Re: [RFC PATCH v2 19/20] x86: Access the setup data through debugfs un-encrypted

From: Borislav Petkov
Date: Wed Sep 14 2016 - 10:51:10 EST

On Wed, Sep 14, 2016 at 09:29:41AM -0500, Tom Lendacky wrote:
> This is still required because just using the __va() would still cause
> the mapping created to have the encryption bit set. The ioremap call
> will result in the mapping not having the encryption bit set.

I meant this:

Wouldn't simply clearing the SME mask work?

#define __va(x) ((void *)(((unsigned long)(x)+PAGE_OFFSET) & ~sme_me_mask))

Or are you saying, one needs the whole noodling through ioremap_cache()
because the data is already encrypted and accessing it with sme_me_mask
cleared would simply give you the encrypted garbage?


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