Hello Jesper, On Mon, Dec 05, 2016 at 03:31:32PM +0100, Jesper Dangaard Brouer wrote: > Hi all, > > This is my design for how to safely handle RX zero-copy in the network > stack, by using page_pool[1] and modifying NIC drivers. Safely means > not leaking kernel info in pages mapped to userspace and resilience > so a malicious userspace app cannot crash the kernel. > > Design target > ============= > > Allow the NIC to function as a normal Linux NIC and be shared in a > safe manor, between the kernel network stack and an accelerated > userspace application using RX zero-copy delivery. > > Target is to provide the basis for building RX zero-copy solutions in > a memory safe manor. An efficient communication channel for userspace > delivery is out of scope for this document, but OOM considerations are > discussed below (`Userspace delivery and OOM`_). Sorry, if this reply is a bit off-topic. I'm working on implementation of RX zero-copy for virtio and I've dedicated some thought about making guest memory available for physical NIC DMAs. I believe this is quite related to your page_pool proposal, at least from the NIC driver perspective, so I'd like to share some thoughts here. The idea is to dedicate one (or more) of the NIC's queues to a VM, e.g. using macvtap, and then propagate guest RX memory allocations to the NIC using something like new .ndo_set_rx_buffers method. What is your view about interface between the page_pool and the NIC drivers? Have you considered using "push" model for setting the NIC's RX memory? > > -- > Jesper Dangaard Brouer > MSc.CS, Principal Kernel Engineer at Red Hat > LinkedIn: http://www.linkedin.com/in/brouer > > Above document is taken at GitHub commit 47fa7c844f48fab8b > https://github.com/netoptimizer/prototype-kernel/commit/47fa7c844f48fab8b > -- Sincerely yours, Mike. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>