x86_defs); i++) {
-        def = &builtin_x86_defs[i];
-        if (strcmp(name, def->name) == 0) {
-            memcpy(x86_cpu_def, def, sizeof(*def));
-            return 0;
-        }
-    }
-
-    return -1;
-}
-
 /* Convert all '_' in a feature string option name to '-', to make feature
  * name conform to QOM property naming rule, which uses '-' instead of '_'.
  */
@@ -1729,23 +1797,63 @@ static void listflags(char *buf, int bufsize, uint32_t 
fbits,
         }
 }
 
-/* generate CPU information. */
+/* Sort alphabetically by type name, listing kvm_required models last. */
+static gint x86_cpu_list_compare(gconstpointer a, gconstpointer b)
+{
+    ObjectClass *class_a = (ObjectClass *)a;
+    ObjectClass *class_b = (ObjectClass *)b;
+    X86CPUClass *cc_a = X86_CPU_CLASS(class_a);
+    X86CPUClass *cc_b = X86_CPU_CLASS(class_b);
+    const char *name_a, *name_b;
+
+    if (cc_a->kvm_required != cc_b->kvm_required) {
+        /* kvm_required items go last */
+        return cc_a->kvm_required ? 1 : -1;
+    } else {
+        name_a = object_class_get_name(class_a);
+        name_b = object_class_get_name(class_b);
+        return strcmp(name_a, name_b);
+    }
+}
+
+static GSList *get_sorted_cpu_model_list(void)
+{
+    GSList *list = object_class_get_list(TYPE_X86_CPU, false);
+    list = g_slist_sort(list, x86_cpu_list_compare);
+    return list;
+}
+
+static void x86_cpu_list_entry(gpointer data, gpointer user_data)
+{
+    ObjectClass *oc = data;
+    X86CPUClass *cc = X86_CPU_CLASS(oc);
+    CPUListState *s = user_data;
+    char *name = x86_cpu_class_get_model_name(cc);
+    const char *desc = cc->model_description;
+    if (!desc) {
+        desc = cc->cpu_def->model_id;
+    }
+
+    (*s->cpu_fprintf)(s->file, "x86 %16s  %-48s\n",
+                      name, desc);
+    g_free(name);
+}
+
+/* list available CPU models and flags */
 void x86_cpu_list(FILE *f, fprintf_function cpu_fprintf)
 {
-    X86CPUDefinition *def;
-    char buf[256];
     int i;
+    CPUListState s = {
+        .file = f,
+        .cpu_fprintf = cpu_fprintf,
+    };
+    GSList *list;
+    char buf[256];
 
-    for (i = 0; i < ARRAY_SIZE(builtin_x86_defs); i++) {
-        def = &builtin_x86_defs[i];
-        snprintf(buf, sizeof(buf), "%s", def->name);
-        (*cpu_fprintf)(f, "x86 %16s  %-48s\n", buf, def->model_id);
-    }
-#ifdef CONFIG_KVM
-    (*cpu_fprintf)(f, "x86 %16s  %-48s\n", "host",
-                   "KVM processor with all supported host features "
-                   "(only available in KVM mode)");
-#endif
+    (*cpu_fprintf)(f, "Available CPUs:\n");
+    list = get_sorted_cpu_model_list();
+    g_slist_foreach(list, x86_cpu_list_entry, &s);
+    g_slist_free(list);
 
     (*cpu_fprintf)(f, "\nRecognized CPUID flags:\n");
     for (i = 0; i < ARRAY_SIZE(feature_word_info); i++) {
@@ -1756,26 +1864,29 @@ void x86_cpu_list(FILE *f, fprintf_function cpu_fprintf)
     }
 }
 
