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iommu/amd: 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: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
hifive-unleashed-5.1
Alex Williamson 2012-08-04 12:09:03 -06:00 committed by Joerg Roedel
parent a4ff1fc2cc
commit 31fe943599
1 changed files with 22 additions and 3 deletions
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25
drivers/iommu/amd_iommu.c
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@ -296,8 +296,13 @@ static int iommu_init_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,
@ -305,14 +310,28 @@ static int iommu_init_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) {