Messages in this thread | | | Date | Tue, 31 Jul 2012 09:43:22 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [patch] x86, avx: don't use avx instructions with "noxsave" boot param |
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On 07/31/2012 09:27 AM, Suresh Siddha wrote: > On Mon, 2012-07-30 at 21:33 -0700, H. Peter Anvin wrote: >> I'm wondering if we shouldn't just kill the affected CPUID bits if osxsave is off... > > Yes, I considered clearing AVX bit (and any future xsave feature bits) > as part of the parsing "noxsave" parameter in x86_xsave_setup(). > > But thought checking for osxsave was more explicit and there are not > many places using avx code. Also, this follows the SDM guidelines and > sets a nice precedent for someone (app's) to follow in future. > > I am ok either way! >
My main reason for thinking that it would be good to clear the bits is that it plays a lot nicer with alternatives and with static_cpu_has().
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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