From b4f05942926b6cf1b064babcd0fe8fcc32630ecc Mon Sep 17 00:00:00 2001
From: Lu Baolu <baolu.lu@linux.intel.com>
Date: Tue, 19 Mar 2019 23:23:25 +0800
Subject: [PATCH] iommu/vt-d: Fix NULL pointer reference in intel_svm_bind_mm()

mainline inclusion
from mainline-5.1-rc1
commit c56cba5daf45d2d091ef1cfe2f1d6a930446687b
category: bugfix
bugzilla: NA
CVE: NA

-------------------------------------------------
Intel IOMMU could be turned off with intel_iommu=off. If Intel
IOMMU is off,  the intel_iommu struct will not be initialized.
When device drivers call intel_svm_bind_mm(), the NULL pointer
reference will happen there.

Add dmar_disabled check to avoid NULL pointer reference.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reported-by: Dave Jiang <dave.jiang@intel.com>
Fixes: 2f26e0a9c9860 ("iommu/vt-d: Add basic SVM PASID support")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
(cherry picked from commit c56cba5daf45d2d091ef1cfe2f1d6a930446687b)
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 drivers/iommu/intel-svm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 188f4eaed6e5..fd8730b2cd46 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -293,7 +293,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
 	int pasid_max;
 	int ret;
 
-	if (!iommu)
+	if (!iommu || dmar_disabled)
 		return -EINVAL;
 
 	if (dev_is_pci(dev)) {
-- 
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