Intel Introduces "Hyper DMA-BUF" To Exchange Buffers Between VMs

Published on Tuesday were a set of 60 kernel patches rolling out "hyper_dmabuf" as a means of allowing DMA-BUF buffers to be exchanged between virtual machines.

These initial "RFC" (request for comments) patches allow for the DMA-BUF exchange between multiple VMs on the same system. KVM and Xen are the hypervisor support targets while for these initial patches the code is wired up for Xen.

The DMA-BUF framework is designed to provide a generic means of sharing buffers between multiple devices. DMA-BUF is commonly used in Linux multi-GPU configurations as well as sharing buffers between multiple blocks on the same SoC and buffer sharing between drivers in a standardized manner. But up until now I haven't seen much of a demand or use-case for inter-VM sharing of buffers... The patches don't elaborate on their planned use-case: there is already Xen GVT support for Intel GPU acceleration and passing buffers from the VM to host, but perhaps due to lack of coffee this early morning, failing to think of why they would just be wanting to do DMA-BUF buffer sharing between VMs.

Anyhow, those wishing to learn more about Hyper DMA-BUF can do so via this patch series.