iommu/dma: Don't reserve PCI I/O windows

commit 938f1bbe upstream.

Even if a host controller's CPU-side MMIO windows into PCI I/O space do
happen to leak into PCI memory space such that it might treat them as
peer addresses, trying to reserve the corresponding I/O space addresses
doesn't do anything to help solve that problem. Stop doing a silly thing.

Fixes: fade1ec0 ("iommu/dma: Avoid PCI host bridge windows")
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/iommu/dma-iommu.c

@@ -175,8 +175,7 @@ static void iova_reserve_pci_windows(struct pci_dev *dev,
 	unsigned long lo, hi;
 
 	resource_list_for_each_entry(window, &bridge->windows) {
-		if (resource_type(window->res) != IORESOURCE_MEM &&
-		    resource_type(window->res) != IORESOURCE_IO)
+		if (resource_type(window->res) != IORESOURCE_MEM)
 			continue;
 
 		lo = iova_pfn(iovad, window->res->start - window->offset);