Re: [Xen-devel] Unreachable code about cpu features

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 28.03.13 at 15:40, Choonho Son <choonho.son@xxxxxxxxx> wrote:
> I still have some questions about cpu flags.
> - Reference:
> http://lists.xen.org/archives/html/xen-devel/2013-03/msg00891.html 
> 
> I printed the values about following code:
>  if (!~(opt_cpuid_mask_ecx & opt_cpuid_mask_edx &
>                opt_cpuid_mask_ext_ecx & opt_cpuid_mask_ext_edx &
>                opt_cpuid_mask_xsave_eax))
>                 return;
> 
> Above code is always true, so the next "switch" code is not reachable.
> Is it correct code?

Of course it is - you just need to make use of the respective
command line options to get those variable have other than their
default (initial) values. It is intentional for the code to do nothing
without command line option saying so.

Jan


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