On 06/20/2014 09:17 AM, Dave Hansen wrote:
> +/* These features, although they might be available in a CPU
> + * will not be used because the compile options to support
> + * them are not present.
> + *
> + * This code allows them to be checked and disabled at
> + * compile time withut an explicit #ifdef. Simply call
> + * cpu_has() or this_cpu_has().
> + * */
> +
> +#ifdef CONFIG_X86_INTEL_MPX
> +# define HAVE_MPX (1<<(X86_FEATURE_MPX & 31))
> +#else
> +# define HAVE_MPX 0
> +#endif
Urg. arch/x86/kvm/vmx.c has:
if (boot_cpu_has(X86_FEATURE_MPX))
rdmsrl(MSR_IA32_BNDCFGS, vmx->host_state.msr_host_...
And in that case we really _do_ want to test the actual CPU bit, despite
how we've configured MPX in the host kernel. We can call test_cpu_cap()
directly, I guess. But, all these interfaces are getting confusing. :(
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