extern int alloc_iommu(struct dmar_drhd_unit *drhd);
extern void free_iommu(struct intel_iommu *iommu);
extern int dmar_enable_qi(struct intel_iommu *iommu);
+extern void dmar_disable_qi(struct intel_iommu *iommu);
extern void qi_global_iec(struct intel_iommu *iommu);
extern int qi_flush_context(struct intel_iommu *iommu, u16 did, u16 sid,