Re: [PATCH 04/10] s390/mm: force swiotlb for protected virtualization

Christian Borntraeger
2019-04-29T14:05:46Z

On 29.04.19 15:59, Halil Pasic wrote:
> On Fri, 26 Apr 2019 12:27:11 -0700
> Christoph Hellwig <hch@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
>
>