Meltdown and Spectre Linux Kernel Status
RHEL&#x2F;CentOS state:<p>Red Hat built their own mitigation for Meltdown and Spectre and were the first distribution to have an updated kernel right when the embargo was lifted.<p>As far as I can tell, their meltdown mitigations are similar to what&#x27;s in the upstream kernel now, and the Spectre mitigations relies on Intel&#x27;s new MSRs (the microcode update that had since been retracted - new microcode_ctl packages remove it).<p>Interestingly, you can enable&#x2F;disable the mitigations at runtime with Red Hat, which is useful for performance testing. I found no way to do this with the upstream kernel.<p>I&#x27;m not happy that Intel, Google, Red Hat and a few others have known about the bug for months and the upstream kernel devs are scrambling to build mitigations and still don&#x27;t support the microcode mitigations. Google apparently patched their stuff in September, while everyone else is left out in the cold. This is a real mess. Surely there must be a better way than telling a few select companies?<p>The Red Hat guys in particular surely would&#x27;ve loved to collaborate with the upstream kernel. Must be frustrating not to be able to tell anyone.