This fixes https://bugs.launchpad.net/qemu/+bug/786209:
When the DRQ_STAT bit is set, the IDE core permits both data reads
and data writes, regardless of whether the current transfer was
initiated as a read or write.
This potentially leaks uninitialized host memory into the guest,
if, before doing anything else to an IDE device, the guest begins a
write transaction (e.g. WIN_WRITE), but then *reads* from the IO
port instead of writing to it.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
40c4ed3f95