Merge git://git.infradead.org/intel-iommu

Pull Intel IOMMU fix from David Woodhouse:
 "This fixes an oops when attempting to enable 1:1 passthrough mode for
  devices on which VT-d translation was disabled anyway.

  It's actually a long-standing bug but recent changes (commit
  18436afdc11a: "iommu/vt-d: Allow RMRR on graphics devices too") have
  made it much easier to trigger with 'iommu=pt intel_iommu=igfx_off' on
  the command line"

* git://git.infradead.org/intel-iommu:
  iommu/vt-d: Fix passthrough mode with translation-disabled devices

1 files changed, 8 insertions, 5 deletions

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 68d43beccb7e..2ffe58969944 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -696,6 +696,11 @@ static inline struct context_entry *iommu_context_addr(struct intel_iommu *iommu
         return &context[devfn];
 }
 
+static int iommu_dummy(struct device *dev)
+{
+        return dev->archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO;
+}
+
 static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devfn)
 {
         struct dmar_drhd_unit *drhd = NULL;
@@ -705,6 +710,9 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf
         u16 segment = 0;
         int i;
 
+        if (iommu_dummy(dev))
+                return NULL;
+
         if (dev_is_pci(dev)) {
                 pdev = to_pci_dev(dev);
                 segment = pci_domain_nr(pdev->bus);
@@ -2969,11 +2977,6 @@ static inline struct dmar_domain *get_valid_domain_for_dev(struct device *dev)
         return __get_valid_domain_for_dev(dev);
 }
 
-static int iommu_dummy(struct device *dev)
-{
-        return dev->archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO;
-}
-
 /* Check if the dev needs to go through non-identity map and unmap process.*/
 static int iommu_no_mapping(struct device *dev)
 {