Re: [PATCH v2 5/8] drm/amdgpu: accommodate DOMAIN/PL_DOORBELL

[Shashank Sharma <shashank.sharma@amd.com>]

On 14/02/2023 19:31, Christian König wrote:
> Am 14.02.23 um 17:15 schrieb Shashank Sharma:
>> From: Alex Deucher <alexander.deucher@amd.com>
>>
>> This patch adds changes:
>> - to accommodate the new GEM domain DOORBELL
>> - to accommodate the new TTM PL DOORBELL
>>
>> to manage doorbell allocations as GEM Objects.
>>
>> V2: Addressed reviwe comments from Christian
>>      - drop the doorbell changes for pinning/unpinning
>>      - drop the doorbell changes for dma-buf map
>>      - drop the doorbell changes for sgt
>>      - no need to handle TTM_PL_FLAG_CONTIGUOUS for doorbell
>>
>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>> Signed-off-by: Shashank Sharma <shashank.sharma@amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 11 ++++++++++-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    | 11 ++++++++++-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h    |  1 +
>>   3 files changed, 21 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> index b48c9fd60c43..ff9979fecfd2 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
>> @@ -147,6 +147,14 @@ void amdgpu_bo_placement_from_domain(struct 
>> amdgpu_bo *abo, u32 domain)
>>           c++;
>>       }
>>   +    if (domain & AMDGPU_GEM_DOMAIN_DOORBELL) {
>> +        places[c].fpfn = 0;
>> +        places[c].lpfn = 0;
>> +        places[c].mem_type = AMDGPU_PL_DOORBELL;
>> +        places[c].flags = 0;
>> +        c++;
>> +    }
>> +
>
> Mhm, do we need to increase AMDGPU_BO_MAX_PLACEMENTS?
>
> I think the answer is *no* since mixing DOORBELL with CPU, GTT or VRAM 
> placement doesn't make sense, but do we enforce that somewhere?
I am not sure why do we need that ?
>
>>       if (domain & AMDGPU_GEM_DOMAIN_GTT) {
>>           places[c].fpfn = 0;
>>           places[c].lpfn = 0;
>> @@ -466,7 +474,7 @@ static bool amdgpu_bo_validate_size(struct 
>> amdgpu_device *adev,
>>           goto fail;
>>       }
>>   -    /* TODO add more domains checks, such as AMDGPU_GEM_DOMAIN_CPU */
>> +    /* TODO add more domains checks, such as AMDGPU_GEM_DOMAIN_CPU,  
>> AMDGPU_GEM_DOMAIN_DOORBELL */
>
> Should we enforce that user space can only allocate 1 page doorbells?
>
Should we add a per-PID basis check ?

- Shashank

>>       return true;
>>     fail:
>> @@ -1014,6 +1022,7 @@ void amdgpu_bo_unpin(struct amdgpu_bo *bo)
>>       } else if (bo->tbo.resource->mem_type == TTM_PL_TT) {
>>           atomic64_sub(amdgpu_bo_size(bo), &adev->gart_pin_size);
>>       }
>> +
>
> Unrelated change.

Noted

- Shashank

>
> Regards,
> Christian.
>
>>   }
>>     static const char *amdgpu_vram_names[] = {
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> index 0e8f580769ab..e9dc24191fc8 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>> @@ -128,6 +128,7 @@ static void amdgpu_evict_flags(struct 
>> ttm_buffer_object *bo,
>>       case AMDGPU_PL_GDS:
>>       case AMDGPU_PL_GWS:
>>       case AMDGPU_PL_OA:
>> +    case AMDGPU_PL_DOORBELL:
>>           placement->num_placement = 0;
>>           placement->num_busy_placement = 0;
>>           return;
>> @@ -500,9 +501,11 @@ static int amdgpu_bo_move(struct 
>> ttm_buffer_object *bo, bool evict,
>>       if (old_mem->mem_type == AMDGPU_PL_GDS ||
>>           old_mem->mem_type == AMDGPU_PL_GWS ||
>>           old_mem->mem_type == AMDGPU_PL_OA ||
>> +        old_mem->mem_type == AMDGPU_PL_DOORBELL ||
>>           new_mem->mem_type == AMDGPU_PL_GDS ||
>>           new_mem->mem_type == AMDGPU_PL_GWS ||
>> -        new_mem->mem_type == AMDGPU_PL_OA) {
>> +        new_mem->mem_type == AMDGPU_PL_OA ||
>> +        new_mem->mem_type == AMDGPU_PL_DOORBELL) {
>>           /* Nothing to save here */
>>           ttm_bo_move_null(bo, new_mem);
>>           goto out;
>> @@ -586,6 +589,11 @@ static int amdgpu_ttm_io_mem_reserve(struct 
>> ttm_device *bdev,
>>           mem->bus.offset += adev->gmc.vram_aper_base;
>>           mem->bus.is_iomem = true;
>>           break;
>> +    case AMDGPU_PL_DOORBELL:
>> +        mem->bus.offset = mem->start << PAGE_SHIFT;
>> +        mem->bus.offset += adev->doorbell.doorbell_aper_base;
>> +        mem->bus.is_iomem = true;
>> +        break;
>>       default:
>>           return -EINVAL;
>>       }
>> @@ -1267,6 +1275,7 @@ uint64_t amdgpu_ttm_tt_pde_flags(struct ttm_tt 
>> *ttm, struct ttm_resource *mem)
>>           flags |= AMDGPU_PTE_VALID;
>>         if (mem && (mem->mem_type == TTM_PL_TT ||
>> +            mem->mem_type == AMDGPU_PL_DOORBELL ||
>>               mem->mem_type == AMDGPU_PL_PREEMPT)) {
>>           flags |= AMDGPU_PTE_SYSTEM;
>>   diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> index 967b265dbfa1..9cf5d8419965 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h
>> @@ -33,6 +33,7 @@
>>   #define AMDGPU_PL_GWS        (TTM_PL_PRIV + 1)
>>   #define AMDGPU_PL_OA        (TTM_PL_PRIV + 2)
>>   #define AMDGPU_PL_PREEMPT    (TTM_PL_PRIV + 3)
>> +#define AMDGPU_PL_DOORBELL    (TTM_PL_PRIV + 4)
>>     #define AMDGPU_GTT_MAX_TRANSFER_SIZE    512
>>   #define AMDGPU_GTT_NUM_TRANSFER_WINDOWS    2
>