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Subject: Re: [PATCH 4.9 43/92] x86/pti: Do not enable PTI on CPUs which are
 not vulnerable to Meltdown
To: Andi Kleen <ak@linux.intel.com>,
        Arjan van de Ven <arjan@linux.intel.com>
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From: Dave Hansen <dave.hansen@intel.com>
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Date: Tue, 13 Feb 2018 08:18:17 -0800
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On 02/13/2018 07:56 AM, Andi Kleen wrote:
> On Tue, Feb 13, 2018 at 07:09:44AM -0800, Arjan van de Ven wrote:
>>> So, any hints on what you think should be the correct fix here?
>> the patch sure looks correct to me, it now has a nice table for CPU IDs
>> including all of AMD (and soon hopefully the existing Intel ones that are not exposed to meltdown)
> I don't think the table is nice, it's a white list that would need
> to be maintained forever.

On Intel, we have that RDCL_NO bit in the ARCH_CAPABILITIES MSR going
forward to show that we are not vulnerable.  So, at least for Intel we
don't need to add new models forever.