Handling a MEM_EVENT_REASON_CR3

[Razvan Cojocaru <rzvncj@gmail.com>]

Hello,

a few questions about receiving a MEM_EVENT_REASON_CR3 even in dom0 
userspace:

1. If I call

xc_set_hvm_param(xci, domain_id,
                  HVM_PARAM_MEMORY_EVENT_CR3,
                  HVMPME_onchangeonly);

that only triggers a CR3 event if the new value that the guest writes to 
CR3 is different from the existing value, is that assumption correct?

2. mem_event.h says that if "CR3 was hit: gfn is CR3 value". I'm 
assuming that gfn is the _new_ value, and that the old value is 
unavailable, is that also correct?

3. Is it possible to, upon intercepting the CR3 write, write a 
_different_ value to CR3, instead of gfn?

Thanks,
Razvan Cojocaru