+static void x86_cpu_definition_entry(gpointer data, gpointer user_data)
+{
+    ObjectClass *oc = data;
+    X86CPUClass *cc = X86_CPU_CLASS(oc);
+    CpuDefinitionInfoList **cpu_list = user_data;
+    CpuDefinitionInfoList *entry;
+    CpuDefinitionInfo *info;
+
+    info = g_malloc0(sizeof(*info));
+    info->name = x86_cpu_class_get_model_name(cc);
+
+    entry = g_malloc0(sizeof(*entry));
+    entry->value = info;
+    entry->next = *cpu_list;
+    *cpu_list = entry;
+}
+
 CpuDefinitionInfoList *arch_query_cpu_definitions(Error **errp)
 {
     CpuDefinitionInfoList *cpu_list = NULL;
-    X86CPUDefinition *def;
-    int i;
-
-    for (i = 0; i < ARRAY_SIZE(builtin_x86_defs); i++) {
-        CpuDefinitionInfoList *entry;
-        CpuDefinitionInfo *info;
-
-        def = &builtin_x86_defs[i];
-        info = g_malloc0(sizeof(*info));
-        info->name = g_strdup(def->name);
-
-        entry = g_malloc0(sizeof(*entry));
-        entry->value = info;
-        entry->next = cpu_list;
-        cpu_list = entry;
-    }
-
+    GSList *list = get_sorted_cpu_model_list();
+    g_slist_foreach(list, x86_cpu_definition_entry, &cpu_list);
+    g_slist_free(list);
     return cpu_list;
 }
 
@@ -1798,19 +1909,11 @@ static void filter_features_for_kvm(X86CPU *cpu)
     }
 }
 
-/* Load CPU definition for a given CPU model name
+/* Load data from X86CPUDefinition
  */
-static void x86_cpu_load_def(X86CPU *cpu, const char *name, Error **errp)
+static void x86_cpu_load_def(X86CPU *cpu, X86CPUDefinition *def, Error **errp)
 {
     CPUX86State *env = &cpu->env;
-    X86CPUDefinition def1, *def = &def1;
-
-    memset(def, 0, sizeof(*def));
-
-    if (cpu_x86_find_by_name(cpu, def, name) < 0) {
-        error_setg(errp, "Unable to find CPU definition: %s", name);
-        return;
-    }
 
     object_property_set_int(OBJECT(cpu), def->level, "level", errp);
     object_property_set_int(OBJECT(cpu), def->family, "family", errp);
@@ -1862,7 +1965,6 @@ X86CPU *cpu_x86_create(const char *cpu_model, DeviceState 
*icc_bridge,
     X86CPU *cpu = NULL;
     gchar **model_pieces;
     char *name, *features;
-    char *typename;
     Error *error = NULL;
 
     model_pieces = g_strsplit(cpu_model, ",", 2);
@@ -1873,12 +1975,19 @@ X86CPU *cpu_x86_create(const char *cpu_model, 
DeviceState *icc_bridge,
     name = model_pieces[0];
     features = model_pieces[1];
 
-    cpu = X86_CPU(object_new(TYPE_X86_CPU));
-    x86_cpu_load_def(cpu, name, &error);
-    if (error) {
+    X86CPUClass *cc = x86_cpu_class_by_name(name);
+    if (!cc) {
+        error_setg(&error, "Unable to find CPU definition: %s", name);
+        goto out;
+     }
+
+    if (cc->kvm_required && !kvm_enabled()) {
+        error_setg(&error, "CPU model '%s' requires KVM", name);
         goto out;
     }
 
+    cpu = X86_CPU(object_new(object_class_get_name(OBJECT_CLASS(cc))));
+
 #ifndef CONFIG_USER_ONLY
     if (icc_bridge == NULL) {
         error_setg(&error, "Invalid icc-bridge value");
@@ -1888,14 +1997,6 @@ X86CPU *cpu_x86_create(const char *cpu_model, 
DeviceState *icc_bridge,
     object_unref(OBJECT(cpu));
 #endif
 
-    /* Emulate per-model subclasses for global properties */
-    typename = g_strdup_printf("%s-" TYPE_X86_CPU, name);
-    qdev_prop_set_globals_for_type(DEVICE(cpu), typename, &error);
-    g_free(typename);
-    if (error) {
-        goto out;
-    }
-
     cpu_x86_parse_featurestr(cpu, features, &error);
     if (error) {
         goto out;
@@ -1904,8 +2005,10 @@ X86CPU *cpu_x86_create(const char *cpu_model, 
DeviceState *icc_bridge,
 out:
     if (error != NULL) {
         error_propagate(errp, error);
-        object_unref(OBJECT(cpu));
-        cpu = NULL;
+        if (cpu) {
+            object_unref(OBJECT(cpu));
+            cpu = NULL;
+        }
     }
     g_strfreev(model_pieces);
     return cpu;
@@ -1944,30 +2047,6 @@ void cpu_clear_apic_feature(CPUX86State *env)
 
