1 files changed, 31 insertions, 0 deletions

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index d4a4cd445cab..ca3ee46a8d61 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2320,8 +2320,39 @@ static int domain_add_dev_info(struct dmar_domain *domain,
         return 0;
 }
 
+static bool device_has_rmrr(struct pci_dev *dev)
+{
+        struct dmar_rmrr_unit *rmrr;
+        int i;
+
+        for_each_rmrr_units(rmrr) {
+                for (i = 0; i < rmrr->devices_cnt; i++) {
+                        /*
+                         * Return TRUE if this RMRR contains the device that
+                         * is passed in.
+                         */
+                        if (rmrr->devices[i] == dev)
+                                return true;
+                }
+        }
+        return false;
+}
+
 static int iommu_should_identity_map(struct pci_dev *pdev, int startup)
 {
+
+        /*
+         * We want to prevent any device associated with an RMRR from
+         * getting placed into the SI Domain. This is done because
+         * problems exist when devices are moved in and out of domains
+         * and their respective RMRR info is lost. We exempt USB devices
+         * from this process due to their usage of RMRRs that are known
+         * to not be needed after BIOS hand-off to OS.
+         */
+        if (device_has_rmrr(pdev) &&
+            (pdev->class >> 8) != PCI_CLASS_SERIAL_USB)
+                return 0;
+
         if ((iommu_identity_mapping & IDENTMAP_AZALIA) && IS_AZALIA(pdev))
                 return 1;