Intel Prepares To Re-Enable ENQCMD On Linux After Being Disabled For "Broken Beyond Repair"

The ENQCMD functionality that is part of Intel's Data Streaming Accelerator with upcoming Xeon Scalable "Sapphire Rapids" processors was disabled earlier this year for being "broken beyond repair". But now ahead of Sapphire Rapids beginning to ramp up in the coming months, Intel open-source engineers believe they have improved the code that the ENQCMD instruction usage could be re-enabled for the Linux kernel.

Sent out on Friday by Intel's Fenghua Yu was the latest revision of getting the ENQCMD code cleaned up and re-enabled along with the PASID MSR handling. See this prior article for the background on the situation that led to the code getting disabled back in the summer.

Back in September fixes for ENQCMD were proposed albeit no action on those patches getting picked up by the mainline kernel and now as we prepare to end out the year this new patch series is that former work in updated form.

See the patch series for more details.