[Xen-devel] Getting Machine Physical address from page-fault CR2...

["Petersson, Mats" <Mats.Petersson@xxxxxxx>]

I'm trying to write a piece of code to check writes to MMIO-space (as
part of the Configuration Change Verifier, as discussed at the Security
Mini-summit at Summer Xen-Summit in San Jose some weeks back). 

This code needs to check if a physical address matches some list of
known physical addresses... My problem right now is that the method I
thought would work for translating the value in CR2 (after some other
initial checking - like that the page is actually present), doesn't
work... I tried something along the lines of:

traps.c: do_page_fault():
pa = shadow_gva_to_gpa(current, addr); /* addr = read_cr2() earlier in
the code */

It appeats that current->arch.shadow.mode is sometimes NULL, which isn't
what I expected... 

Is there some other (better?) way to achieve this? I mean aside from
walking the page-table?

--
Mats



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