Comment by bri3d

With respect to 2), I don't think this should work architecturally even if the DRAM controller has knobs which can be accessed, because the guest's RAM should be encrypted with keys that can't be recovered in this way.

It's definitely a good research topic because there are a lot of moving pieces and having this kind of primitive might weaken one of them in a useful way, but at least at the top level, you couldn't just swap one guest's DRAM bank with another and get their confidential memory contents back this way.