1 files changed, 5 insertions, 5 deletions

diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index d1b3da2960ab..b456b048eca9 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -532,12 +532,13 @@ static bool alloc_p2m(unsigned long pfn)
         unsigned topidx, mididx;
         unsigned long ***top_p, **mid;
         unsigned long *top_mfn_p, *mid_mfn;
+        unsigned long *p2m_orig;
 
         topidx = p2m_top_index(pfn);
         mididx = p2m_mid_index(pfn);
 
         top_p = &p2m_top[topidx];
-        mid = *top_p;
+        mid = ACCESS_ONCE(*top_p);
 
         if (mid == p2m_mid_missing) {
                 /* Mid level is missing, allocate a new one */
@@ -552,7 +553,7 @@ static bool alloc_p2m(unsigned long pfn)
         }
 
         top_mfn_p = &p2m_top_mfn[topidx];
-        mid_mfn = p2m_top_mfn_p[topidx];
+        mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]);
 
         BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
 
@@ -579,11 +580,10 @@ static bool alloc_p2m(unsigned long pfn)
                 }
         }
 
-        if (p2m_top[topidx][mididx] == p2m_identity ||
-            p2m_top[topidx][mididx] == p2m_missing) {
+        p2m_orig = ACCESS_ONCE(p2m_top[topidx][mididx]);
+        if (p2m_orig == p2m_identity || p2m_orig == p2m_missing) {
                 /* p2m leaf page is missing */
                 unsigned long *p2m;
-                unsigned long *p2m_orig = p2m_top[topidx][mididx];
 
                 p2m = alloc_p2m_page();
                 if (!p2m)