Re: [RFC PATCH] x86/arch_prctl: Add ARCH_SET_XCR0 to mask XCR0 per-thread

[Andi Kleen]

Patch seems pointless if you can already control CPUID, which rr
supports. Just disable AVX512 in CPUID. All code using AVX should check
cpuid (or will fail anyways). 

-Andi