Re: [wlug] Another Day, Another Intel CPU Security Hole: Lazy State

On Fri, 15 Jun 2018 11:05:21 +1200, Peter Reutemann quoted:

'Saving and restoring this state when switching from one application to another takes time. As a performance optimization, this may be done "lazily" (i.e., when needed) and that is where the problem hides.'

Contrariwise <https://www.theregister.co.uk/2018/06/13/intel_lazy_fpu_state_security_flaw/>: The fix is to employ a mechanism called eager FPU state restore, which modern Linux, Windows and other kernels use. These mitigations do not carry a performance hit – in fact, eager state switching can increase performance.