Messages in this thread | | | Subject | Re: [RFC PATCH v1 09/28] x86/efi: Access EFI data as encrypted when SEV is active | From | Tom Lendacky <> | Date | Thu, 22 Sep 2016 14:04:27 -0500 |
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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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