What is the difference between Full, Para, and Hardware virtualization?

Question

I consider the topic of virtualization, it seems a little silly to ask this question, but I fully understand the basic concept, Wikipedia does provide some relevant information, but it’s not good for me to understand the basic concept. The concept will be from 2 to 3 lines, but neither I can find them on the network, nor in the book.

I will be glad if someone gives me a basic concept of these three types. I know virtualization well and understand it well, but these 3 types ...

Answer 1

• Paravirtualization is virtualization in which the guest operating system (the one that is virtualized) knows that he is a guest and, accordingly, has drivers that, instead of issuing hardware commands, simply issue commands directly to the host operating system. This also includes memory and thread management, which typically require inaccessible privileged instructions on the processor.

• Full virtualization is virtualization in which the guest operating system does not know that it is in a virtualized environment, and therefore the hardware is virtualized by the host operating system, so the guest can issue commands to what, in his opinion, is real equipment, but on these are simply simulated hardware devices created by the host.

• Hardware virtualization is a type of full virtualization where the microprocessor architecture has specific instructions for helping hardware virtualization. These instructions may allow you to configure a virtual context so that the guest can execute privileged instructions directly on the processor without affecting the host. This feature set is often called Hypervisor . If these instructions do not exist, full virtualization is still possible, however, this should be done using software methods such as Dynamic recompilation , where the host recompiles the privileged guests on the fly to be able to run in an unprivileged path on the host.

• There is also a combination of Para Virtualization and Full Virtualization called Hybrid Virtualization , where parts of the guest operating system use paravirtualization for certain hardware drivers, and the host uses full virtualization for other functions.This often gives excellent performance for the guest without having to completely paravirtualize the guest. An example of this: a guest uses full virtualization for privileged instructions in the kernel, but para-virtualization of I / O requests using a special driver in the guest system. Thus, the guest operating system does not have to be completely paravirtualized, as it is sometimes not available, but it can still have some paravirtualized functions, implementing special drivers for the guest.

Answer 2

In the case of hardware-related virtualization, virtualization is designed. The instruction set contains instructions for splitting the host. As an example, consider Intel VT-x technology. For the hypervisor to work directly with equipment without using any operating system to access it and ensure full virtualization