1 files changed, 7 insertions, 0 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 7233bd7e357b..9c4294986af7 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -482,6 +482,13 @@ static int split_large_page(pte_t *kpte, unsigned long address)
         pbase = (pte_t *)page_address(base);
         paravirt_alloc_pte(&init_mm, page_to_pfn(base));
         ref_prot = pte_pgprot(pte_clrhuge(*kpte));
+        /*
+         * If we ever want to utilize the PAT bit, we need to
+         * update this function to make sure it's converted from
+         * bit 12 to bit 7 when we cross from the 2MB level to
+         * the 4K level:
+         */
+        WARN_ON_ONCE(pgprot_val(ref_prot) & _PAGE_PAT_LARGE);
 
 #ifdef CONFIG_X86_64
         if (level == PG_LEVEL_1G) {