Re: [PATCH v1] drm/ttm: Refcount allocated tail pages

[Dmitry Osipenko]

On 8/15/22 13:05, Christian König wrote:
> Am 15.08.22 um 11:54 schrieb Dmitry Osipenko:
>> Higher order pages allocated using alloc_pages() aren't refcounted and
>> they
>> need to be refcounted, otherwise it's impossible to map them by KVM. This
>> patch sets the refcount of the tail pages and fixes the KVM memory
>> mapping
>> faults.
>>
>> Without this change guest virgl driver can't map host buffers into guest
>> and can't provide OpenGL 4.5 profile support to the guest. The host
>> mappings are also needed for enabling the Venus driver using host GPU
>> drivers that are utilizing TTM.
>>
>> Based on a patch proposed by Trigger Huang.
> 
> Well I can't count how often I have repeated this: This is an absolutely
> clear NAK!
> 
> TTM pages are not reference counted in the first place and because of
> this giving them to virgl is illegal.

A? The first page is refcounted when allocated, the tail pages are not.

> Please immediately stop this completely broken approach. We have
> discussed this multiple times now.

Could you please give me a link to these discussions?

-- 
Best regards,
Dmitry