For a 64-bit PowerPC target, qemu correctly implements translation
through the segment lookaside buffer.  Likewise it supports the
slbmte instruction which is used to load entries into the SLB.

However, it does not emulate the slbmfee and slbmfev instructions
which read SLB entries back into registers.  Because these are
only occasionally used in guests (mostly for debugging) we get
away with it.

However, given the recent SLB cleanups, it becomes quite easy to
implement these, and thereby allow, amongst other things, a guest
Linux to use xmon's command to dump the SLB.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>