[PATCH v7 2/8] drm/ttm: Add ttm_bo_access

[Christian König]

Am 28.11.24 um 11:47 schrieb Rodrigo Vivi:
> On Wed, Nov 27, 2024 at 02:19:32PM +0100, Christian König wrote:
>> Am 26.11.24 um 18:46 schrieb Matthew Brost:
>>> Non-contiguous VRAM cannot easily be mapped in TTM nor can non-visible
>>> VRAM easily be accessed. Add ttm_bo_access, which is similar to
>>> ttm_bo_vm_access, to access such memory.
>>>
>>> v4:
>>>    - Fix checkpatch warnings (CI)
>>> v5:
>>>    - Fix checkpatch warnings (CI)
>>> v6:
>>>    - Fix kernel doc (Auld)
>>> v7:
>>>    - Move ttm_bo_access to ttm_bo_vm.c (Christian)
>>>
>>> Cc: Christian König <christian.koenig at amd.com>
>>> Reported-by: Christoph Manszewski <christoph.manszewski at intel.com>
>>> Suggested-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
>>> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
>>> Tested-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
>>> Reviewed-by: Matthew Auld <matthew.auld at intel.com>
>> Reviewed-by: Christian König <christian.koenig at amd.com>
> Thank you!
>
> Ack on get this through drm-xe-next?

I already agreed to that in the other mail to Matthew.

Regards,
Christian.

>
> drm-misc-maintainers?
>
>>> ---
>>>    drivers/gpu/drm/ttm/ttm_bo_vm.c | 40 ++++++++++++++++++++++++++-------
>>>    include/drm/ttm/ttm_bo.h        |  2 ++
>>>    2 files changed, 34 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> index 2c699ed1963a..f02d3966cc84 100644
>>> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> @@ -405,13 +405,25 @@ static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
>>>    	return len;
>>>    }
>>> -int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
>>> -		     void *buf, int len, int write)
>>> +/**
>>> + * ttm_bo_access - Helper to access a buffer object
>>> + *
>>> + * @bo: ttm buffer object
>>> + * @offset: access offset into buffer object
>>> + * @buf: pointer to caller memory to read into or write from
>>> + * @len: length of access
>>> + * @write: write access
>>> + *
>>> + * Utility function to access a buffer object. Useful when buffer object cannot
>>> + * be easily mapped (non-contiguous, non-visible, etc...). Should not directly
>>> + * be exported to user space via a peak / poke interface.
>>> + *
>>> + * Returns:
>>> + * @len if successful, negative error code on failure.
>>> + */
>>> +int ttm_bo_access(struct ttm_buffer_object *bo, unsigned long offset,
>>> +		  void *buf, int len, int write)
>>>    {
>>> -	struct ttm_buffer_object *bo = vma->vm_private_data;
>>> -	unsigned long offset = (addr) - vma->vm_start +
>>> -		((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node))
>>> -		 << PAGE_SHIFT);
>>>    	int ret;
>>>    	if (len < 1 || (offset + len) > bo->base.size)
>>> @@ -429,8 +441,8 @@ int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
>>>    		break;
>>>    	default:
>>>    		if (bo->bdev->funcs->access_memory)
>>> -			ret = bo->bdev->funcs->access_memory(
>>> -				bo, offset, buf, len, write);
>>> +			ret = bo->bdev->funcs->access_memory
>>> +				(bo, offset, buf, len, write);
>>>    		else
>>>    			ret = -EIO;
>>>    	}
>>> @@ -439,6 +451,18 @@ int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
>>>    	return ret;
>>>    }
>>> +EXPORT_SYMBOL(ttm_bo_access);
>>> +
>>> +int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
>>> +		     void *buf, int len, int write)
>>> +{
>>> +	struct ttm_buffer_object *bo = vma->vm_private_data;
>>> +	unsigned long offset = (addr) - vma->vm_start +
>>> +		((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node))
>>> +		 << PAGE_SHIFT);
>>> +
>>> +	return ttm_bo_access(bo, offset, buf, len, write);
>>> +}
>>>    EXPORT_SYMBOL(ttm_bo_vm_access);
>>>    static const struct vm_operations_struct ttm_bo_vm_ops = {
>>> diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h
>>> index 5804408815be..8ea11cd8df39 100644
>>> --- a/include/drm/ttm/ttm_bo.h
>>> +++ b/include/drm/ttm/ttm_bo.h
>>> @@ -421,6 +421,8 @@ void ttm_bo_unpin(struct ttm_buffer_object *bo);
>>>    int ttm_bo_evict_first(struct ttm_device *bdev,
>>>    		       struct ttm_resource_manager *man,
>>>    		       struct ttm_operation_ctx *ctx);
>>> +int ttm_bo_access(struct ttm_buffer_object *bo, unsigned long offset,
>>> +		  void *buf, int len, int write);
>>>    vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo,
>>>    			     struct vm_fault *vmf);
>>>    vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,