[RFC PATCH-for-9.1 14/21] system: Introduce QMP generic_query_cpu_definitions()

[Philippe Mathieu-Daudé]

Each target use a common template for qmp_query_cpu_definitions().

Extract it as generic_query_cpu_definitions(), keeping the
target-specific implementations as the following SysemuCPUOps
handlers:
 - cpu_list_compare()
 - add_definition()
 - add_alias_definitions()

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 MAINTAINERS                           |  2 +
 include/hw/core/sysemu-cpu-ops.h      | 14 ++++++
 include/qapi/commands-target-compat.h | 14 ++++++
 system/cpu-qmp-cmds.c                 | 71 +++++++++++++++++++++++++++
 system/meson.build                    |  1 +
 5 files changed, 102 insertions(+)
 create mode 100644 include/qapi/commands-target-compat.h
 create mode 100644 system/cpu-qmp-cmds.c

diff --git a/MAINTAINERS b/MAINTAINERS
index af27490243..39d7c14d98 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -148,6 +148,7 @@ M: Richard Henderson <richard.henderson@linaro.org>
 R: Paolo Bonzini <pbonzini@redhat.com>
 S: Maintained
 F: system/cpus.c
+F: system/cpu-qmp-cmds.c
 F: system/cpu-qom-helpers.c
 F: system/watchpoint.c
 F: cpu-common.c
@@ -1894,6 +1895,7 @@ F: qapi/machine-target.json
 F: include/hw/boards.h
 F: include/hw/core/cpu.h
 F: include/hw/cpu/cluster.h
+F: include/qapi/commands-target-compat.h
 F: include/sysemu/numa.h
 F: tests/unit/test-smp-parse.c
 T: git https://gitlab.com/ehabkost/qemu.git machine-next
diff --git a/include/hw/core/sysemu-cpu-ops.h b/include/hw/core/sysemu-cpu-ops.h
index 24d003fe04..2173226e97 100644
--- a/include/hw/core/sysemu-cpu-ops.h
+++ b/include/hw/core/sysemu-cpu-ops.h
@@ -11,6 +11,7 @@
 #define SYSEMU_CPU_OPS_H
 
 #include "hw/core/cpu.h"
+#include "qapi/qapi-types-machine.h"
 
 /*
  * struct SysemuCPUOps: System operations specific to a CPU class
@@ -81,6 +82,19 @@ typedef struct SysemuCPUOps {
      */
     bool (*virtio_is_big_endian)(CPUState *cpu);
 
+    /**
+     * @cpu_list_compare: Sort alphabetically by type name,
+     *                    respecting CPUClass::ordering.
+     */
+    gint (*cpu_list_compare)(gconstpointer cpu_class_a, gconstpointer 
cpu_class_b);
+    /**
+     * @add_definition: Add the @cpu_class definition to @cpu_list.
+     */
+    void (*add_definition)(gpointer cpu_class, gpointer cpu_list);
+    /**
+     * @add_alias_definitions: Add CPU alias definitions to @cpu_list.
+     */
+    void (*add_alias_definitions)(CpuDefinitionInfoList **cpu_list);
     /**
      * @legacy_vmsd: Legacy state for migration.
      *               Do not use in new targets, use #DeviceClass::vmsd instead.
diff --git a/include/qapi/commands-target-compat.h 
b/include/qapi/commands-target-compat.h
new file mode 100644
index 0000000000..86d45d8fcc
--- /dev/null
+++ b/include/qapi/commands-target-compat.h
@@ -0,0 +1,14 @@
+/*
+ * QAPI helpers for target specific QMP commands
+ *
+ * SPDX-FileCopyrightText: 2024 Linaro Ltd.
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#ifndef QAPI_COMPAT_TARGET_H
+#define QAPI_COMPAT_TARGET_H
+
+#include "qapi/qapi-types-machine.h"
+
+CpuDefinitionInfoList *generic_query_cpu_definitions(Error **errp);
+
+#endif
diff --git a/system/cpu-qmp-cmds.c b/system/cpu-qmp-cmds.c
new file mode 100644
index 0000000000..daeb131159
--- /dev/null
+++ b/system/cpu-qmp-cmds.c
@@ -0,0 +1,71 @@
+/*
+ * QAPI helpers for target specific QMP commands
+ *
+ * SPDX-FileCopyrightText: 2024 Linaro Ltd.
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qom/object.h"
+#include "qapi/commands-target-compat.h"
+#include "sysemu/arch_init.h"
+#include "hw/core/cpu.h"
+#include "hw/core/sysemu-cpu-ops.h"
+
+static void cpu_common_add_definition(gpointer data, gpointer user_data)
+{
+    ObjectClass *oc = data;
+    CpuDefinitionInfoList **cpu_list = user_data;
+    CpuDefinitionInfo *info;
+    const char *typename;
+
+    typename = object_class_get_name(oc);
+    info = g_malloc0(sizeof(*info));
+    info->name = cpu_model_from_type(typename);
+    info->q_typename = g_strdup(typename);
+
+    QAPI_LIST_PREPEND(*cpu_list, info);
+}
+
+static void arch_add_cpu_definitions(CpuDefinitionInfoList **cpu_list,
+                                     const char *cpu_typename)
+{
+    ObjectClass *oc;
+    GSList *list;
+    const struct SysemuCPUOps *ops;
+
+    oc = object_class_by_name(cpu_typename);
+    if (!oc) {
+        return;
+    }
+    ops = CPU_CLASS(oc)->sysemu_ops;
+
+    list = object_class_get_list(cpu_typename, false);
+    if (ops->cpu_list_compare) {
+        list = g_slist_sort(list, ops->cpu_list_compare);
+    }
+    g_slist_foreach(list, ops->add_definition ? : cpu_common_add_definition,
+                    cpu_list);
+    g_slist_free(list);
+
+    if (ops->add_alias_definitions) {
+        ops->add_alias_definitions(cpu_list);
+    }
+}
+
+CpuDefinitionInfoList *generic_query_cpu_definitions(Error **errp)
+{
+    CpuDefinitionInfoList *cpu_list = NULL;
+
+    for (unsigned i = 0; i <= QEMU_ARCH_BIT_LAST; i++) {
+        const char *cpu_typename;
+
+        cpu_typename = cpu_typename_by_arch_bit(i);
+        if (!cpu_typename) {
+            continue;
+        }
+        arch_add_cpu_definitions(&cpu_list, cpu_typename);
+    }
+
+    return cpu_list;
+}
diff --git a/system/meson.build b/system/meson.build
index c6ee97e3b2..dd78caa9b7 100644
--- a/system/meson.build
+++ b/system/meson.build
@@ -10,6 +10,7 @@ system_ss.add(files(
   'balloon.c',
   'bootdevice.c',
   'cpus.c',
+  'cpu-qmp-cmds.c',
   'cpu-qom-helpers.c',
   'cpu-throttle.c',
   'cpu-timers.c',
-- 
2.41.0