@@ -460,6 +460,18 @@ void ich9_pm_device_unplug_request_cb(HotplugHandler *hotplug_dev,
errp);
} else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU) &&
!lpc->pm.cpu_hotplug_legacy) {
+ uint64_t negotiated = lpc->smi_negotiated_features;
+
+ if (negotiated & BIT_ULL(ICH9_LPC_SMI_F_BROADCAST_BIT) &&
+ !(negotiated & BIT_ULL(ICH9_LPC_SMI_F_CPU_HOT_UNPLUG_BIT))) {
+ error_setg(errp, "cpu hot-unplug with SMI wasn't enabled "
+ "by firmware");
+ error_append_hint(errp, "update machine type to a version having "
+ "x-smi-cpu-hotunplug=on and firmware that "
+ "supports CPU hot-unplug with SMM");
+ return;
+ }
+
acpi_cpu_unplug_request_cb(hotplug_dev, &lpc->pm.cpuhp_state,
dev, errp);
} else {