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From: "H. Peter Anvin" <hpa@zytor.com>
To: Borislav Petkov <bp@alien8.de>, X86 ML <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>, Borislav Petkov <bp@suse.de>
Subject: Re: [PATCH 3/4] x86, head_32: Remove second CPUID detection from default_entry
Date: Mon, 11 Feb 2013 09:21:54 -0800	[thread overview]
Message-ID: <511928B2.6000302@zytor.com> (raw)
In-Reply-To: <20130211171541.GD2683@pd.tnic>

On 02/11/2013 09:15 AM, Borislav Petkov wrote:
> On Mon, Feb 11, 2013 at 07:49:14AM -0800, H. Peter Anvin wrote:
>> What about CPUs with inconsistent cpuid levels? Yes, they can and do
>> happen, as we discussed on IRC.
>
> Yes, this should still work. We're doing the EFLAGS.ID dance right at
> the beginning of default_entry on each cpu and cache cpuld level in
> new_cpu_data for the time we're in this code.
>
> What this particular patch removes is the yet-another EFLAGS.ID dance
> which we IMHO unnecessarily did after enabling paging.
>
> So basically nothing changes wrt handling inconsistent cpuid levels and
> MSR mis-programming - we still should be taking care of those cases.
>

Cool.  I misread your 0/4 cover and hadn't quite dug into the details yet.

	-hpa


-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  reply	other threads:[~2013-02-11 17:22 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-11 14:22 [PATCH 0/4 -v3] x86, head_32: Some cleanups Borislav Petkov
2013-02-11 14:22 ` [PATCH 1/4] x86, head_32: Remove i386 pieces Borislav Petkov
2013-02-13  0:07   ` [tip:x86/asm] " tip-bot for Borislav Petkov
2013-02-11 14:22 ` [PATCH 2/4] x86: Detect CPUID support early at boot Borislav Petkov
2013-02-13  0:09   ` [tip:x86/asm] " tip-bot for Borislav Petkov
2013-02-11 14:22 ` [PATCH 3/4] x86, head_32: Remove second CPUID detection from default_entry Borislav Petkov
2013-02-11 15:49   ` H. Peter Anvin
2013-02-11 17:15     ` Borislav Petkov
2013-02-11 17:21       ` H. Peter Anvin [this message]
2013-02-13  0:10   ` [tip:x86/asm] " tip-bot for Borislav Petkov
2013-02-11 14:22 ` [PATCH 4/4] x86, head_32: Give the 6 label a real name Borislav Petkov
2013-02-13  0:11   ` [tip:x86/asm] " tip-bot for Borislav Petkov
2013-02-11 16:56 ` [PATCH 0/4 -v3] x86, head_32: Some cleanups H. Peter Anvin

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