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Commit aadad097 authored by Srinath Mannam's avatar Srinath Mannam Committed by Bjorn Helgaas
Browse files

iommu/dma: Reserve IOVA for PCIe inaccessible DMA address 



The dma_ranges list field of PCI host bridge structure has resource entries
in sorted order representing address ranges allowed for DMA transfers.

Process the list and reserve IOVA addresses that are not present in its
resource entries (ie DMA memory holes) to prevent allocating IOVA addresses
that cannot be accessed by PCI devices.

Based-on-a-patch-by: default avatarOza Pawandeep <oza.oza@broadcom.com>
Signed-off-by: default avatarSrinath Mannam <srinath.mannam@broadcom.com>
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarOza Pawandeep <poza@codeaurora.org>
Acked-by: default avatarRobin Murphy <robin.murphy@arm.com>
parent e80a91ad

drivers/iommu/dma-iommu.c

+32 −3
Original line number Diff line number Diff line
@@ -206,12 +206,13 @@ static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie, 
	return 0;

}



static void iova_reserve_pci_windows(struct pci_dev *dev,

static int iova_reserve_pci_windows(struct pci_dev *dev,

		struct iova_domain *iovad)

{

	struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus);

	struct resource_entry *window;

	unsigned long lo, hi;

	phys_addr_t start = 0, end;



	resource_list_for_each_entry(window, &bridge->windows) {

		if (resource_type(window->res) != IORESOURCE_MEM)
@@ -221,6 +222,31 @@ static void iova_reserve_pci_windows(struct pci_dev *dev, 
		hi = iova_pfn(iovad, window->res->end - window->offset);

		reserve_iova(iovad, lo, hi);

	}



	/* Get reserved DMA windows from host bridge */

	resource_list_for_each_entry(window, &bridge->dma_ranges) {

		end = window->res->start - window->offset;

resv_iova:

		if (end > start) {

			lo = iova_pfn(iovad, start);

			hi = iova_pfn(iovad, end);

			reserve_iova(iovad, lo, hi);

		} else {

			/* dma_ranges list should be sorted */

			dev_err(&dev->dev, "Failed to reserve IOVA\n");

			return -EINVAL;

		}



		start = window->res->end - window->offset + 1;

		/* If window is last entry */

		if (window->node.next == &bridge->dma_ranges &&

		    end != ~(dma_addr_t)0) {

			end = ~(dma_addr_t)0;

			goto resv_iova;

		}

	}



	return 0;

}



static int iova_reserve_iommu_regions(struct device *dev,
@@ -232,8 +258,11 @@ static int iova_reserve_iommu_regions(struct device *dev, 
	LIST_HEAD(resv_regions);

	int ret = 0;



	if (dev_is_pci(dev))

		iova_reserve_pci_windows(to_pci_dev(dev), iovad);

	if (dev_is_pci(dev)) {

		ret = iova_reserve_pci_windows(to_pci_dev(dev), iovad);

		if (ret)

			return ret;

	}



	iommu_get_resv_regions(dev, &resv_regions);

	list_for_each_entry(region, &resv_regions, list) {