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Commit a4ff1fc2 authored by Alex Williamson's avatar Alex Williamson Committed by Joerg Roedel
Browse files

iommu/intel: Fix ACS path checking 



SR-IOV can create buses without a bridge.  There may be other cases
where this happens as well.  In these cases skip to the parent bus
and continue testing devices there.

Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Tested-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
parent 1adb7d31

drivers/iommu/intel-iommu.c

+22 −3
Original line number Diff line number Diff line
@@ -4125,8 +4125,13 @@ static int intel_iommu_add_device(struct device *dev) 
	} else

		dma_pdev = pci_dev_get(pdev);



	/* Account for quirked devices */

	swap_pci_ref(&dma_pdev, pci_get_dma_source(dma_pdev));



	/*

	 * If it's a multifunction device that does not support our

	 * required ACS flags, add to the same group as function 0.

	 */

	if (dma_pdev->multifunction &&

	    !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS))

		swap_pci_ref(&dma_pdev,
@@ -4134,14 +4139,28 @@ static int intel_iommu_add_device(struct device *dev) 
					  PCI_DEVFN(PCI_SLOT(dma_pdev->devfn),

					  0)));



	/*

	 * Devices on the root bus go through the iommu.  If that's not us,

	 * find the next upstream device and test ACS up to the root bus.

	 * Finding the next device may require skipping virtual buses.

	 */

	while (!pci_is_root_bus(dma_pdev->bus)) {

		if (pci_acs_path_enabled(dma_pdev->bus->self,

					 NULL, REQ_ACS_FLAGS))

		struct pci_bus *bus = dma_pdev->bus;



		while (!bus->self) {

			if (!pci_is_root_bus(bus))

				bus = bus->parent;

			else

				goto root_bus;

		}



		if (pci_acs_path_enabled(bus->self, NULL, REQ_ACS_FLAGS))

			break;



		swap_pci_ref(&dma_pdev, pci_dev_get(dma_pdev->bus->self));

		swap_pci_ref(&dma_pdev, pci_dev_get(bus->self));

	}



root_bus:

	group = iommu_group_get(&dma_pdev->dev);

	pci_dev_put(dma_pdev);

	if (!group) {