Re: [RFC PATCH v2 12/32] x86: Add early boot support when running with SEV active

From	Borislav Petkov <bp@suse.de>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH v2 12/32] x86: Add early boot support when running with SEV active
Date	2017-03-16 11:20 +0100
Message-ID	<tlAFH-5fe-3@gated-at.bofh.it> (permalink)
References	(1 earlier) <tj6Vs-6eP-13@gated-at.bofh.it> <tj6Vs-6eP-11@gated-at.bofh.it> <tj8Xf-7Er-17@gated-at.bofh.it> <tj9gC-7KS-13@gated-at.bofh.it> <tlAFH-5fe-5@gated-at.bofh.it>
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On Fri, Mar 10, 2017 at 10:35:30AM -0600, Brijesh Singh wrote:
> We could update this patch to use the below logic:
> 
>  * CPUID(0) - Check for AuthenticAMD
>  * CPID(1) - Check if under hypervisor
>  * CPUID(0x80000000) - Check for highest supported leaf
>  * CPUID(0x8000001F).EAX - Check for SME and SEV support
>  * rdmsr (MSR_K8_SYSCFG)[MemEncryptionModeEnc] - Check if SMEE is set

Actually, it is still not clear to me *why* we need to do anything
special wrt SEV in the guest.

Lemme clarify: why can't the guest boot just like a normal Linux on
baremetal and use the SME(!) detection code to set sme_enable and so
on? IOW, I'd like to avoid all those checks whether we're running under
hypervisor and handle all that like we're running on baremetal.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--

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Re: [RFC PATCH v2 12/32] x86: Add early boot support when running  with SEV active Borislav Petkov <bp@suse.de> - 2017-03-16 11:20 +0100
  Re: [RFC PATCH v2 12/32] x86: Add early boot support when running  with SEV active Borislav Petkov <bp@suse.de> - 2017-03-16 16:20 +0100
    Re: [RFC PATCH v2 12/32] x86: Add early boot support when running  with SEV active Borislav Petkov <bp@suse.de> - 2017-03-16 17:30 +0100

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