+{
+	struct task_struct *tsk = __this_cpu_read(vmbus_irqd);
+
+	__this_cpu_write(vmbus_irq_pending, true);
+	wake_up_process(tsk);
+}
+
+static void vmbus_irqd_setup(unsigned int cpu)
+{
+	sched_set_fifo(current);
+}
+
+static int vmbus_irqd_should_run(unsigned int cpu)
+{
+	return __this_cpu_read(vmbus_irq_pending);
+}
+
+static void run_vmbus_irqd(unsigned int cpu)
+{
+	__this_cpu_write(vmbus_irq_pending, false);
+	__vmbus_isr();
+}
+
+static bool vmbus_irq_initialized;
+
+static struct smp_hotplug_thread vmbus_irq_threads = {
+	.store                  = &vmbus_irqd,
+	.setup			= vmbus_irqd_setup,
+	.thread_should_run      = vmbus_irqd_should_run,
+	.thread_fn              = run_vmbus_irqd,
+	.thread_comm            = "vmbus_irq/%u",
+};
+
+void vmbus_isr(void)
+{
+	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+		vmbus_irqd_wake();
+	} else {
+		lockdep_hardirq_threaded();
+		__vmbus_isr();
+	}
+}
 EXPORT_SYMBOL_FOR_MODULES(vmbus_isr, "mshv_vtl");
 
 static irqreturn_t vmbus_percpu_isr(int irq, void *dev_id)
@@ -1462,6 +1510,13 @@ static int vmbus_bus_init(void)
 	 * the VMbus interrupt handler.
 	 */
 
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && !vmbus_irq_initialized) {
+		ret = smpboot_register_percpu_thread(&vmbus_irq_threads);
+		if (ret)
+			goto err_kthread;
+		vmbus_irq_initialized = true;
+	}
+
 	if (vmbus_irq == -1) {
 		hv_setup_vmbus_handler(vmbus_isr);
 	} else {
@@ -1507,6 +1562,11 @@ err_connect:
 		free_percpu(vmbus_evt);
 	}
 err_setup:
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && vmbus_irq_initialized) {
+		smpboot_unregister_percpu_thread(&vmbus_irq_threads);
+		vmbus_irq_initialized = false;
+	}
+err_kthread:
 	bus_unregister(&hv_bus);
 	return ret;
 }
@@ -2976,6 +3036,10 @@ static void __exit vmbus_exit(void)
 		free_percpu_irq(vmbus_irq, vmbus_evt);
 		free_percpu(vmbus_evt);
 	}
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && vmbus_irq_initialized) {
+		smpboot_unregister_percpu_thread(&vmbus_irq_threads);
+		vmbus_irq_initialized = false;
+	}
 	for_each_online_cpu(cpu) {
 		struct hv_per_cpu_context *hv_cpu
 			= per_cpu_ptr(hv_context.cpu_context, cpu);[PATCH 6.19 780/781] Drivers: hv: vmbus: Use kthread for vmbus interrupts on PREEMPT_RTGreg Kroah-Hartman <gregkh@linuxfoundation.org> undefinedstable@vger.kernel.org undefined undefined undefined undefined undefined undefined´l†•w