Re: capability address space and virtualizing objects

Neal H. Walfield wrote:
> This interface poses a problem for virtualization.  One of the goals
> of Viengoos is that all interfaces be virtualizable.  This has (so
> far) included the ability to fully virtualize kernel objects.
> Virtualizing an object is done by way of a message buffer, on which
> the same interface is implemented as the object that is being
> virtualized.
> 
> This means that to virtualize a cappage, it must also be possible to
> virtualize cappage indexing.  Imagine that to find the source message
> buffer in the above msg_buf_enqueue invocation includes traversing a
> virtualized cappage.  That is, after translating some bits of the
> address, the kernel encounters a message buffer.  This means that
> instead of a kernel-implemented cappage, a message buffer is
> encountered while traversing the address space.  Instead of failing,
> the kernel should conceptually index the message buffer.  This means
> sending it an index message with the residual address.

Erm, are you sure that this kind of feature is required? Allowing the 
address translation process to be extended in such a way is a somewhat 
orthogonal issue imho (though of course there are interrelations as you 
show) opening a completely new realm of problems. I'm not convinced that 
you want to do that. Are there compelling use case?
-- 
-ness-