diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index d15f0bc8a7..6b8ff46aaa 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -1492,7 +1492,7 @@ static int gicv3_iomem_deny_access(struct domain *d)
     if ( vbase != INVALID_PADDR )
     {
         mfn = vbase >> PAGE_SHIFT;
-        nr = PFN_UP(csize);
+        nr = PFN_UP(vsize);
         return iomem_deny_access(d, mfn, mfn + nr - 1);
     }