+#ifdef CONFIG_KVM_BOOK3S_64_HV
+/* For now use fixed-size 16MB page table */
+#define HPT_ORDER 24
+#define HPT_NPTEG (1ul << (HPT_ORDER - 7)) /* 128B per pteg */
+#define HPT_NPTE (HPT_NPTEG << 3) /* 8 PTEs per PTEG */
+#define HPT_HASH_MASK (HPT_NPTEG - 1)
+#endif
+
+/*
+ * We use a lock bit in HPTE dword 0 to synchronize updates and
+ * accesses to each HPTE, and another bit to indicate non-present
+ * HPTEs.
+ */
+#define HPTE_V_HVLOCK 0x40UL
+
+static inline long try_lock_hpte(unsigned long *hpte, unsigned long bits)
+{
+ unsigned long tmp, old;
+
+ asm volatile(" ldarx %0,0,%2\n"
+ " and. %1,%0,%3\n"
+ " bne 2f\n"
+ " ori %0,%0,%4\n"
+ " stdcx. %0,0,%2\n"
+ " beq+ 2f\n"
+ " li %1,%3\n"
+ "2: isync"
+ : "=&r" (tmp), "=&r" (old)
+ : "r" (hpte), "r" (bits), "i" (HPTE_V_HVLOCK)
+ : "cc", "memory");
+ return old == 0;
+}
+