The current ptrace code is traversing the page table structures to

The current ptrace code is traversing the page table structures to
guest guest physical address, even when the guest paging is disabled.
The gdbserver-xen tries to access guest pdes & ptes to map memory of
hvm guest being debugged; and it gets a seg-fault because guest has not
setup it's paging yet. The attached patch adds guest paging state check,
so that the map_domain_va() can get the correct guest physical address
from guest va.

Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>