Hardware Virtualization

Hardware Virtualization

1. Definition

   • Abstracting the physical hardware layer using hypervisor or VMM

2. Advantages

   • Lower Cost
   • Efficient Resource Utilization
   • Increase IT flexibility
   • Increased UPtime

3. Types Of Virtualization

   • Full Virtualization
     • Full virtualization provides support for unmodified guest operating systems
       • unmodified refers to operating system kernels which have not been altered to run on a hypervisor and therefore still execute privileged operations as though running in ring 0 of the CPU
   • Para Virtualization
     • Under paravirtualization the kernel of the guest operating system is modified specifically to run on the hypervisor.
   • Hardware Assisted Virtualization
     • Hardware-assisted virtualization is a technology that allows for a CPU instruction set communication in which the VMM runs in a new root level mode below the OS kernel level

4. Protection Rings

   • Definition
     • Protection Rings provides logical space for the levels of permissions and execution
   • Types
     • Ring3 (least privileged), Ring2, Ring1, Ring0 (most privileged)

5. Comparison para vs full virtualization

   • Para-> virtual machine does not implement full isolation of OS but rather provides a different API which is utilized when OS is subjected to alteration. Full-> , virtual machine permit the execution of the instructions with running of unmodified OS in an entire isolated way.
   • Para-> more secure. Full-> Less Secure
   • Para-> uses hypercalls at compile time for operations. Full-> uses binary translation and direct approach as a technique for operations.
   • Para-> Fast and less portable and less compatible. Full-> Slow and more portable and more compatible