Jonathan wrote:
I am looking for a sequence in which A maps to B and B ??? to C and the result would look like:
A -> B A -> C
Is there such an operation?
One possibility would be for B to request A to map the page on behalf of B. This would result in the above graph. I think your question relates to is there a possibility for A to avoid B mapping the page directly to B, i.e. is there a way for A to enforce that the above graph can only be created as such and particularly not in the form A - B - C. Do I get this right?
We are currently thinking about ways to restrict communication such, that this particular restriction is possible. The relevant question thereby is:
1) Should B be allowed to send messages to C, but no mappings? 2) Should B be allowed to send messages to C, but C not back to B?
In the second case we need a way to restrict mapping such, that the result is to map pages read only. Otherwise a read-writable page can be used as a back channel from C to B.
Marcus