On Fri, 2016-12-09 at 08:34 +1100, Benjamin Herrenschmidt wrote:

As I mentioned earlier, probably 1 or 2 years ago, Dave made the
argument that shadowing through memory was necessary and precluded 2D
accel, though I don't fully remember the root of the argument. If that
is indeed not the case, then my main objection is lifted.

Things seem to change quickly as Daniel pointed out.

So ast and cirrus seem to still use a manual dirty tracking and
shadowing (though I'm not sure why), but the infrastructure for
that has moved from the drivers to the helpers.

bochs (qemu) doesn't seem to anymore from what I can see as it
doesn't have a ->dirty callback.

Cheers,
Ben.