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[libvirt] [uq/master PATCH 7/7 v8] target-i386: CPU model subclasses



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_data 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.

Written based on the ideas from the patch "[RFC v5] target-i386: Slim
conversion to X86CPU subclasses + KVM subclasses" written by Andreas
Färber <afaerber suse de>, Igor Mammedov <imammedo redhat com>.

The "host" CPU model is special, as the feature flags depend on KVM
being initialized. So it has its own class_init and instance_init
function, and feature flags are set on instance_init instead of
class_init.

Signed-off-by: Andreas Färber <afaerber suse de>
Signed-off-by: Igor Mammedov <imammedo redhat com>
Signed-off-by: Eduardo Habkost <ehabkost redhat com>
---
This patch is similar to the one 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.

Main differences v5 -> v6 are:
 * Code was written from scratch (instead of using the previous patches
   as base)
   * I didn't mean to rewrite it entirely, but when doing additional
     simplification of the CPU init logic on other patches, I ended up
     rewriting it.
   * I chose to keep the Signed-off-by lines because I built upon
     Andreas's and Igor's ideas. Is that OK?
 * No KVM-specific subclasses, to keep things simpler.
 * No embedding of X86CPUDefinition (x86_def_t) inside the class struct,
   instead keeping a pointer to the existing X86CPUDefinition struct.
 * The "host" class is registered on cpu.c, but the CPUID data
   is filled on instance_init instead of class_init (because KVM has to
   be initialized already).
   * kvm_required field introduced to make sure the "host" class can't
     be used without KVM.

Changes v6 -> v7:
 * Rebase

Changes v7 -> v8:
 * Removed CPU listing code (will be sent as a separate patch)
 * Kept x86_cpudef_setup() (will be addressed in a separate patch)
---
 target-i386/cpu-qom.h |  13 ++++
 target-i386/cpu.c     | 197 ++++++++++++++++++++++++++++++++------------------
 2 files changed, 138 insertions(+), 72 deletions(-)

diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h
index 722f11a..60c5c32 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 6659527..bb72e5b 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -484,7 +484,10 @@ 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;
@@ -497,7 +500,7 @@ 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 | \
@@ -547,8 +550,29 @@ 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)
+
+/* 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",
@@ -1093,6 +1117,33 @@ 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
@@ -1134,44 +1185,74 @@ 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;
+
+    cpu_x86_fill_model_id(host_cpudef.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;
 
-    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);
+    /* 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;
+
+    assert(kvm_enabled());
 
-    cpu_x86_fill_model_id(x86_cpu_def->model_id);
+    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", &error_abort);
 }
 
+
+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;
@@ -1582,32 +1663,6 @@ static PropertyInfo qdev_prop_spinlocks = {
     .set   = x86_set_hv_spinlocks,
 };
 
-static int cpu_x86_find_by_name(X86CPU *cpu, X86CPUDefinition *x86_cpu_def,
-                                const char *name)
-{
-    X86CPUDefinition *def;
-    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", &error_abort);
-        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 '_'.
  */
@@ -1817,19 +1872,11 @@ 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);
@@ -1881,7 +1928,6 @@ 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);
@@ -1892,12 +1938,19 @@ 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");
@@ -1907,14 +1960,6 @@ 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;
@@ -1923,8 +1968,10 @@ 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;
@@ -2615,6 +2662,7 @@ 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;
 
@@ -2666,6 +2714,9 @@ static void x86_cpu_initfn(Object *obj)
         cpu_set_debug_excp_handler(breakpoint_handler);
 #endif
     }
+
+    X86CPUDefinition *def = xcc->cpu_def;
+    x86_cpu_load_def(cpu, def, &error_abort);
 }
 
 static int64_t x86_cpu_get_arch_id(CPUState *cs)
@@ -2748,7 +2799,7 @@ 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,
 };
@@ -2756,6 +2807,8 @@ 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)
-- 
1.8.4.2

-- 
Eduardo


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