> We have done several rounds of discussion on linux-kernel about this so > far and the IB folks have not shown up to join in. I have tried to make > this as general as possible.
Sorry, this has been on my "things to look at" list for a while, but I haven't gotten a chance to really understand where things are yet. In general, this MMU notifier stuff will only be useful to a subset of InfiniBand/RDMA hardware. Some adapters are smart enough to handle changing the IO virtual -> bus/physical mapping on the fly, but some aren't. For the dumb adapters, I think the current ib_umem_get() is pretty close to as good as we can get: we have to keep the physical pages pinned for as long as the adapter is allowed to DMA into the memory region. For the smart adapters, we just need a chance to change the adapter's page table when the kernel/CPU's mapping changes, and naively, this stuff looks like it would work. Andrew, does that help? - R. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