 #endif /* !CONFIG_USER_ONLY */
 
-/* Initialize list of CPU models, filling some non-static fields if necessary
- */
-void x86_cpudef_setup(void)
-{
-    int i, j;
-    static const char *model_with_versions[] = { "qemu32", "qemu64", "athlon" 
};
-
-    for (i = 0; i < ARRAY_SIZE(builtin_x86_defs); ++i) {
-        X86CPUDefinition *def = &builtin_x86_defs[i];
-
-        /* Look for specific "cpudef" models that */
-        /* have the QEMU version in .model_id */
-        for (j = 0; j < ARRAY_SIZE(model_with_versions); j++) {
-            if (strcmp(model_with_versions[j], def->name) == 0) {
-                pstrcpy(def->model_id, sizeof(def->model_id),
-                        "QEMU Virtual CPU version ");
-                pstrcat(def->model_id, sizeof(def->model_id),
-                        qemu_get_version());
-                break;
-            }
-        }
-    }
-}
-
 static void get_cpuid_vendor(CPUX86State *env, uint32_t *ebx,
                              uint32_t *ecx, uint32_t *edx)
 {
@@ -2595,6 +2674,7 @@ static void x86_cpu_initfn(Object *obj)
 {
     CPUState *cs = CPU(obj);
     X86CPU *cpu = X86_CPU(obj);
+    X86CPUClass *xcc = X86_CPU_GET_CLASS(cpu);
     CPUX86State *env = &cpu->env;
     static int inited;
 
@@ -2646,6 +2726,11 @@ static void x86_cpu_initfn(Object *obj)
         cpu_set_debug_excp_handler(breakpoint_handler);
 #endif
     }
+
+    X86CPUDefinition *def = xcc->cpu_def;
+    Error *err = NULL;
+    x86_cpu_load_def(cpu, def, &err);
+    assert_no_error(err);
 }
 
 static int64_t x86_cpu_get_arch_id(CPUState *cs)
@@ -2722,7 +2807,7 @@ static const TypeInfo x86_cpu_type_info = {
     .parent = TYPE_CPU,
     .instance_size = sizeof(X86CPU),
     .instance_init = x86_cpu_initfn,
-    .abstract = false,
+    .abstract = true,
     .class_size = sizeof(X86CPUClass),
     .class_init = x86_cpu_common_class_init,
 };
@@ -2730,6 +2815,8 @@ static const TypeInfo x86_cpu_type_info = {
 static void x86_cpu_register_types(void)
 {
     type_register_static(&x86_cpu_type_info);
+    x86_register_cpudef_classes();
+    type_register_static(&x86_cpu_host_type_info);
 }
 
 type_init(x86_cpu_register_types)
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index ea373e8..ea21ff3 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -925,7 +925,6 @@ X86CPU *cpu_x86_create(const char *cpu_model, DeviceState 
*icc_bridge,
                        Error **errp);
 int cpu_x86_exec(CPUX86State *s);
 void x86_cpu_list(FILE *f, fprintf_function cpu_fprintf);
-void x86_cpudef_setup(void);
 int cpu_x86_support_mca_broadcast(CPUX86State *env);
 
 int cpu_get_pic_interrupt(CPUX86State *s);
@@ -1118,7 +1117,6 @@ static inline CPUX86State *cpu_init(const char *cpu_model)
 #define cpu_gen_code cpu_x86_gen_code
 #define cpu_signal_handler cpu_x86_signal_handler
 #define cpu_list x86_cpu_list
-#define cpudef_setup x86_cpudef_setup
 
 /* MMU modes definitions */
 #define MMU_MODE0_SUFFIX _kernel
-- 
1.8.3.1