Writing to arbritary cannonical addresses

[Charles Gonçalves <charles.fg@xxxxxxxxx>]

Hello Guys,

I'm trying to reproduce old exploit behaviors in a simplistic way:  create an hypercall to write a buffer to a specific MFN. 

At first, I thought that updating an l1 page in a valid VA in guest kernel space would do the trick. 

But for addresses outside the  Guest-defined use (0x0000000000000000 - 0x00007fffffffffff ) is a no go! 

I get a page fault with  'reserved bit in page table' warning message.

Now I'm trying to write to the address inside the hypervisor code, but not sure how to do it.  

Any comments or tips on this?

Atenciosamente,

Charles Ferreira Gonçalves