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@xxxxxxxxxx>
---
drivers/iommu/amd_iommu.c | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 6d1cbdf..b64502d 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -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) {
--
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