From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [RFC PATCH v1 09/28] x86/efi: Access EFI data as encrypted when
 SEV is active
Date: Thu, 22 Sep 2016 14:04:27 -0500
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Cc: Brijesh Singh <brijesh.singh@amd.com>, <simon.guinot@sequanux.org>,
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To: Borislav Petkov <bp@suse.de>, Paolo Bonzini <pbonzini@redhat.com>
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On 09/22/2016 12:07 PM, Borislav Petkov wrote:
> On Thu, Sep 22, 2016 at 05:05:54PM +0200, Paolo Bonzini wrote:
>> Which paragraph?
> 
> "Linux relies on BIOS to set this bit if BIOS has determined that the
> reduction in the physical address space as a result of enabling memory
> encryption..."
> 
> Basically, you can enable SME in the BIOS and you're all set.

That's not what I mean here.  If the BIOS sets the SMEE bit in the
SYS_CFG msr then, even if the encryption bit is never used, there is
still a reduction in physical address space.

Transparent SME (TSME) will be a BIOS option that will result in the
memory controller performing encryption no matter what. In this case
all data will be encrypted without a reduction in physical address
space.

Thanks,
Tom

> 

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