SRIOV need to reserve a memory at an offset that set by GIM/hypervisor side, 
but I'm not sure how to do it perfectly,  currently we call bo_create to 
allocate a VRAM BO, and call pin_restrict with "offset" as parameter for "min" 
and "offset + size" as "max",


I feel strange of above approach frankly speaking (unless the new offset equals 
to the original offset from bo_create),


Because the original gpu offset (from the bo_create) is different with the new 
"offset" provided by GIM, what will TTM/DRM do on the range of <original 
offset, new offset> after we pin the bo to <new offset, new offset+ size> ???


BR Monk


________________________________
From: amd-gfx <[email protected]> on behalf of Deucher, 
Alexander <[email protected]>
Sent: Tuesday, September 12, 2017 11:59:35 PM
To: 'Christian König'; [email protected]
Subject: RE: [PATCH 4/5] drm/amdgpu: cleanup amdgpu_bo_pin_restricted

> -----Original Message-----
> From: amd-gfx [mailto:[email protected]] On Behalf
> Of Christian König
> Sent: Tuesday, September 12, 2017 5:09 AM
> To: [email protected]
> Subject: [PATCH 4/5] drm/amdgpu: cleanup amdgpu_bo_pin_restricted
>
> From: Christian König <[email protected]>
>
> Nobody is using the min/max interface any more.
>
> Signed-off-by: Christian König <[email protected]>

I'm not sure it's a good idea to get rid of this.  I can see a need to reserve 
memory at specific offsets in memory.  Specifically I think SR-IOV will be 
placing structures in memory to communicate configuration details from the host 
to the guest.  Also, we should be reserving the vbios scratch area, but we 
don't currently.

Alex

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 39 +++++------------------
> -------
>  drivers/gpu/drm/amd/amdgpu/amdgpu_object.h |  3 ---
>  2 files changed, 6 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> index 726a662..8a8add3 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> @@ -629,20 +629,15 @@ void amdgpu_bo_unref(struct amdgpu_bo **bo)
>                *bo = NULL;
>  }
>
> -int amdgpu_bo_pin_restricted(struct amdgpu_bo *bo, u32 domain,
> -                          u64 min_offset, u64 max_offset,
> -                          u64 *gpu_addr)
> +int amdgpu_bo_pin(struct amdgpu_bo *bo, u32 domain, u64 *gpu_addr)
>  {
>        struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> +     unsigned lpfn;
>        int r, i;
> -     unsigned fpfn, lpfn;
>
>        if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm))
>                return -EPERM;
>
> -     if (WARN_ON_ONCE(min_offset > max_offset))
> -             return -EINVAL;
> -
>        /* A shared bo cannot be migrated to VRAM */
>        if (bo->prime_shared_count && (domain ==
> AMDGPU_GEM_DOMAIN_VRAM))
>                return -EINVAL;
> @@ -657,12 +652,6 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo
> *bo, u32 domain,
>                if (gpu_addr)
>                        *gpu_addr = amdgpu_bo_gpu_offset(bo);
>
> -             if (max_offset != 0) {
> -                     u64 domain_start = bo->tbo.bdev-
> >man[mem_type].gpu_offset;
> -                     WARN_ON_ONCE(max_offset <
> -                                  (amdgpu_bo_gpu_offset(bo) -
> domain_start));
> -             }
> -
>                return 0;
>        }
>
> @@ -671,23 +660,12 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo
> *bo, u32 domain,
>        for (i = 0; i < bo->placement.num_placement; i++) {
>                /* force to pin into visible video ram */
>                if ((bo->placements[i].flags & TTM_PL_FLAG_VRAM) &&
> -                 !(bo->flags & AMDGPU_GEM_CREATE_NO_CPU_ACCESS)
> &&
> -                 (!max_offset || max_offset >
> -                  adev->mc.visible_vram_size)) {
> -                     if (WARN_ON_ONCE(min_offset >
> -                                      adev->mc.visible_vram_size))
> -                             return -EINVAL;
> -                     fpfn = min_offset >> PAGE_SHIFT;
> +                 !(bo->flags & AMDGPU_GEM_CREATE_NO_CPU_ACCESS))
> {
>                        lpfn = adev->mc.visible_vram_size >> PAGE_SHIFT;
> -             } else {
> -                     fpfn = min_offset >> PAGE_SHIFT;
> -                     lpfn = max_offset >> PAGE_SHIFT;
> +                     if (!bo->placements[i].lpfn ||
> +                         (lpfn && lpfn < bo->placements[i].lpfn))
> +                             bo->placements[i].lpfn = lpfn;
>                }
> -             if (fpfn > bo->placements[i].fpfn)
> -                     bo->placements[i].fpfn = fpfn;
> -             if (!bo->placements[i].lpfn ||
> -                 (lpfn && lpfn < bo->placements[i].lpfn))
> -                     bo->placements[i].lpfn = lpfn;
>                bo->placements[i].flags |= TTM_PL_FLAG_NO_EVICT;
>        }
>
> @@ -718,11 +696,6 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo
> *bo, u32 domain,
>        return r;
>  }
>
> -int amdgpu_bo_pin(struct amdgpu_bo *bo, u32 domain, u64 *gpu_addr)
> -{
> -     return amdgpu_bo_pin_restricted(bo, domain, 0, 0, gpu_addr);
> -}
> -
>  int amdgpu_bo_unpin(struct amdgpu_bo *bo)
>  {
>        struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> index 39b6bf6..4b2c042 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.h
> @@ -211,9 +211,6 @@ void amdgpu_bo_kunmap(struct amdgpu_bo *bo);
>  struct amdgpu_bo *amdgpu_bo_ref(struct amdgpu_bo *bo);
>  void amdgpu_bo_unref(struct amdgpu_bo **bo);
>  int amdgpu_bo_pin(struct amdgpu_bo *bo, u32 domain, u64 *gpu_addr);
> -int amdgpu_bo_pin_restricted(struct amdgpu_bo *bo, u32 domain,
> -                          u64 min_offset, u64 max_offset,
> -                          u64 *gpu_addr);
>  int amdgpu_bo_unpin(struct amdgpu_bo *bo);
>  int amdgpu_bo_evict_vram(struct amdgpu_device *adev);
>  int amdgpu_bo_init(struct amdgpu_device *adev);
> --
> 2.7.4
>
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> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
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