[RFC PATCH 1/2] drm/amdgpu: amdgpu_vram_mgr_new(): Clamp lpfn to total vram

[Alex Deucher]

+ Christian

On Tue, Apr 29, 2025 at 7:24 AM John Olender <john.olender at gmail.com> wrote:
>
> The drm_mm allocator tolerated being passed end > mm->size, but the
> drm_buddy allocator does not.
>
> Restore the pre-buddy-allocator behavior of allowing such placements.
>
> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3448
> Signed-off-by: John Olender <john.olender at gmail.com>

This looks correct to me.
Reviewed-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> index 2d7f82e98df9..abdc52b0895a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> @@ -463,7 +463,7 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
>         int r;
>
>         lpfn = (u64)place->lpfn << PAGE_SHIFT;
> -       if (!lpfn)
> +       if (!lpfn || lpfn > man->size)
>                 lpfn = man->size;
>
>         fpfn = (u64)place->fpfn << PAGE_SHIFT;
> --
> 2.47.2
>