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microcode update for Xeon E3 V6 #41

Open amazingAmy opened 4 years ago

amazingAmy commented 4 years ago

Is the microcode update for Xeon E3 V6 available to fix the L1TF and special register buffer data sampling? WHAT is the latest microcode version for the Xeon E3 V6? Is 0xd6 the latest version?

bsdice commented 4 years ago

Yes 0xD6 from 2020-04-23 seems to be the latest, but I recommend 0xCA because my personal Linux workstation started crashing with "illegal opcode" errors on 0xD6 with an E3-1275v6 on a Supermicro X11SAT board. Took me several days to nail the microcode as culprit down. In the end I had a "crashkernel" in place to catch the bug post-mortem, but the system always seemed too far gone for that to work. In hindsight an indication that either hardware is dying or a microcode update introduced a serious problem.

hmh commented 4 years ago

"Illegal opcode" errors after loading a microcode update really sounds like you're doing what is known [in Linux] as a "late microcode update". Check your configuration and distro instructions, please ensure you are only doing "early" loading of microcode updates: the "late" microcode updates are prone to failures like the one you describe.

Hint: the kernel logs the safer "early microcod update" as one of the first things during boot. Try the command "journalctl -k -b | head" and check for something like "microcode: microcode updated early to revision..." in the output. If not using systemd, try "dmesg | head" soon after booting. You might need to run these commands as root depending on your distro.

If switching to early updates doesn't fix it (or it was already doing early updates), you really need the update in firmware so that it is updated even earlier and so that any possible incompatibility issues are sorted by the system vendor. Request from Supermicro support a BIOS/firmware update that includes up-to-date microcode.

bsdice commented 4 years ago

Thanks for the nice reminder @hmh and yes of course I update microcode earliest possible using "initrd /intel-ucode.img" in systemd-boot, before kernel and boot ramdisk is loaded. Log message about early update is present. With D6 it takes 0-3 days and this workstation will hang so hard that it will not even kexec the crashkernel (I debugged this process with forced kernel panics - it works). The problem is gone with CA, with nothing else changed. Hence my cautionary note to Amy.

whpenner commented 3 years ago

Please update to the latest microcode updates. This issue should be resolved.