On 09/06/17 19:43, Boris Ostrovsky wrote: > On 06/09/2017 02:36 PM, Tom Lendacky wrote: >>> basis, although (as far as I am aware) Xen as a whole would be able to >>> encompass itself and all of its PV guests inside one single SME >>> instance. >> Yes, that is correct. Thinking more about this, it would only be possible if all the PV guests were SME-aware and understood not to choke when it finds a frame with a high address bit set. I expect the only viable way to implement this (should we wish) is to have PV guests explicitly signal support (probably via an ELF note), after which it needs to know about the existence of SME, the meaning of the encrypted bit in PTEs, and to defer all configuration responsibility to Xen. ~Andrew
