Re: Regression: x86/mm: Add Secure Memory Encryption (SME) support

[Tom Lendacky <thomas.lendacky@amd.com>]

On 9/30/2017 5:36 PM, Tj wrote:
> With 4.14.0rc2 on an Intel CPU with an Nvidia GPU the proprietary nvidia
> driver (v340.102) fails to modpost due to:
> 
> FATAL: modpost: GPL-incompatible module nvidia.ko uses GPL-only symbol
> 'sme_me_mask'
> 
> I think this is due to:
> 
> config ARCH_HAS_MEM_ENCRYPT
>         def_bool y
> 

I think this is more likely because of CONFIG_AMD_MEM_ENCRYPT=y. If
CONFIG_AMD_MEM_ENCRYPT=n then sme_me_mask becomes a #define. I'm
assuming that changing the sme_me_mask in arch/x86/mm/mem_encrypt.c
from EXPORT_SYMBOL_GPL to EXPORT_SYMBOL fixes the issue?

Boris, is it a big deal to make this change if that's the issue?

Thanks,
Tom

> 
> I noticed that a grep of the built kernel for "sme_me_mask" shows the
> symbol imported into more than 300 modules on an Ubuntu mainline build
> of 4.14.0-041400rc2-lowlatency.
> 
> Should the new symbol be referenced so widely and how can it be
> prevented from being included in proprietary modules on systems that
> don't have SME even if the kernel is built with it enabled? >

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