Hardware Virtualization

Hardware Virtualization

1. Define

   • Full Virtualization
     • All OS and thier hosted apps are run on top of virtual hardware
     • VMM (at RING 0 ) decouples guest OS from underlying physical hardware
     • Each VM has a VMM for Binary Translation
   • Para Virtualization
     • Uses Hypercalls to handle instructions at run time
     • Guest Runs at Ring 0
   • Hardware Assisted
     • Acheived by hypervisor aware CPU to handle privileged instructions
       • Reduced Virtualization Overhead
       • CPU and Memory virtualization support is provided in Hardware
       • AMD-V , Intel -VT

2. Ring Layers

   • Ring 0
     • VMM(Virtual Macine Monitor)
   • Ring 1
     • Guest OS
   • Ring 2
   • Ring 3
     • User Apps
   • Offered By x86
   • For FULL Virtualization

3. Possible via Hypervisor

   • manages the physical hardware resource which is shared between the customer and the provider

4. Benifits

   • Economical
   • Efficient Backup and Reovery
   • Disaster Recovery

5. Challenges

   • Requires placing virtualization layer below OS layer
   • Difficult to capture and translate priviledged OS instruction at runtime