Unbinding Linux kernel drivers to allow userland IO through VFIO has a number of disadvantages such as another large touchy code base to deal with the hardware, loss of standard Linux tools (ifconfig, ethtool, tcpdump, SNMPd...) and impossibility to accelerate container networking. Mediated device introduced in Linux kernel 4.10 for GPUs and provisions for additional devices hold the promise of collaboration between kernel drivers and userland application in need of direct datapath steering. Packet frameworks such as OpenDataPlane, DPDK, VPP and Netmap may benefit from leveraging mediated devices. This sessions intends to discuss the practicalities and security aspects of such an approach and how ODP and DPDK communities may collaborate on userland IO.
Topics covered: - slides: brief review of IOMMU, IOMMU groups and default group, DMA API and VFIO - slides: An overview of the proposed approach and challenges will be presented in the form of slides. - demo: crypto IO from userland and selected code walk through (generic device access) - demo: network IO from userland and selected code walk through (net_device specific extensions)
Speakers: François-Frédéric Ozog