diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
index 6127c5e3a19ba29ad95b4a7703780f35f5365d71..1202d5ca2fb582d1a71cad1c85f65b61b907c441 100644
--- a/arch/x86/mm/mpx.c
+++ b/arch/x86/mm/mpx.c
@@ -723,11 +723,23 @@ static unsigned long mpx_get_bt_entry_offset_bytes(struct mm_struct *mm,
  */
 static inline unsigned long bd_entry_virt_space(struct mm_struct *mm)
 {
-	unsigned long long virt_space = (1ULL << boot_cpu_data.x86_virt_bits);
-	if (is_64bit_mm(mm))
-		return virt_space / MPX_BD_NR_ENTRIES_64;
-	else
-		return virt_space / MPX_BD_NR_ENTRIES_32;
+	unsigned long long virt_space;
+	unsigned long long GB = (1ULL << 30);
+
+	/*
+	 * This covers 32-bit emulation as well as 32-bit kernels
+	 * running on 64-bit harware.
+	 */
+	if (!is_64bit_mm(mm))
+		return (4ULL * GB) / MPX_BD_NR_ENTRIES_32;
+
+	/*
+	 * 'x86_virt_bits' returns what the hardware is capable
+	 * of, and returns the full >32-bit adddress space when
+	 * running 32-bit kernels on 64-bit hardware.
+	 */
+	virt_space = (1ULL << boot_cpu_data.x86_virt_bits);
+	return virt_space / MPX_BD_NR_ENTRIES_64;
 }
 
 /*