Xen Virtualization(cont.)

Shared info pages
-provides information to the kernel at boot up
-functionality analogous to BIOS
-also used during runtime to get the overall state of the system.
Also going through grant table concept which allows the memory pages to be shared or transferred between domains.
Also trying out tcp client server implementation for passing config info.

Xen Virtualization(cont)

Studied about xenstore and xenbus for inter-domain comm.
xenstore, analogous to proc fs, used to store info by 1 domain which can be accessed by info from another domain
xenbus is an abstraction of actual bus which is used to communicate config and staus info between domains
xenstore-write , xenstore-read commands are available to access xenstore directly
probe function is triggered for a driver when a value corresponding to the device is written on to the xenstore.
Also cont. the tcp server ,client thing

Xen Virtualization (cont)

Netback started a module
trying a tcp server to start up in init_module
so that a external tcp client can communicate with it to pass
config info..

Also studied the netback - netfront mechanism
evt-channel mechanism.

Xen Virtualization(cont)

- checking out hyper call mechanism to find out where exactly the dom0 control is passed to hypervisor
- the working of event channel
- the driver part is loaded as a module so checking out ways to pass the config parameters when the module loads.

Xen Virtual;ization (cont)

Code study of xm (command line tool for xen)
code study of xend (python daemon for parsing and processing xm commands)
used pdb for the debugging purpose.
code studyof dom0 part where xend sends config info.
using printk for understanding the code flow.
Algo
--------
understanding the flowchat.
answered qns like
1. who assigns sequence no for packets
2.sum of credits is constant or not after redistribution