[$] Controlling device peer-to-peer access from user space

Post Syndicated from corbet original https://lwn.net/Articles/782489/rss

The recent addition of
support for direct (peer-to-peer) operations between PCIe devices
in the
kernel has opened the door for different use cases. The initial work
concentrated on in-kernel support and the NVMe subsystem; it also
added support for memory regions that can be used for such transfers.
Jérôme Glisse recently proposed
two extensions
that would allow the mapping of those regions into user
space and mapping device files between two devices.
The resulting discussion surprisingly led to consideration of the
future of core kernel structures dealing with memory management.