diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 738fd0f2..eb1bf00 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -481,12 +481,16 @@
 	return 1;
 }
 #else
+/* This check is needed to avoid cache aliasing when PAT is enabled */
 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 {
 	u64 from = ((u64)pfn) << PAGE_SHIFT;
 	u64 to = from + size;
 	u64 cursor = from;
 
+	if (!pat_enabled)
+		return 1;
+
 	while (cursor < to) {
 		if (!devmem_is_allowed(pfn)) {
 			printk(KERN_INFO