Hypervisor- Virtual Machine

Hypervisor Part 2

Welcome back!

Today we will look at Full Virtualization, using either Software assisted full or Hardware assisted full.

Full Virtualization:
Virtual machine simulates hardware to allow an unmodified guest OS to be run in isolation. There are two types of Full virtualizations in the enterprise market. On both full virtualization types, the guest operating system’s source information will not be modified.
• Software assisted full virtualization
• Hardware assisted full virtualization

Software Assisted Full Virtualization:
Software-assisted full virtualization completely relies on binary translation to trap and virtualize the execution of sensitive, non-virtualizable instructions sets. It emulates the hardware using the software instruction sets. Due to binary translation, it is often criticized for performance issue. Here is the list of software which will fall under software assisted (BT).

• VMware workstation (32Bit guests)
• Virtual PC
• VirtualBox (32-bit guests)
• VMware Server

Hardware Assisted Full Virtualization:
Hardware-assisted full virtualization eliminates the binary translation and it directly interrupts with hardware using the virtualization technology which has been integrated on X86 processors since 2005 (Intel VT-x and AMD-V). Guest OS’s instructions might allow a virtual context execute privileged instructions directly on the processor, even though it is virtualized.
Here is the list of enterprise software which supports hardware-assisted – Full virtualization which falls under hypervisor type 1 (Bare metal).

• VMware ESXi /ESX
• KVM
• Hyper-V
• Xen

The following list fall under hypervisor type 2 (Hosted).
• VMware Workstation (64-bit guests only )
• Virtual Box (64-bit guests only )
• VMware Server (Retired )

Here’s a great write up explaining Para virtualization vs Full virtualization vs Hardware assisted Virtualization in more detail.

Stay tuned for Part 3 of the Hypervisor blog!