[RFC v6 10/11] accel: introduce AccelCPUClass extending CPUClass

[Claudio Fontana <cfontana@suse.de>]

add a new optional interface to CPUClass,
which allows accelerators to extend the CPUClass
with additional accelerator-specific initializations.

Signed-off-by: Claudio Fontana <cfontana@suse.de>
---
 MAINTAINERS                 |  1 +
 accel/accel-common.c        | 43 +++++++++++++++++++++++++++++++++++++
 include/hw/core/accel-cpu.h | 28 ++++++++++++++++++++++++
 include/hw/core/cpu.h       |  4 ++++
 4 files changed, 76 insertions(+)
 create mode 100644 include/hw/core/accel-cpu.h

diff --git a/MAINTAINERS b/MAINTAINERS
index df64a0d190..b99526e491 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -435,6 +435,7 @@ R: Paolo Bonzini <pbonzini@redhat.com>
 S: Maintained
 F: include/qemu/accel.h
 F: include/sysemu/accel-ops.h
+F: include/hw/core/accel-cpu.h
 F: accel/accel-*.c
 F: accel/Makefile.objs
 F: accel/stubs/Makefile.objs
diff --git a/accel/accel-common.c b/accel/accel-common.c
index 3910b7dbe0..06afee982e 100644
--- a/accel/accel-common.c
+++ b/accel/accel-common.c
@@ -26,6 +26,9 @@
 #include "qemu/osdep.h"
 #include "qemu/accel.h"
 
+#include "cpu.h"
+#include "hw/core/accel-cpu.h"
+
 #ifndef CONFIG_USER_ONLY
 #include "accel-softmmu.h"
 #endif /* !CONFIG_USER_ONLY */
@@ -46,16 +49,56 @@ AccelClass *accel_find(const char *opt_name)
     return ac;
 }
 
+static void accel_init_cpu_int_aux(ObjectClass *klass, void *opaque)
+{
+    CPUClass *cc = CPU_CLASS(klass);
+    AccelCPUClass *accel_cpu_interface = opaque;
+
+    cc->accel_cpu_interface = accel_cpu_interface;
+    if (accel_cpu_interface->cpu_class_init) {
+        accel_cpu_interface->cpu_class_init(cc);
+    }
+}
+
+/* initialize the arch-specific accel CpuClass interfaces */
+static void accel_init_cpu_interfaces(AccelClass *ac, const char *cpu_type)
+{
+    const char *ac_name; /* AccelClass name */
+    char *acc_name;      /* AccelCPUClass name */
+    ObjectClass *acc;    /* AccelCPUClass */
+
+    ac_name = object_class_get_name(OBJECT_CLASS(ac));
+    g_assert(ac_name != NULL);
+
+    acc_name = g_strdup_printf("%s-%s", ac_name, CPU_RESOLVING_TYPE);
+    acc = object_class_by_name(acc_name);
+    g_free(acc_name);
+
+    if (acc) {
+        object_class_foreach(accel_init_cpu_int_aux, cpu_type, false, acc);
+    }
+}
+
 void accel_init_interfaces(AccelClass *ac, const char *cpu_type)
 {
 #ifndef CONFIG_USER_ONLY
     accel_init_ops_interfaces(ac);
 #endif /* !CONFIG_USER_ONLY */
+
+    accel_init_cpu_interfaces(ac, cpu_type);
 }
 
+static const TypeInfo accel_cpu_type = {
+    .name = TYPE_ACCEL_CPU,
+    .parent = TYPE_OBJECT,
+    .abstract = true,
+    .class_size = sizeof(AccelCPUClass),
+};
+
 static void register_accel_types(void)
 {
     type_register_static(&accel_type);
+    type_register_static(&accel_cpu_type);
 }
 
 type_init(register_accel_types);
diff --git a/include/hw/core/accel-cpu.h b/include/hw/core/accel-cpu.h
new file mode 100644
index 0000000000..380e1c7436
--- /dev/null
+++ b/include/hw/core/accel-cpu.h
@@ -0,0 +1,28 @@
+/*
+ * Accelerator interface, specializes CPUClass
+ *
+ * Copyright 2020 SUSE LLC
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef ACCEL_CPU_H
+#define ACCEL_CPU_H
+
+struct AccelCPUClass {
+    /*< private >*/
+    ObjectClass parent_class;
+    /*< public >*/
+
+    void (*cpu_class_init)(CPUClass *cc);
+    void (*cpu_instance_init)(CPUState *cpu);
+    void (*cpu_realizefn)(CPUState *cpu, Error **errp);
+};
+
+#define TYPE_ACCEL_CPU "accel-" CPU_RESOLVING_TYPE
+#define ACCEL_CPU_NAME(name) (name "-" TYPE_ACCEL_CPU)
+typedef struct AccelCPUClass AccelCPUClass;
+DECLARE_CLASS_CHECKERS(AccelCPUClass, ACCEL_CPU, TYPE_ACCEL_CPU)
+
+#endif /* ACCEL_CPU_H */
diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
index 3d92c967ff..75eb1d8199 100644
--- a/include/hw/core/cpu.h
+++ b/include/hw/core/cpu.h
@@ -76,6 +76,8 @@ typedef struct CPUWatchpoint CPUWatchpoint;
 
 struct TranslationBlock;
 
+struct AccelCPUClass;
+
 /**
  * CPUClass:
  * @class_by_name: Callback to map -cpu command line model name to an
@@ -227,6 +229,8 @@ struct CPUClass {
     /* Keep non-pointer data at the end to minimize holes.  */
     int gdb_num_core_regs;
     bool gdb_stop_before_watchpoint;
+
+    struct AccelCPUClass *accel_cpu_interface;
 };
 
 /*
-- 
2.26.2