Logging Access to HDD

[Sebastian Biedermann <biedermann@seceng.informatik.tu-darmstadt.de>]

Dear List,

I´m working in research and I tought this list could be
a good adress for my questions.

I want to log the disk accesses of the virtual hvm instances running in Xen.
That means for the start I want to log the write querys of a running
domU instance in the dom0 instance.

So I´m trying to modify the Xen 3.2.1 source code,
but actually I was not able to find a good entry point to do this.

For now, I want to log the disk accesses of a running windows 7 domU 
instance.
The best what could happenis that I could see even the source and target 
of a hdd write query.

Does anyone have an idea how I could do this on a good way?
Which Xen source file / function should I modify? Where is the best 
entry point to do this?

Thank you a lot.

-- 
Sebastian Biedermann