Thomas Gleixner <t...@linutronix.de> writes: > When entering idle, it's a good oportunity to verify that the TSC_ADJUST > MSR has not been tampered with (BIOS hiding SMM cycles). If tampering is > detected, emit a warning and restore it to the previous value.
idle entry is a time critical code path too, because idle periods are often very short. rdmsr is a us+ at least. You'll likely make workloads that do a lot of short sleeps noticeable slower. If anything load limit it aggressively. BTW I don't think this situation of SMM tampering with TSC is common anyways, so it may be simply not worth checking, or perhaps only with a debug boot option. -Andi
