cpu: call plugin init hook asynchronously

This ensures we run during a cpu_exec, which allows to call start/end
exclusive from this init hook (needed for new scoreboard API introduced
later).

async work is run before any tb is translated/executed, so we can
guarantee plugin init will be called before any other hook.

The previous change made sure that any idle/resume cb call will not be
done before initializing plugin for a given vcpu.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-Id: <20240213094009.150349-5-pierrick.bouvier@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240227144335.1196131-20-alex.bennee@linaro.org>

hw/core/cpu-common.c

@@ -194,6 +194,11 @@ static void cpu_common_parse_features(const char *typename, char *features,
     }
 }
 
+static void qemu_plugin_vcpu_init__async(CPUState *cpu, run_on_cpu_data unused)
+{
+    qemu_plugin_vcpu_init_hook(cpu);
+}
+
 static void cpu_common_realizefn(DeviceState *dev, Error **errp)
 {
     CPUState *cpu = CPU(dev);
@@ -217,9 +222,9 @@ static void cpu_common_realizefn(DeviceState *dev, Error **errp)
         cpu_resume(cpu);
     }
 
-    /* Plugin initialization must wait until the cpu is fully realized. */
+    /* Plugin initialization must wait until the cpu start executing code */
     if (tcg_enabled()) {
-        qemu_plugin_vcpu_init_hook(cpu);
+        async_run_on_cpu(cpu, qemu_plugin_vcpu_init__async, RUN_ON_CPU_NULL);
     }
 
     /* NOTE: latest generic point where the cpu is fully realized */