On Thu, Aug 15, 2019 at 09:59:03PM +0100, Andrew Cooper wrote: > If you're virtualised, the write to MSR_AMD64_CPUID_FN_1 almost > certainly won't take effect, which means userspace will still be able to > see the bit. msr_clear_bit() has a return value. We should check it before doing anything further. I hope the HV actually signals the write success/failure properly so that we get a correct return value. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.