2 files changed, 38 insertions, 12 deletions

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 21d02b0d907c..5a02d0776a66 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -287,14 +287,27 @@ static struct pci_dev *get_isolation_root(struct pci_dev *pdev)
 
         /*
          * If it's a multifunction device that does not support our
-         * required ACS flags, add to the same group as function 0.
+         * required ACS flags, add to the same group as lowest numbered
+         * function that also does not suport the required ACS flags.
          */
         if (dma_pdev->multifunction &&
-            !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS))
-                swap_pci_ref(&dma_pdev,
-                             pci_get_slot(dma_pdev->bus,
-                                          PCI_DEVFN(PCI_SLOT(dma_pdev->devfn),
-                                          0)));
+            !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)) {
+                u8 i, slot = PCI_SLOT(dma_pdev->devfn);
+
+                for (i = 0; i < 8; i++) {
+                        struct pci_dev *tmp;
+
+                        tmp = pci_get_slot(dma_pdev->bus, PCI_DEVFN(slot, i));
+                        if (!tmp)
+                                continue;
+
+                        if (!pci_acs_enabled(tmp, REQ_ACS_FLAGS)) {
+                                swap_pci_ref(&dma_pdev, tmp);
+                                break;
+                        }
+                        pci_dev_put(tmp);
+                }
+        }
 
         /*
          * Devices on the root bus go through the iommu.  If that's not us,
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index b4f0e28dfa41..eec0d3e04bf5 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4182,14 +4182,27 @@ static int intel_iommu_add_device(struct device *dev)
 
         /*
          * If it's a multifunction device that does not support our
-         * required ACS flags, add to the same group as function 0.
+         * required ACS flags, add to the same group as lowest numbered
+         * function that also does not suport the required ACS flags.
          */
         if (dma_pdev->multifunction &&
-            !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS))
-                swap_pci_ref(&dma_pdev,
-                             pci_get_slot(dma_pdev->bus,
-                                          PCI_DEVFN(PCI_SLOT(dma_pdev->devfn),
-                                          0)));
+            !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)) {
+                u8 i, slot = PCI_SLOT(dma_pdev->devfn);
+
+                for (i = 0; i < 8; i++) {
+                        struct pci_dev *tmp;
+
+                        tmp = pci_get_slot(dma_pdev->bus, PCI_DEVFN(slot, i));
+                        if (!tmp)
+                                continue;
+
+                        if (!pci_acs_enabled(tmp, REQ_ACS_FLAGS)) {
+                                swap_pci_ref(&dma_pdev, tmp);
+                                break;
+                        }
+                        pci_dev_put(tmp);
+                }
+        }
 
         /*
          * Devices on the root bus go through the iommu.  If that's not us,