On Mon, May 02, 2005 at 02:59:26PM -0700, Fab Tillier wrote: > > From: Dror Goldenberg [mailto:[EMAIL PROTECTED] > > > > You're welcomed to measure. I think that FMRs will be the fastest way > > to create mapping. Faster than MWs. > > The reason I asked is SDP went down the FMR path, but that can only work > properly if the remote peer is trusted. I don't know if this assumption > should be made - the same way that we shouldn't trust user-mode processes, > we shouldn't trust remote user-mode processes. It is possible for an SDP > implementation to be in user-mode. Thus a window exists where a user-mode > process on a remote node could corrupt memory via RDMA to stale (but still > cached in the HCA) regions. The pages that used to represent those regions > could well have been freed and reallocated. This design decision led me to > believe that MWs were significantly slower than FMRs (hence the tradeoff > with system security). > > Note that I'm not fully versed in the SDP implementation, so if it addresses > this, great!
Nope, not addressed. A rogue SDP peer implementation could write into memory that is no longer being used as an active AIO buffer. One way to at least isolate the risk is to add a callback for when the mapping is changed/released and then unlock the buffer. At least the memory will not be used for anything else, even if it could still result in corruption of that buffer... -Libor _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
