Hello all, It seems to me that when dom0 uses in/out instructions, GP fault will occur, And Xen will check the io accessing permissions, and then performs the operation for dom0. My question is : why not use the io-bitmap which is in TSS, to allow dom0 to access the physical devices'' IO ports? As to the mmio, the MMU virtualization can also allow dom0 to map device memory areas to its virtual memory space, so that there will be no VMM intervence either. why the above approaches are not adopted by Xen? Would anyone tell me the reason? Thanks a lot. -- The Following is added by the ISP. Please ignore them! 以下信息由邮件服务器提供商自动添加,与本邮件内容无关! _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel