Intel's Project ACRN To Upstream More Code With Linux 5.12

Written by Michael Larabel in Virtualization on 10 February 2021 at 08:43 AM EST. Add A Comment
Announced nearly three years ago by Intel was the ACRN reference hypervisor framework intended for IoT/embedded use-cases with real-time capabilities and safety-critical computing. More of the kernel bits to this "Big Little Hypervisor for IoT Development" are set to see mainline with the imminent Linux 5.12 kernel cycle.

Back in 2019 with Linux 5.3 was initial ACRN guest support. Ultimately this ACRN Hypervisor has been continuing along not only with Intel but also organizations like LG, APTIV, Neusoft, and others under the "Project ACRN" umbrella. Now with the upcoming Linux 5.12 cycle, more of the ACRN hypervisor support is set to land.

Over the past few years the ACRN hypervisor has continued advancing. This hypervisor has even found its way into some automobiles with the likes of Clear Linux and Android. The hypervisor focus during this time has remained with a focus on real-time and safety critical needs. Compared to say KVM and Xen, ACRN has a smaller footprint, BSD licensed, and has hard/soft real-time capabilities. Besides Linux/Android guests, VxWorks, Windows, and other operating systems are also supported. ACRN goes without some features like VM migration or vCPU migration that aren't relevant to their embedded use-cases.

Given Intel's involvement, ACRN is optimized and focused for running on Intel platforms.

Project ACRN has been focused on supporting Linux LTS kernel releases while with Linux 5.12 the hypervisor support is seeing its initial introduction. This week the ACRN code began landing in char-misc-next ahead of the 5.12 merge window. The focus for Linux 5.12 appears to be on its Hypervisor Service Module (HSM) as the middle-layer for the ACRN user-space and Service VM OS kernel to communicate with the hypervisor and manager different user VMs. More code will likely be upstreamed during the coming kernel cycles.

The initial ACRN hypervisor code for Linux 5.12 can be found via this char-misc-next query. This documentation commit provides an overview of the current architecture.

Learn more about Project ACRN at Aside from what's been upstreamed so far or now pending, the rest of the Project ACRN work is housed over on GitHub.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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