vproc memory monitoring

[Pablo Graubner <graubner@xxxxxxxxxxxxxxxxxxxxxxxxx>]

Hi folks,

I am working on additional security mechanisms for the dragonfly  
vkernel and I want to monitor all in-memory copies (like intel asm  
"mov" and its derivates) of a running vproc in order to check if the  
vproc is allowed to copy data to the resp. memory segment.

My first approach was to use a technique similar to the implementation  
used in the emulation of the modified bit in the vkernel: If a vproc  
request a mapping for a page, the hostkernel disallows writes in the  
pagetable entry that it instantiates. Afterwards, during handling the  
resulting pagefault, the permissions of the resp. page should be  
checked.

I think it is obvious that this approach consumes significantly more  
time to handle every single memory copy of a vproc as a pagefault. Do  
you have any idea to monitor in-memory copies without such a  
performance overhead? As far as I know, there are some Linux binary  
analysis tools (like "Valgrind") wich could be used for memory- 
monitoring of a given process. Are there any similar approaches for  
the dragonfly vkernel which I could use?

Greetings,
Pablo