PCI/MSI: Fix MSI IRQ domains for VFs on virtual buses

static void pci_set_bus_msi_domain(struct pci_bus *bus)

{

	struct irq_domain *d;

	struct pci_bus *b;

	/*

	 * Either bus is the root, and we must obtain it from the

	 * firmware, or we inherit it from the bridge device.

	 * The bus can be a root bus, a subordinate bus, or a virtual bus

	 * created by an SR-IOV device.  Walk up to the first bridge device

	 * found or derive the domain from the host bridge.

	 */

	if (pci_is_root_bus(bus))

		d = pci_host_bridge_msi_domain(bus);

	else

		d = dev_get_msi_domain(&bus->self->dev);

	for (b = bus, d = NULL; !d && !pci_is_root_bus(b); b = b->parent) {

		if (b->self)

			d = dev_get_msi_domain(&b->self->dev);

	}

	if (!d)

		d = pci_host_bridge_msi_domain(b);

	dev_set_msi_domain(&bus->dev, d);

}