--- zzzz-none-000/linux-4.9.279/arch/x86/kernel/apic/io_apic.c	2021-08-08 06:38:54.000000000 +0000
+++ puma7-atom-6591-750/linux-4.9.279/arch/x86/kernel/apic/io_apic.c	2023-02-08 11:43:42.000000000 +0000
@@ -3034,3 +3034,53 @@
 	.activate	= mp_irqdomain_activate,
 	.deactivate	= mp_irqdomain_deactivate,
 };
+
+#if IS_ENABLED(CONFIG_AVM_ENHANCED)
+int IO_APIC_enable_nmi(int irq, const cpumask_t *mask)
+{
+	struct mp_chip_data *data;
+	struct irq_pin_list *pin;
+	struct IO_APIC_route_entry entry;
+	unsigned int dest;
+	unsigned long flags;
+	int result;
+
+	result = 0;
+
+	if (cpumask_empty(mask)) {
+		result = -EINVAL;
+		goto err_out;
+	}
+	apic->cpu_mask_to_apicid_and(mask, mask, &dest);
+
+	data = irq_get_chip_data(irq);
+	if (!data) {
+		result = -EINVAL;
+		goto err_out;
+	}
+
+	raw_spin_lock_irqsave(&ioapic_lock, flags);
+
+	/* TODO: somehow save pin config(s) for restore on disable. */
+	for_each_irq_pin(pin, data->irq_2_pin) {
+		entry = __ioapic_read_entry(pin->apic, pin->pin);
+		entry.dest = dest;
+		entry.delivery_mode = APIC_MODE_NMI;
+		entry.dest_mode = 1; /* logical, i.e. target mask */
+		__ioapic_write_entry(pin->apic, pin->pin, entry);
+	}
+
+	raw_spin_unlock_irqrestore(&ioapic_lock, flags);
+
+err_out:
+	return result;
+}
+EXPORT_SYMBOL(IO_APIC_enable_nmi);
+
+int IO_APIC_disable_nmi(int irq)
+{
+	/* TODO: either restore to default or do an explicit save/restore. */
+	return 0;
+}
+EXPORT_SYMBOL(IO_APIC_disable_nmi);
+#endif /* IS_ENABLED(CONFIG_AVM_ENHANCED) */