Linux Virtualization - Apr 2019 - [PATCH 04/10] s390/mm: force swiotlb for protected virtualization

On Fri, Apr 26, 2019 at 08:32:39PM +0200, Halil Pasic
wrote:
> +EXPORT_SYMBOL_GPL(set_memory_encrypted);
> +EXPORT_SYMBOL_GPL(set_memory_decrypted);
> +EXPORT_SYMBOL_GPL(sev_active);
Why do you export these?  I know x86 exports those as well, but
it shoudn't be needed there either.

On Fri, 26 Apr 2019 12:27:11 -0700
Christoph Hellwig <hch at infradead.org> wrote:
> On Fri, Apr 26, 2019 at 08:32:39PM +0200, Halil Pasic wrote:
> > +EXPORT_SYMBOL_GPL(set_memory_encrypted);
> 
> > +EXPORT_SYMBOL_GPL(set_memory_decrypted);
> 
> > +EXPORT_SYMBOL_GPL(sev_active);
> 
> Why do you export these?  I know x86 exports those as well, but
> it shoudn't be needed there either.
> 
I export these to be in line with the x86 implementation (which
is the original and seems to be the only one at the moment). I assumed
that 'exported or not' is kind of a part of the interface definition.
Honestly, I did not give it too much thought.

For x86 set_memory(en|de)crypted got exported by 95cf9264d5f3 "x86, drm,
fbdev: Do not specify encrypted memory for video mappings" (Tom
Lendacky, 2017-07-17). With CONFIG_FB_VGA16=m seems to be necessary for x84.

If the consensus is don't export: I won't. I'm fine one way or the
other.
@Christian, what is your take on this?

Thank you very much!

Regards,
Halil

On 29.04.19 15:59, Halil Pasic wrote:
> On Fri, 26 Apr 2019 12:27:11 -0700
> Christoph Hellwig <hch at infradead.org> wrote:
> 
>> On Fri, Apr 26, 2019 at 08:32:39PM +0200, Halil Pasic wrote:
>>> +EXPORT_SYMBOL_GPL(set_memory_encrypted);
>>
>>> +EXPORT_SYMBOL_GPL(set_memory_decrypted);
>>
>>> +EXPORT_SYMBOL_GPL(sev_active);
>>
>> Why do you export these?  I know x86 exports those as well, but
>> it shoudn't be needed there either.
>>
> 
> I export these to be in line with the x86 implementation (which
> is the original and seems to be the only one at the moment). I assumed
> that 'exported or not' is kind of a part of the interface
definition.
> Honestly, I did not give it too much thought.
> 
> For x86 set_memory(en|de)crypted got exported by 95cf9264d5f3 "x86,
drm,
> fbdev: Do not specify encrypted memory for video mappings" (Tom
> Lendacky, 2017-07-17). With CONFIG_FB_VGA16=m seems to be necessary for
x84.
> 
> If the consensus is don't export: I won't. I'm fine one way or
the other.
> @Christian, what is your take on this?
If we do not need it today for anything (e.g. virtio-gpu) then we can get rid
of the exports (and introduce them when necessary).
> 
> Thank you very much!
> 
> Regards,
> Halil
> 
>