What technology does Yixun use for virtualization?

Virtualization is a broad term. In computers, it usually means that computing elements run on a virtual basis, not a real one. Virtualization technology can expand the capacity of hardware and simplify the reconfiguration process of software. CPU virtualization technology can use a single CPU to simulate the parallelism of multiple CPUs, allowing a platform to run multiple operating systems at the same time, and all applications can run in independent spaces without affecting each other, thus significantly improving the working efficiency of computers.

Virtualization technology is completely different from multitasking and hyper-threading technology. Multi-tasking means that multiple programs run in parallel in an operating system at the same time, while in virtualization technology, multiple operating systems can run at the same time, each operating system has multiple programs running, and each operating system runs on a virtual CPU or virtual host; But hyper-threading technology only simulates a single CPU to balance the performance of the program. These two simulated CPUs can't be separated and can only work together.

Virtualization technology is also different from the current software that can achieve the same virtual effect, such as VMware Workstation. It is a huge technological progress, which is reflected in reducing the related expenses of software virtual machines and supporting a wider range of operating systems.

Software-only virtualization solutions have many limitations. In many cases, the "guest" operating system communicates with hardware through VMM (Virtual Machine Monitor), and VMM decides its access to all virtual machines on the system. (Note that most processor and memory accesses are independent of VMM, which only involves certain events, such as page faults. ) In the pure software virtualization solution, the location of VMM in the software suite is the location of the operating system in the traditional sense, while the location of the operating system is the location of the application in the traditional sense. This extra communication layer needs binary conversion to simulate the hardware environment by providing interfaces with physical resources such as processor, memory, storage, graphics card and network card. This change will inevitably increase the complexity of the system. In addition, the support of guest operating system is limited by the capacity of virtual machine environment, which will hinder the deployment of some technologies, such as 64-bit guest operating system. In pure software solutions, the increased complexity of software stack means that these environments are difficult to manage, which will increase the difficulty of ensuring system reliability and security.