Paul's comment on my first approach to fix the h2g usage in
page_find_alloc finally open my eyes about what the code is actually
supposed to do:

With the help of h2g_valid we can no cleanly check if a freshly allocate
page (for host usage) is guest-reachable and, in case it is, mark it
reserved in the guest's address range.
Signed-off-by: NJan Kiszka <jan.kiszka@web.de>
Signed-off-by: NKirill A. Shutemov <kirill@shutemov.name>
Acked-by: NEdgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5957 c046a42c-6fe2-441c-8c8c-71466251a162