In my earlier post , I had mentioned that child vm’s will only communicate with parent partition where the windows server 2008 operating system is installed, but how ?. Microsoft has developed user mode applications and the kernel mode drivers to handle the communication between the vm’s.
Kernel Mode Section
Few major kernel components of Hyper-v that engineers has to remember is
a) Virtualization Service Provider (VSP)
b) Virtualization Service Client (VSC)
How does the VM’s communicate ?
Answer: VM’s communicate using kernel mode driver called VMBUS, and remember that the communication is not between the VM’s and hardware , rather the communication is between VM’s and parent partition. VMBus is used to for I/O communication.
How does VM’s share physical hardware resources ?
Answer: Physical hardware resources are accessed / shared through VMBus. There are 2 main components involved such as VSP and VSC. VSP resides on parent partition and VSC resides on all the VM’s, both VSP and VSC communicate over VMBus. A simpler architectural diagram is shown below.
The above diagram shows the kernel pieces responsible for communication across the VM’s , in our next post we will see the user mode applications provided by Microsoft for managing these VM’s and also tools to monitor these VM’s