Why not turn it off entirely?
Another benefit of the salting mechanism is that it allows the administrator to define groups of VMs that are trusted in which sharing will be performed.
disclaimer: I work at VMware and wrote the salting code.
Seems the savings would be somewhat offset by having your whole business destroyed because its easy to crack.
It's just that in the face of defective hardware, it's not safe. But this is not surprising, because nothing is safe, so it isn't particularly a criticism of page sharing. This specific attack may have used it, but Rowhammer is a powerful tool. This is not the only way it can be used; it is merely an exemplar.