diff --git a/hypervisor/arch/x86/vtd.c b/hypervisor/arch/x86/vtd.c
index 67de8eae6..c687eabd7 100644
--- a/hypervisor/arch/x86/vtd.c
+++ b/hypervisor/arch/x86/vtd.c
@@ -1290,6 +1290,33 @@ static bool is_irte_reserved(const struct dmar_drhd_rt *dmar_unit, uint16_t inde
 	return ((dmar_unit->irte_reserved_bitmap[index >> 6U] & (1UL << (index & 0x3FU))) != 0UL);
 }
 
+int32_t dmar_reserve_irte(const struct intr_source *intr_src, uint16_t num, uint16_t *start_id)
+{
+	struct dmar_drhd_rt *dmar_unit;
+	union pci_bdf sid;
+	uint64_t mask = (1UL << num) - 1U;
+	int32_t ret = -EINVAL;
+
+	if (intr_src->is_msi) {
+		dmar_unit = device_to_dmaru((uint8_t)intr_src->src.msi.bits.b, intr_src->src.msi.fields.devfun);
+		sid.value = (uint16_t)(intr_src->src.msi.value);
+	} else {
+		dmar_unit = ioapic_to_dmaru(intr_src->src.ioapic_id, &sid);
+	}
+
+	if (is_dmar_unit_valid(dmar_unit, sid)) {
+		*start_id = alloc_irtes(dmar_unit, num);
+		if (*start_id < CONFIG_MAX_IR_ENTRIES) {
+			dmar_unit->irte_reserved_bitmap[*start_id >> 6U] |= mask << (*start_id & 0x3FU);
+		}
+		ret = 0;
+	}
+
+	pr_dbg("%s: for dev 0x%x:%x.%x, reserve %u entry for MSI(%d), start from %d",
+		__func__, sid.bits.b, sid.bits.d, sid.bits.f, num, intr_src->is_msi, *start_id);
+	return ret;
+}
+
 int32_t dmar_assign_irte(const struct intr_source *intr_src, union dmar_ir_entry *irte,
 	uint16_t idx_in, uint16_t *idx_out)
 {
diff --git a/hypervisor/include/arch/x86/vtd.h b/hypervisor/include/arch/x86/vtd.h
index bfd550dd2..90f103393 100644
--- a/hypervisor/include/arch/x86/vtd.h
+++ b/hypervisor/include/arch/x86/vtd.h
@@ -671,6 +671,21 @@ void resume_iommu(void);
  */
 int32_t init_iommu(void);
 
+/**
+ * @brief Reserve num continuous IRTEs.
+ *
+ * @param[in] intr_src filled with type of interrupt source and the source
+ * @param[in] num number of IRTEs to reserve
+ * @param[out] start_id stard index of reserved IRTEs, caller should check the value is INVALID_IRTE_ID or not.
+ *
+ * @retval 0 on success, caller should check whether the returned start index is valid or not.
+ * @retval -EINVAL if corresponding DMAR is not preset.
+ *
+ * @pre num can only be 2, 4, 8, 16 or 32
+ *
+ */
+int32_t dmar_reserve_irte(const struct intr_source *intr_src, uint16_t num, uint16_t *start_id);
+
 /**
  * @brief Assign RTE for Interrupt Remapping Table.
  *