That is a really really bad thing ins't it, completely giving away the isolation at the very lowest level?
How come this happens though. Saving/restoring the full set of registers is easy right, everyone knows the full list. Do they try limit the set of register to save/restore depending on the operation to improve performance thus causing the bug? It seems like it should be one of the most validated piece of a hypervisor code given that isolation is one of biggest selling point specially now with containers doing the resource sharing bit more efficiently it seems.
How come this happens though. Saving/restoring the full set of registers is easy right, everyone knows the full list. Do they try limit the set of register to save/restore depending on the operation to improve performance thus causing the bug? It seems like it should be one of the most validated piece of a hypervisor code given that isolation is one of biggest selling point specially now with containers doing the resource sharing bit more efficiently it seems.