[PATCH] drm/amdgpu: Enable XGMI mapping for peer device

[Christian König]

Am 25.02.19 um 19:47 schrieb Liu, Shaoyun:
> On 2019-02-25 10:50 a.m., Christian König wrote:
>> Am 22.02.19 um 22:28 schrieb Liu, Shaoyun:
>>> Adjust vram base offset for XGMI mapping when update the PT entry so
>>> the address will fall into correct XGMI aperture for peer device
>>>
>>> Change-Id: I78bdf244da699d2559481ef5afe9663b3e752236
>>> Signed-off-by: shaoyunl <shaoyun.liu at amd.com>
>>> ---
>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 35
>>> +++++++++++++++++++++++++++++-----
>>>    1 file changed, 30 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>> index 942b5eb..e41563b 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>> @@ -1890,6 +1890,7 @@ static int amdgpu_vm_bo_split_mapping(struct
>>> amdgpu_device *adev,
>>>                          dma_addr_t *pages_addr,
>>>                          struct amdgpu_vm *vm,
>>>                          struct amdgpu_bo_va_mapping *mapping,
>>> +                      uint64_t vram_base_offset,
>> NAK, please just make sure that the correct adev is used down below.
> [shaoyun]  The adev not only be  used to get vram_base_offset . It's
> also used to for all other device specific stuff including the PTE , PDE
> address  etc .  What we want is the offset that fall into peer device FB
> to be programmed into local device's PT entry .  I don't see a better
> solution than add the vram_base_offset as a parameter here .

Sounds like you didn't understood me. You should just not add the 
vram_base_offset as the parameter, but the adev to use.

E.g. something like bo_adev, src_adev or mem_adev or something like that.

Christian.

>
>>>                          uint64_t flags,
>>>                          struct drm_mm_node *nodes,
>>>                          struct dma_fence **fence)
>>> @@ -1965,7 +1966,7 @@ static int amdgpu_vm_bo_split_mapping(struct
>>> amdgpu_device *adev,
>>>                }
>>>              } else if (flags & AMDGPU_PTE_VALID) {
>>> -            addr += adev->vm_manager.vram_base_offset;
>>> +            addr += vram_base_offset;
>>>                addr += pfn << PAGE_SHIFT;
>>>            }
>>>    @@ -2012,6 +2013,8 @@ int amdgpu_vm_bo_update(struct amdgpu_device
>>> *adev,
>>>        struct drm_mm_node *nodes;
>>>        struct dma_fence *exclusive, **last_update;
>>>        uint64_t flags;
>>> +    uint64_t vram_base_offset = adev->vm_manager.vram_base_offset;
>>> +    struct amdgpu_device *bo_adev;
>>>        int r;
>>>          if (clear || !bo) {
>>> @@ -2030,9 +2033,31 @@ int amdgpu_vm_bo_update(struct amdgpu_device
>>> *adev,
>>>            exclusive = reservation_object_get_excl(bo->tbo.resv);
>>>        }
>>>    -    if (bo)
>>> +    if (bo) {
>>>            flags = amdgpu_ttm_tt_pte_flags(adev, bo->tbo.ttm, mem);
>>> -    else
>>> +        bo_adev = amdgpu_ttm_adev(bo->tbo.bdev);
>>> +        if (mem && mem->mem_type == TTM_PL_VRAM && adev != bo_adev) {
>>> +            if (drm_debug & DRM_UT_DRIVER) {
>>> +                list_for_each_entry(mapping, &bo_va->invalids, list) {
>>> +                    DRM_DEBUG_DRIVER("Try map VRAM va 0x%llx -
>>> 0x%llx, offset 0x%llx, from dev %s for peer GPU %s access.\n",
>>> +                        mapping->start << PAGE_SHIFT,
>>> +                        ((mapping->last + 1) << PAGE_SHIFT) - 1,
>>> +                        nodes ? nodes->start << PAGE_SHIFT : 0ll,
>>> +                        dev_name(bo_adev->dev),
>>> +                        dev_name(adev->dev));
>> Big NAK as well. If you want to make that kind of debugging the please
>> use trace points for it and not such extensive debug messages.
> [shaoyunl] This debug message can help me debug on some VM fault during
> XGMI bring up . Not sure whether I can get same  if I move it into trace
> since it may lose some sequence information especially when  I need to
> coordinate with KFD (or even  user level) print message for memory
> allocation and mapping .  But anyway , if you strongly against this
> debug message , I can remove it .
>
> Regards
>
> shaoyun.liu
>
>
>> Regards,
>> Christian.
>>
>>> +                }
>>> +            }
>>> +            if (adev->gmc.xgmi.hive_id &&
>>> +                adev->gmc.xgmi.hive_id == bo_adev->gmc.xgmi.hive_id) {
>>> +                vram_base_offset =
>>> bo_adev->vm_manager.vram_base_offset;
>>> +                DRM_DEBUG_DRIVER("Used XGMI mapping,
>>> vram_base_offset 0x%llx.\n",
>>> +                    vram_base_offset);
>>> +            } else {
>>> +                DRM_DEBUG_DRIVER("Failed to map the VRAM for other
>>> device access.\n");
>>> +                return -EINVAL;
>>> +            }
>>> +        }
>>> +    } else
>>>            flags = 0x0;
>>>          if (clear || (bo && bo->tbo.resv == vm->root.base.bo->tbo.resv))
>>> @@ -2050,8 +2075,8 @@ int amdgpu_vm_bo_update(struct amdgpu_device
>>> *adev,
>>>          list_for_each_entry(mapping, &bo_va->invalids, list) {
>>>            r = amdgpu_vm_bo_split_mapping(adev, exclusive, pages_addr,
>>> vm,
>>> -                           mapping, flags, nodes,
>>> -                           last_update);
>>> +                           mapping, vram_base_offset, flags,
>>> +                           nodes, last_update);
>>>            if (r)
>>>                return r;
>>>        }
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