accel/system: Introduce @x-accel-stats QMP command

Unstable QMP 'x-accel-stats' dispatches to the
AccelOpsClass::get_stats() and get_vcpu_stats() handlers.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Message-Id: <20250715140048.84942-4-philmd@linaro.org>

accel/accel-qmp.c

@@ -0,0 +1,35 @@
+/*
+ * QMP commands related to accelerators
+ *
+ * Copyright (c) Linaro
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/accel.h"
+#include "qapi/type-helpers.h"
+#include "qapi/qapi-commands-accelerator.h"
+#include "accel/accel-ops.h"
+#include "accel/accel-cpu-ops.h"
+#include "hw/core/cpu.h"
+
+HumanReadableText *qmp_x_accel_stats(Error **errp)
+{
+    AccelState *accel = current_accel();
+    AccelClass *acc = ACCEL_GET_CLASS(accel);
+    g_autoptr(GString) buf = g_string_new("");
+
+    if (acc->get_stats) {
+        acc->get_stats(accel, buf);
+    }
+    if (acc->ops->get_vcpu_stats) {
+        CPUState *cpu;
+
+        CPU_FOREACH(cpu) {
+            acc->ops->get_vcpu_stats(cpu, buf);
+        }
+    }
+
+    return human_readable_text_from_str(buf);
+}

accel/accel-system.c

@@ -26,6 +26,7 @@
 #include "qemu/osdep.h"
 #include "qemu/accel.h"
 #include "hw/boards.h"
+#include "hw/core/cpu.h"
 #include "accel/accel-ops.h"
 #include "accel/accel-cpu-ops.h"
 #include "system/cpus.h"

accel/meson.build

@@ -1,6 +1,6 @@
 common_ss.add(files('accel-common.c'))
 specific_ss.add(files('accel-target.c'))
-system_ss.add(files('accel-system.c', 'accel-blocker.c'))
+system_ss.add(files('accel-system.c', 'accel-blocker.c', 'accel-qmp.c'))
 user_ss.add(files('accel-user.c'))
 
 subdir('tcg')

include/accel/accel-cpu-ops.h

@@ -65,6 +65,9 @@ struct AccelOpsClass {
     /* handle_interrupt is mandatory. */
     void (*handle_interrupt)(CPUState *cpu, int mask);
 
+    /* get_vcpu_stats: Append statistics of this @cpu to @buf */
+    void (*get_vcpu_stats)(CPUState *cpu, GString *buf);
+
     /**
      * @get_virtual_clock: fetch virtual clock
      * @set_virtual_clock: set virtual clock

include/accel/accel-ops.h

@@ -25,6 +25,8 @@ struct AccelClass {
     int (*init_machine)(AccelState *as, MachineState *ms);
     bool (*cpu_common_realize)(CPUState *cpu, Error **errp);
     void (*cpu_common_unrealize)(CPUState *cpu);
+    /* get_stats: Append statistics to @buf */
+    void (*get_stats)(AccelState *as, GString *buf);
 
     /* system related hooks */
     void (*setup_post)(AccelState *as);

qapi/accelerator.json

@@ -37,3 +37,20 @@
 #     <- { "return": { "enabled": true, "present": true } }
 ##
 { 'command': 'query-kvm', 'returns': 'KvmInfo' }
+
+##
+# @x-accel-stats:
+#
+# Query accelerator statistics
+#
+# Features:
+#
+# @unstable: This command is meant for debugging.
+#
+# Returns: accelerator statistics
+#
+# Since: 10.1
+##
+{ 'command': 'x-accel-stats',
+  'returns': 'HumanReadableText',
+  'features': [ 'unstable' ] }