On Thu, Sep 22, 2016 at 02:49:22PM -0500, Tom Lendacky wrote:

quoted

I thought that reduction is the reservation of bits for the SME mask.

What other reduction is there?

There is a reduction in physical address space for the SME mask and the
bits used to aid in identifying the ASID associated with the memory
request. This allows for the memory controller to determine the key to
be used for the encryption operation (host/hypervisor key vs. an SEV
guest key).

Ok, I think I see what you mean: you call SME mask the bit in CPUID
Fn8000_001F[EBX][5:0], i.e., the C-bit, i.e. sme_me_mask. And the other
reduction is the key ASID, i.e., CPUID Fn8000_001F[EBX][11:6], i.e.
sme_me_loss.

I think we're on the same page - I was simply calling everything SME
mask because both are together in the PTE:

"Additionally, in some implementations, the physical address size of the
processor may be reduced when memory encryption features are enabled,
for example from 48 to 43 bits."

-- 
Regards/Gruss,
    Boris.

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