Linux 5.19 Lands New Intel IFS Driver For Helping To Detect Faulty Silicon

Among many Intel driver improvements in Linux 5.19, Intel's new "In-Field Scan" (IFS) driver has now premiered in the mainline kernel for testing future processors against any silicon issues prior to deployment or as the processors age.

Platform Drivers x86 maintainer Hans de Goede of Red Hat submitted the v5.19 feature updates to which were merged last night. Most notable with the "PDx86" updates for this next kernel version is the introduction of the Intel In-Field Scan driver.

Intel In-Field Scan I originally wrote about back in March as allowing for "in-field" tests on future CPUs. Intel IFS aims to provide circuit-level tests on CPUs for detecting hardware problems not caught by parity or ECC checks. Intel IFS tests could be carried out prior to deploying new systems/servers into production or routinely carrying out said tests over the duration of the system's lifespan to ensure no hardware-level issues materialize over time. At least for now In-Field Scan is focused on Intel server processors and the needs of hyperscalers, OEMs, and other large Intel Linux server deployments rather than for client products.

The new IFS Linux driver just provides the necessary infrastructure for running the tests and not test cases themselves. The Intel circuit-level tests are loaded as a binary similar to the Intel CPU microcode. The tests are specific to particular CPU family / model / stepping combinations and authenticated prior to being loaded within the CPU's secure memory. I haven't seen Intel publish any of these IFS tests yet so it remains to be seen how exhaustive their circuit-level tests will be or other details, but presumably will learn more once Xeon Sapphire Rapids has its formal launch later this year.

Intel In-Field Scan

Interacting with Intel IFS can be done via sysfs. The tests can be loaded via /sys/devices/system/cpu/ifs/reload. Triggering the IFS tests to then execute on all available CPU cores can then be carried out via writing to /sys/devices/system/cpu/ifs/run_test. The IFS driver also allows testing individual specific CPU cores as well via sysfs. After testing, the results are written to /sys/devices/system/cpu/ifs/status for reporting if all CPU cores passed / failed / untested.

Other platform drivers x86 changes for Linux 5.19 include AMD PMC driver improvements, AMD HSMP v5 message support for future AMD EPYC CPUs, and other routine updates. The Gigabyte WMI driver has also added support for the Z490 AORUS ELITE AC, X570 AORUS ELITE WIFI, and B660 GAMING X DDR4 motherboards.