iommu/vt-d: Clear pasid table entry when memory unbound

In intel_svm_unbind_mm(), pasid table entry must be cleared during
svm free. Otherwise, hardware may be set up with a wild pointer.

Suggested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 43280ca282df475464b81cb6a559bcbe369cfc6f..ed1cf7c5a43ba33cc04ff32d1c88efcbb49bdbde 100644 (file)
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -458,6 +458,8 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
                                kfree_rcu(sdev, rcu);
 
                                if (list_empty(&svm->devs)) {
+                                       svm->iommu->pasid_table[svm->pasid].val = 0;
+                                       wmb();
 
                                        idr_remove(&svm->iommu->pasid_idr, svm->pasid);
                                        if (svm->mm)