# Virtualization Airborne Trusted General Computing Technology
## 3 Key Technologies
### Virtualization Management Software Unit  
Depending on the type of virtual machine manager (VMM), the mainstream virtualization architecture types can be classified into full virtualization and paravirtualization. In full virtualization mode, the existing operating system can be directly run without modifying the resident operating system. Regarding its disadvantages, VMM needs to consume a certain amount of computing resources when the guest operating system does not know that it is running in a virtualization environment. Paravirtualization mode requires partial modification of the operating system, so that the system kernel can avoid some instructions that are difficult to virtualize, thereby effectively improving the performance of the entire system. Its disadvantage is that modification of the operating system source code is necessary.  
Considering that the \(\times\)86 processors have a specially optimized instruction set for controlling virtual process, they can support the hardware-assisted virtualization technology, so that the performance of full virtualization is improved to some extent. Thus,  
Figure 2: Architecture of high-performance processing and high-security hardware units.  
full virtualization design is adopted by the virtualization management software, and VM management is implemented by the microkernel VM management unit of the virtualization management layer. The VM management software unit uses the static configuration to bind the processor core, memory, and I/O devices. Through this design, the separate use of computing resources is realized and the distribution of computing resources between VMs is solved.  
The microkernel VM management software unit comprises a memory management module, VM management module, I/O management module, and processor architecture module. The functions of the various parts are as follows:  
1. VM management module: implements functions such as VM management, allocation and management of memory, I/O, processors and other hardware resources, and VM security encapsulation.
2. Processor architecture module: realizes processor virtualization; completes the translation of the processor instructions from the kernel unit of guest operating system and from the hardware facility layer; provides virtualized processing capabilities to VMs.
3. Memory management module: implements memory virtualization; provides virtualized memory resources to VMs. Memory virtualization is primarily implemented using extent page table (EPT) technology, where hardware automatically maps the virtual addresses within VMs to physical addresses and the physical addresses of VMs to physical addresses of hosts using the VM page tables. In this way, the virtual addresses of VMs are translated into the physical addresses of hosts.
4. I/O management module: implements virtual management of display devices, keyboards, mouse, gigabit Ethernet interfaces, USB devices, and other I/O devices in the hardware layer; provides virtualized device resources to VMs. Considering the usage frequency of I/O devices, software is used in the VMM to achieve their simulation, thereby providing VMs with support for these devices.