Re: [PATCH v3 4/4] x86/asm: Rewrite sync_core() to use IRET-to-self

2016-12-06 Thread Andy Lutomirski
On Mon, Dec 5, 2016 at 11:52 PM, Borislav Petkov wrote: > On Mon, Dec 05, 2016 at 01:32:43PM -0800, Andy Lutomirski wrote: >> Aside from being excessively slow, CPUID is problematic: Linux runs >> on a handful of CPUs that don't have CPUID. Use IRET-to-self >> instead. IRET-to-self works everywh

Re: [PATCH v3 4/4] x86/asm: Rewrite sync_core() to use IRET-to-self

2016-12-05 Thread Borislav Petkov
On Mon, Dec 05, 2016 at 01:32:43PM -0800, Andy Lutomirski wrote: > Aside from being excessively slow, CPUID is problematic: Linux runs > on a handful of CPUs that don't have CPUID. Use IRET-to-self > instead. IRET-to-self works everywhere, so it makes testing easy. > > For reference, On my lapto