Re: [Xen-devel] [PATCH 10/24] xen: mask XSAVE from cpuid

Andi Kleen
2009-03-17T15:55:45Z

> well the choice fundamentally is
> 1) Have correct applications work, even though you might not always get
> all new features that the hardware could have done.. at the expense
> that someone who wants to do horrible things can
> 2) Have all latest features always there, but break correctly written
> apps/oses every 2 years.

I'm not sure there will be that much breakage. It seems more like
a theoretical danger.

>
> I'd go for option 1 any day of the week, hands down.
> Esp if the "cpu cloaking" kind of things really disable the
> instructions... but even without.

With cpu cloaking and disabling unknown instructions it would be fine
to go conservative. But that's not what is being proposed.

-Andi

--
ak@linux.intel.com -- Speaking for myself only.