When shadowing a nested guest, a check is performed and no shadowing is
attempted if the nested guest is already shadowed.
The existing check was incomplete; fix it by also checking whether the
leaf DAT table entry in the existing shadow gmap has the same protection
as the one specified in the guest DAT entry.
Fixes: e38c884df9 ("KVM: s390: Switch to new gmap")
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
6f93d1ed6f