Re: [PATCH 3/4] drm/amdgpu: drm/amdgpu: Handle IOMMU enabled case

[Andrey Grodzovsky <andrey.grodzovsky@amd.com>]

Ping

Andrey

On 2021-08-25 11:36 a.m., Andrey Grodzovsky wrote:
>
> On 2021-08-25 2:43 a.m., Christian König wrote:
>>
>>
>> Am 24.08.21 um 23:01 schrieb Andrey Grodzovsky:
>>> Handle all DMA IOMMU group related dependencies before the
>>> group is removed and we try to access it after free.
>>>
>>> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
>>> ---
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c |  2 +
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 50 
>>> ++++++++++++++++++++++
>>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h    |  1 +
>>>   3 files changed, 53 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> index 0b5764aa98a4..288a465b8101 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>> @@ -3860,6 +3860,8 @@ void amdgpu_device_fini_hw(struct 
>>> amdgpu_device *adev)
>>>         amdgpu_device_ip_fini_early(adev);
>>>   +    amdgpu_ttm_clear_dma_mappings(adev);
>>> +
>>>       amdgpu_gart_dummy_page_fini(adev);
>>>         amdgpu_device_unmap_mmio(adev);
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>> index 446943e32e3e..f73d807db3b0 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>> @@ -64,6 +64,7 @@
>>>   static int amdgpu_ttm_backend_bind(struct ttm_device *bdev,
>>>                      struct ttm_tt *ttm,
>>>                      struct ttm_resource *bo_mem);
>>> +
>>>   static void amdgpu_ttm_backend_unbind(struct ttm_device *bdev,
>>>                         struct ttm_tt *ttm);
>>>   @@ -2293,6 +2294,55 @@ static ssize_t amdgpu_iomem_write(struct 
>>> file *f, const char __user *buf,
>>>       return result;
>>>   }
>>>   +void amdgpu_ttm_clear_dma_mappings(struct amdgpu_device *adev)
>>
>> I strongly think that this function should be part of TTM. Something 
>> like ttm_device_force_unpopulate.
>
>
> Yes, this something I also wanted but see bellow
>
>
>>
>>> +{
>>> +    struct ttm_device *bdev = &adev->mman.bdev;
>>> +    struct ttm_resource_manager *man;
>>> +    struct ttm_buffer_object *bo;
>>> +    unsigned int i, j;
>>> +
>>> +    spin_lock(&bdev->lru_lock);
>>> +    for (i = TTM_PL_SYSTEM; i < TTM_NUM_MEM_TYPES; ++i) {
>>> +        man = ttm_manager_type(bdev, i);
>>> +        if (!man || !man->use_tt)
>>> +            continue;
>>> +
>>> +        while (!list_empty(&man->pinned)) {
>>> +            bo = list_first_entry(&man->pinned, struct 
>>> ttm_buffer_object, lru);
>>> +            /* Take ref against racing releases once lru_lock is 
>>> unlocked */
>>> +            ttm_bo_get(bo);
>>> +            list_del_init(&bo->lru);
>>> +            spin_unlock(&bdev->lru_lock);
>>> +
>>> +            if (bo->ttm) {
>>> +                amdgpu_ttm_backend_unbind(bo->bdev, bo->ttm);
>
>
> amdgpu_ttm_backend_unbind is needed to be called separately from 
> ttm_tt_unpopulate to take care of code
> flows that do dma mapping though the gart bind and not through 
> ttm_tt_populate, Since it's inside amdgpu
> i had to place the entire function in amdgpu. Any suggestions ?
>
> Andrey
>
>
>>> + ttm_tt_destroy_common(bo->bdev, bo->ttm);
>>
>> Then you can also cleanly use ttm_tt_unpopulate here, cause this will 
>> result in incorrect statistics inside TTM atm.
>>
>> Regards,
>> Christian.
>>
>>> +            }
>>> +
>>> +            ttm_bo_put(bo);
>>> +            spin_lock(&bdev->lru_lock);
>>> +        }
>>> +
>>> +        for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
>>> +            while (!list_empty(&man->lru[j])) {
>>> +                bo = list_first_entry(&man->lru[j], struct 
>>> ttm_buffer_object, lru);
>>> +                ttm_bo_get(bo);
>>> +                list_del_init(&bo->lru);
>>> +                spin_unlock(&bdev->lru_lock);
>>> +
>>> +                if (bo->ttm) {
>>> +                    amdgpu_ttm_backend_unbind(bo->bdev, bo->ttm);
>>> +                    ttm_tt_destroy_common(bo->bdev, bo->ttm);
>>> +                }
>>> +                ttm_bo_put(bo);
>>> +                spin_lock(&bdev->lru_lock);
>>> +            }
>>> +        }
>>> +    }
>>> +    spin_unlock(&bdev->lru_lock);
>>> +
>>> +}
>>> +
>>>   static const struct file_operations amdgpu_ttm_iomem_fops = {
>>>       .owner = THIS_MODULE,
>>>       .read = amdgpu_iomem_read,
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h 
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>>> index e69f3e8e06e5..02c8eac48a64 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>>> @@ -190,6 +190,7 @@ bool amdgpu_ttm_tt_is_readonly(struct ttm_tt *ttm);
>>>   uint64_t amdgpu_ttm_tt_pde_flags(struct ttm_tt *ttm, struct 
>>> ttm_resource *mem);
>>>   uint64_t amdgpu_ttm_tt_pte_flags(struct amdgpu_device *adev, 
>>> struct ttm_tt *ttm,
>>>                    struct ttm_resource *mem);
>>> +void amdgpu_ttm_clear_dma_mappings(struct amdgpu_device *adev);
>>>     void amdgpu_ttm_debugfs_init(struct amdgpu_device *adev);
>>