From: "H. Peter Anvin" <hpa@zytor.com>
To: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: NeilBrown <neilb@suse.de>,
james.t.kukunas@linux.intel.com,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [patch] x86, avx: don't use avx instructions with "noxsave" boot param
Date: Tue, 31 Jul 2012 09:43:22 -0700 [thread overview]
Message-ID: <50180B2A.6070602@zytor.com> (raw)
In-Reply-To: <1343752022.3696.602.camel@sbsiddha-desk.sc.intel.com>
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.
next prev parent reply other threads:[~2012-07-31 16:43 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-30 22:46 [patch] x86, avx: don't use avx instructions with "noxsave" boot param Suresh Siddha
2012-07-31 4:20 ` NeilBrown
2012-07-31 4:33 ` H. Peter Anvin
2012-07-31 16:27 ` Suresh Siddha
2012-07-31 16:43 ` H. Peter Anvin [this message]
2012-07-31 17:29 ` Suresh Siddha
2012-08-01 10:42 ` NeilBrown
2012-08-08 22:25 ` [tip:x86/urgent] x86, avx: don't use avx instructions with " noxsave" " tip-bot for Suresh Siddha
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