Thread (78 messages) 78 messages, 7 authors, 2016-12-09

Re: [RFC PATCH v3 04/20] x86: Handle reduction in physical address size with SME

From: Borislav Petkov <hidden>
Date: 2016-11-15 15:34:01
Also in: kvm, linux-arch, linux-iommu, linux-mm, lkml

On Tue, Nov 15, 2016 at 08:40:05AM -0600, Tom Lendacky wrote:
The feature may be present and enabled even if it is not currently
active.  In other words, the SYS_CFG MSR bit could be set but we aren't
actually using encryption (sme_me_mask is 0).  As long as the SYS_CFG
MSR bit is set we need to take into account the physical reduction in
address space.
But later in the series I see sme_early_mem_enc() which tests exactly
that mask.

And in patch 12 you have:

+       /*
+        * If memory encryption is active, the trampoline area will need to
+        * be in un-encrypted memory in order to bring up other processors
+        * successfully.
+        */
+       sme_early_mem_dec(__pa(base), size);
+       sme_set_mem_unenc(base, size);

What's up?

IOW, it all sounds to me like you want to have an sme_active() helper
and use it everywhere.

-- 
Regards/Gruss,
    Boris.

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