diff --git a/hypervisor/debug/sbuf.c b/hypervisor/debug/sbuf.c
index 72527d345..e03fb9a0d 100644
--- a/hypervisor/debug/sbuf.c
+++ b/hypervisor/debug/sbuf.c
@@ -29,10 +29,11 @@ uint32_t sbuf_get(struct shared_buf *sbuf, uint8_t *data)
 {
 	const void *from;
 	uint32_t ele_size;
+	uint64_t rflags;
 
-	stac();
+	stac_save(&rflags);
 	if (sbuf_is_empty(sbuf)) {
-		clac();
+		ac_restore(&rflags);
 		/* no data available */
 		return 0;
 	}
@@ -44,7 +45,7 @@ uint32_t sbuf_get(struct shared_buf *sbuf, uint8_t *data)
 	sbuf->head = sbuf_next_ptr(sbuf->head, sbuf->ele_size, sbuf->size);
 
 	ele_size = sbuf->ele_size;
-	clac();
+	ac_restore(&rflags);
 
 	return ele_size;
 }
@@ -72,9 +73,10 @@ uint32_t sbuf_put(struct shared_buf *sbuf, uint8_t *data)
 	void *to;
 	uint32_t next_tail;
 	uint32_t ele_size;
+	uint64_t rflags;
 	bool trigger_overwrite = false;
 
-	stac();
+	stac_save(&rflags);
 	next_tail = sbuf_next_ptr(sbuf->tail, sbuf->ele_size, sbuf->size);
 	/* if this write would trigger overrun */
 	if (next_tail == sbuf->head) {
@@ -82,7 +84,7 @@ uint32_t sbuf_put(struct shared_buf *sbuf, uint8_t *data)
 		sbuf->overrun_cnt += sbuf->flags & OVERRUN_CNT_EN;
 		if ((sbuf->flags & OVERWRITE_EN) == 0U) {
 			/* if not enable over write, return here. */
-			clac();
+			ac_restore(&rflags);
 			return 0;
 		}
 		trigger_overwrite = true;
@@ -99,7 +101,7 @@ uint32_t sbuf_put(struct shared_buf *sbuf, uint8_t *data)
 	sbuf->tail = next_tail;
 
 	ele_size = sbuf->ele_size;
-	clac();
+	ac_restore(&rflags);
 
 	return ele_size;
 }
diff --git a/hypervisor/include/arch/x86/cpu.h b/hypervisor/include/arch/x86/cpu.h
index e22818374..0e3cc310b 100644
--- a/hypervisor/include/arch/x86/cpu.h
+++ b/hypervisor/include/arch/x86/cpu.h
@@ -83,6 +83,9 @@
 #define CR4_SMAP                (1UL<<21U)
 #define CR4_PKE                 (1UL<<22U)	/* Protect-key-enable */
 
+#define RFLAGS_C (1U<<0U)
+#define RFLAGS_Z (1U<<6U)
+#define RFLAGS_AC (1U<<18U)
 
 /*
  * Entries in the Interrupt Descriptor Table (IDT)
@@ -542,6 +545,23 @@ static inline void clac(void)
 	asm volatile ("clac" : : : "memory");
 }
 
+/* Save rflags register and set AC bit */
+static inline void stac_save(uint64_t *p_rflags)
+{
+	CPU_RFLAGS_SAVE(p_rflags);
+	asm volatile ("stac" : : : "memory");
+}
+
+/* Restore AC bit saved in p_rflags */
+static inline void ac_restore(uint64_t *p_rflags)
+{
+	if (*p_rflags & RFLAGS_AC) {
+		stac();
+	} else {
+		clac();
+	}
+}
+
 #else /* ASSEMBLER defined */
 
 #endif /* ASSEMBLER defined */