From 7e58326ad7e79b8c5dbcc6f24e9dc1523d84c11b Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Tue, 7 Feb 2017 16:28:11 +0800
Subject: [PATCH] intel_iommu: vtd_slpt_level_shift check level

This helps in debugging incorrect level passed in.

Reviewed-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/i386/intel_iommu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index ad304f681c..22d8226e43 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -168,6 +168,7 @@ static gboolean vtd_hash_remove_by_domain(gpointer key, gpointer value,
 /* The shift of an addr for a certain level of paging structure */
 static inline uint32_t vtd_slpt_level_shift(uint32_t level)
 {
+    assert(level != 0);
     return VTD_PAGE_SHIFT_4K + (level - 1) * VTD_SL_LEVEL_BITS;
 }