Re: [PATCH v2 12/32] drm/gpusvm: Introduce vram_only flag for VRAM allocation

["Ghimiray, Himal Prasad" <himal.prasad.ghimiray@intel.com>]

On 17-04-2025 08:37, Matthew Brost wrote:
> On Mon, Apr 07, 2025 at 03:46:59PM +0530, Himal Prasad Ghimiray wrote:
>> This commit adds a new flag, vram_only, to the drm_gpusvm structure. The
>> purpose of this flag is to ensure that the get_pages function allocates
>> memory exclusively from the device's VRAM. If the allocation from VRAM
>> fails, the function will return an -EFAULT error.
>>
>> Suggested-by: Matthew Brost <matthew.brost@intel.com>
> 
> Again this is included in [1] with you remaining as the author.
> 
> Anyways:
> Reviewed-by: Matthew Brost <matthew.brost@intel.com>

Thanks

> 
> [1] https://patchwork.freedesktop.org/series/147846/
> 
>> Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
>> ---
>>   drivers/gpu/drm/drm_gpusvm.c | 5 +++++
>>   include/drm/drm_gpusvm.h     | 2 ++
>>   2 files changed, 7 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c
>> index 2451c816edd5..149ac56eff70 100644
>> --- a/drivers/gpu/drm/drm_gpusvm.c
>> +++ b/drivers/gpu/drm/drm_gpusvm.c
>> @@ -1454,6 +1454,11 @@ int drm_gpusvm_range_get_pages(struct drm_gpusvm *gpusvm,
>>   				goto err_unmap;
>>   			}
>>   
>> +			if (ctx->vram_only) {
>> +				err = -EFAULT;
>> +				goto err_unmap;
>> +			}
>> +
>>   			addr = dma_map_page(gpusvm->drm->dev,
>>   					    page, 0,
>>   					    PAGE_SIZE << order,
>> diff --git a/include/drm/drm_gpusvm.h b/include/drm/drm_gpusvm.h
>> index df120b4d1f83..8093cc6ab1f4 100644
>> --- a/include/drm/drm_gpusvm.h
>> +++ b/include/drm/drm_gpusvm.h
>> @@ -286,6 +286,7 @@ struct drm_gpusvm {
>>    * @in_notifier: entering from a MMU notifier
>>    * @read_only: operating on read-only memory
>>    * @devmem_possible: possible to use device memory
>> + * @vram_only: Use only device memory
>>    *
>>    * Context that is DRM GPUSVM is operating in (i.e. user arguments).
>>    */
>> @@ -294,6 +295,7 @@ struct drm_gpusvm_ctx {
>>   	unsigned int in_notifier :1;
>>   	unsigned int read_only :1;
>>   	unsigned int devmem_possible :1;
>> +	unsigned int vram_only :1;
>>   };
>>   
>>   int drm_gpusvm_init(struct drm_gpusvm *gpusvm,
>> -- 
>> 2.34.1
>>