Intel Readies "PFRUT" For Linux 5.17 To Allow Updating System Firmware Without Rebooting

Written by Michael Larabel in Intel on 28 December 2021 at 07:09 PM EST. 9 Comments
Intel open-source engineers have prepared "PFRUT" support for Platform Firmware Runtime Updates for allowing (U)EFI capsule updates to be performed on capable systems without rebooting the system in order to eliminate downtime.

Intel has worked on PFRUT that is now part of the ACPI specification for allowing platform firmware components to be updated on-the-fly without the need to restart the system. The intent of this is for servers where they need to be "available 100% of the time" and other cases where downtime must be kept to an aboslute minimum. This "pfr_update" driver set for Linux 5.17 introduction seems to be primarily geared for being able to update system firmware in cases of critical bugs or security issues in a timely manner while not introducing any new downtime.

Back in September I wrote about Intel engineers working on such functionality for the linux kernel and around this ACPI specification. At the time it was referred to as Intel "Seamless Update" as presumably their marketing name. The patches for this new driver are just referencing it as ACPI PFRUT without calling it Seamless Update, so we'll see if that branding has changed or Intel just trying to keep this ACPI driver completely vendor agnostic.

Another change with this new patch series is PFRUT where as previously it mentioned PFRU.... The "T" being added now is for Telemetry. As part of this enablement is now a Platform Firmware Runtime Telemetry driver too. This driver is for reading telemetry data from the firmware in a standardized manner.

This patch on Monday introduced the new pfr_update driver and followed by the telemetry driver. Also added is a simple PFRUT tool for user-space for demonstrating the firmware updates and telemetry access.

These patches were picked up by the Linux power management's "linux-next" branch meaning it's material for the next kernel cycle, which will be Linux 5.17 with that merge window opening in mid-January.

For those interested in more information on Intel's run-time firmware updating, from August is the Intel Management Mode Firmware Runtime Update specification. We'll see ahead if desktop systems end up supporting it or is reserved just for server class hardware.
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