5 ms·
mitigations=off doesn't disable this effect.
by BeeOnRope 5y ago
mitigations=off doesn't disable this effect.
- darig 5y agomitigations=off does disable this effect.
- fouric 5y agoA citation or some kind of further explanation would be more valuable than an effective "no it doesn't" response.
- Chyzwar 5y agoIt disables kernel mitigation, not microcode mitigations.
- BeeOnRope 5y agoSorry, I explained it more detail elsewhere in this comments section. mitigations=off works at the OS kernel level to patch out some expensive aspects of what the kernel can do (possibly in concert with the CPU but driven by the kernel). This issue a microcode change that affects the CPU behavior without any intervention by the kernel, so mitigations=off doesn't help.
- Wowfunhappy 5y agoDo the microcode changed alone, without kernel mitigations, negatively impact performance?
- BeeOnRope 5y agoYes. There is no kernel mitigation associated with this issue and it is not in the Spectre class of vulnerabilities. It is purely a microcode fix for an "old-school" data dependent timing issue.
- marcyb5st 5y agoThanks! I wasn't aware of that!