I/o virtualization technology - UIO framework

Catalog

UIO Framework — User mode network protocol stack scheme

UIO Framework Kernel Module（User Space I/O, User mode I/O Framework kernel module ）, yes Kernel The user mode provided I/O Driver framework . be based on UIO Framework Can write data message to bypass Kernel Network Stack, Go straight into User Space Kernel module for processing （e.g. DPDK IGB_UIO）.

however ,UIO There are also shortcomings , for example ： I won't support it DMA（ Not subject to IOMMU The protection of the ）、 Interrupt support is limited 、 need Root Permission operation, etc , So pass DMA Transmitting large amount of data I/O equipment , Such as ： By Passthrougth Network card of 、 Video card and other devices , Can't use UIO Framework Of .

UIO The implementation mechanism of ： Expose a file interface to user mode , When registering a UIO Equipment time , A system file will appear /dev/uioX, To read and write the file is to read and write the memory of the network card device . besides , The control of network card equipment can also be realized through /sys/class/uio Read and write the following files to complete .

Here's the picture ：

• mmap() Interface ： Register space for mapping devices .
• read() Interface ： For waiting