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Subject: Re: [PATCH v6 10/34] x86, x86/mm, x86/xen, olpc: Use __va() against
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To: Tom Lendacky <thomas.lendacky@amd.com>, linux-arch@vger.kernel.org,
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From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Date: Thu, 8 Jun 2017 17:17:29 -0400
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On 06/08/2017 05:02 PM, Tom Lendacky wrote:
> On 6/8/2017 3:51 PM, Boris Ostrovsky wrote:
>>
>>>
>>>> What may be needed is making sure X86_FEATURE_SME is not set for PV
>>>> guests.
>>>
>>> And that may be something that Xen will need to control through either
>>> CPUID or MSR support for the PV guests.
>>
>>
>> Only on newer versions of Xen. On earlier versions (2-3 years old) leaf
>> 0x80000007 is passed to the guest unchanged. And so is MSR_K8_SYSCFG.
>
> The SME feature is in leaf 0x8000001f, is that leaf passed to the guest
> unchanged?

Oh, I misread the patch where X86_FEATURE_SME is defined. Then all
versions, including the current one, pass it unchanged.

All that's needed is setup_clear_cpu_cap(X86_FEATURE_SME) in
xen_init_capabilities().


-boris