Nouveau - Apr 2021 - [PATCH 3/8] drm/amdgpu: Implement mmap as GEM object function

On 2021-04-07 3:34 p.m., Felix Kuehling wrote:
> On 2021-04-07 7:25 a.m., Christian K?nig wrote:
>>>>>> +??? /*
>>>>>> +???? * Don't verify access for KFD BOs. They
don't have a GEM
>>>>>> +???? * object associated with them.
>>>>>> +???? */
>>>>>> +??? if (bo->kfd_bo)
>>>>>> +??????? goto out;
>>>>> Who does the access verification now?
>>>> This is somewhat confusing.
>>>>
>>>> I took this check as-is, including the comment, from
amdgpu's
>>>> verify_access function. The verify_access function was called
by
>>>> ttm_bo_mmap. It returned 0 and ttm_bo_mmap did the mapping.
>>> This is probably a left-over from when we mapped BOs using
/dev/kfd. We
>>> changed this to use /dev/dri/renderD* a long time ago to fix CPU 
>>> mapping
>>> invalidations on memory evictions. I think we can let GEM do the
access
>>> check.
>>
>> Ok, good to know.
>>
>> Thomas can you remove the extra handling in a separate prerequisite 
>> patch?
>>
>> If anybody then bisects to this patch we at least know what to do to 
>> get it working again.
>
> FWIW, I ran KFDTest test with this shortcut removed on current 
> amd-staging-drm-next + my HMM patch series, and it didn't seem to 
> cause any issues.
Wait, I celebrated too soon. I was running the wrong kernel. I do see 
some failures where access is being denied. I need to do more debugging 
to figure out what's causing that.

Regards,
 ? Felix

>
> Regards,
> ? Felix
>
>
>>
>> Regards,
>> Christian.

Hi

Am 07.04.21 um 21:49 schrieb Felix Kuehling:
> On 2021-04-07 3:34 p.m., Felix Kuehling wrote:
>> On 2021-04-07 7:25 a.m., Christian K?nig wrote:
>>>>>>> +??? /*
>>>>>>> +???? * Don't verify access for KFD BOs. They
don't have a GEM
>>>>>>> +???? * object associated with them.
>>>>>>> +???? */
>>>>>>> +??? if (bo->kfd_bo)
>>>>>>> +??????? goto out;
>>>>>> Who does the access verification now?
>>>>> This is somewhat confusing.
>>>>>
>>>>> I took this check as-is, including the comment, from
amdgpu's
>>>>> verify_access function. The verify_access function was
called by
>>>>> ttm_bo_mmap. It returned 0 and ttm_bo_mmap did the mapping.
>>>> This is probably a left-over from when we mapped BOs using
/dev/kfd. We
>>>> changed this to use /dev/dri/renderD* a long time ago to fix
CPU
>>>> mapping
>>>> invalidations on memory evictions. I think we can let GEM do
the access
>>>> check.
>>>
>>> Ok, good to know.
>>>
>>> Thomas can you remove the extra handling in a separate prerequisite
>>> patch?
>>>
>>> If anybody then bisects to this patch we at least know what to do
to
>>> get it working again.
>>
>> FWIW, I ran KFDTest test with this shortcut removed on current 
>> amd-staging-drm-next + my HMM patch series, and it didn't seem to 
>> cause any issues.
> 
> Wait, I celebrated too soon. I was running the wrong kernel. I do see 
> some failures where access is being denied. I need to do more debugging 
> to figure out what's causing that.
OK, thanks for looking into this. I'll wait a bit before sending out the 
new patchset.

Best regards
Thomas
> 
> Regards,
>  ? Felix
> 
> 
>>
>> Regards,
>> ? Felix
>>
>>
>>>
>>> Regards,
>>> Christian. 
-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 N?rnberg, Germany
(HRB 36809, AG N?rnberg)
Gesch?ftsf?hrer: Felix Imend?rffer

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Hi

Am 07.04.21 um 21:49 schrieb Felix Kuehling:
> On 2021-04-07 3:34 p.m., Felix Kuehling wrote:
>> On 2021-04-07 7:25 a.m., Christian K?nig wrote:
>>>>>>> +??? /*
>>>>>>> +???? * Don't verify access for KFD BOs. They 
don't have a GEM
>>>>>>> +???? * object associated with them.
>>>>>>> +???? */
>>>>>>> +??? if (bo->kfd_bo)
>>>>>>> +??????? goto out;
>>>>>> Who does the access verification now?
>>>>> This is somewhat confusing.
>>>>>
>>>>> I took this check as-is, including the comment, from
amdgpu's
>>>>> verify_access function. The verify_access function was
called by
>>>>> ttm_bo_mmap. It returned 0 and ttm_bo_mmap did the mapping.
>>>> This is probably a left-over from when we mapped BOs using
/dev/kfd.
We
>>>> changed this to use /dev/dri/renderD* a long time ago to fix
CPU
>>>> mapping
>>>> invalidations on memory evictions. I think we can let GEM do
the access
>>>> check.
>>>
>>> Ok, good to know.
>>>
>>> Thomas can you remove the extra handling in a separate prerequisite
>>> patch?
>>>
>>> If anybody then bisects to this patch we at least know what to do
to
>>> get it working again.
>>
>> FWIW, I ran KFDTest test with this shortcut removed on current 
>> amd-staging-drm-next + my HMM patch series, and it didn't seem to 
>> cause any issues.
> 
> Wait, I celebrated too soon. I was running the wrong kernel. I do see 
> some failures where access is being denied. I need to do more debugging 
> to figure out what's causing that.
Any news here? I saw the patch at [1], which removes the kfd_bo test. 
Can I assume that the series addresses the issue?

Best regards
Thomas

[1] https://patchwork.freedesktop.org/patch/427516/?series=88822&rev=1
> 
> Regards,
>  ? Felix
> 
> 
>>
>> Regards,
>> ? Felix
>>
>>
>>>
>>> Regards,
>>> Christian. 
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 N?rnberg, Germany
(HRB 36809, AG N?rnberg)
Gesch?ftsf?hrer: Felix Imend?rffer

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