4.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Joerg Roedel <redacted>

commit 4df4eab168c1c4058603be55a3169d4a45779cc0 upstream.

There is a bug in iommu_context_addr() which will always use
the lower context table, even when the upper context table
needs to be used. Fix this issue.

Fixes: 03ecc32c5274 ("iommu/vt-d: support extended root and context entries")
Reported-by: Xiao, Nan <redacted>
Signed-off-by: Joerg Roedel <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/iommu/intel-iommu.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c

@@ -681,6 +681,7 @@ static inline struct context_entry *iomm
 	struct context_entry *context;
 	u64 *entry;
 
+	entry = &root->lo;
 	if (ecs_enabled(iommu)) {
 		if (devfn >= 0x80) {
 			devfn -= 0x80;

@@ -688,7 +689,6 @@ static inline struct context_entry *iomm
 		}
 		devfn *= 2;
 	}
-	entry = &root->lo;
 	if (*entry & 1)
 		context = phys_to_virt(*entry & VTD_PAGE_MASK);
 	else {