[openib-general] Reserved L_Key API

[Michael S. Tsirkin]

Hello!
Quoting r. Roland Dreier (roland at topspin.com) "Re: [openib-general] Reserved L_Key API":
>     Fabian> I think you still need reg_phys_mr (or some way to get an
>     Fabian> RKEY) for kernel clients that do RDMA (SRP or kernel SDP,
>     Fabian> for example).  Something like an RKEY with translation off
>     Fabian> but PD enforcement (I don't think you want to get rid of
>     Fabian> PD enforcement for that kind of usage).  Given this, I
>     Fabian> would suggest keeping similar semantics as memory
>     Fabian> registration.
> 
> First, just to be clear, I'm not suggesting that we get rid of
> reg_phys_mr (although it would make sense for a low-level driver for
> a stupid TCA not to support the operation).
> 
> I don't think consumers ever really want to pass remote entities an
> R_Key with translation off (which would allow RDMA to arbitrary
> addreses).  I think the solution for creating R_Keys is FMRs (either
> Tavor-style or verbs extension-style).
> 
>  - R.

Why isnt PD protection sufficient?