iommu/hyper-v: Implement select() method on remapping irqdomain

Preparatory for removing irq_remapping_get_irq_domain()

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-27-dwmw2@infradead.org

drivers/iommu/hyperv-iommu.c

@@ -101,7 +101,16 @@ static void hyperv_irq_remapping_free(struct irq_domain *domain,
 	irq_domain_free_irqs_common(domain, virq, nr_irqs);
 }
 
+static int hyperv_irq_remapping_select(struct irq_domain *d,
+				       struct irq_fwspec *fwspec,
+				       enum irq_domain_bus_token bus_token)
+{
+	/* Claim only the first (and only) I/OAPIC */
+	return x86_fwspec_is_ioapic(fwspec) && fwspec->param[0] == 0;
+}
+
 static const struct irq_domain_ops hyperv_ir_domain_ops = {
+	.select = hyperv_irq_remapping_select,
 	.alloc = hyperv_irq_remapping_alloc,
 	.free = hyperv_irq_remapping_free,
 };