From 0053716c302592cc5ee9b5f3786b7b1aea5631ca Mon Sep 17 00:00:00 2001
From: Lu Baolu <baolu.lu@linux.intel.com>
Date: Fri, 3 Nov 2017 10:51:34 -0600
Subject: [PATCH] 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>
---
 drivers/iommu/intel-svm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 43280ca282df4..ed1cf7c5a43ba 100644
--- 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)
-- 
2.39.5