[PATCH] drm/amdgpu: exclude domain start when calucales offset for AGP aperture BOs

[Deucher, Alexander]

[Public]

It happens in amdgpu_gmc_agp_addr() which is called from amdgpu_ttm_alloc_gart().

Alex
________________________________
From: Koenig, Christian <Christian.Koenig at amd.com>
Sent: Friday, November 10, 2023 9:14 AM
To: Zhang, Yifan <Yifan1.Zhang at amd.com>; amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>
Cc: Deucher, Alexander <Alexander.Deucher at amd.com>; Zhang, Jesse(Jie) <Jesse.Zhang at amd.com>
Subject: Re: [PATCH] drm/amdgpu: exclude domain start when calucales offset for AGP aperture BOs

Am 10.11.23 um 13:52 schrieb Yifan Zhang:
> For BOs in AGP aperture, tbo.resource->start includes AGP aperture start.


Well big NAK to that. tbo.resource->start should never ever include the
AGP aperture start in the first place.

How did that happen?

Regards,
Christian.

> Don't add it again in amdgpu_bo_gpu_offset. This issue was mitigated due to
> GART aperture start was 0 until this patch ("a013c94d5aca drm/amdgpu/gmc11:
> set gart placement GC11") changes GART start to a non-zero value.
>
> Reported-by: Jesse Zhang <Jesse.Zhang at amd.com>
> Signed-off-by: Yifan Zhang <yifan1.zhang at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c    |  7 +++++++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h    |  1 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 10 ++++++++--
>   3 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> index 5f71414190e9..00e940eb69ab 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c
> @@ -169,6 +169,13 @@ int amdgpu_gmc_set_pte_pde(struct amdgpu_device *adev, void *cpu_pt_addr,
>        return 0;
>   }
>
> +bool bo_in_agp_aperture(struct amdgpu_bo *bo)
> +{
> +     struct ttm_buffer_object *tbo = &(bo->tbo);
> +     struct amdgpu_device *adev = amdgpu_ttm_adev(tbo->bdev);
> +
> +     return (tbo->resource->start << PAGE_SHIFT) > adev->gmc.agp_start;
> +}
>   /**
>    * amdgpu_gmc_agp_addr - return the address in the AGP address space
>    *
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
> index e699d1ca8deb..448dc08e83de 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
> @@ -393,6 +393,7 @@ int amdgpu_gmc_set_pte_pde(struct amdgpu_device *adev, void *cpu_pt_addr,
>                                uint64_t flags);
>   uint64_t amdgpu_gmc_pd_addr(struct amdgpu_bo *bo);
>   uint64_t amdgpu_gmc_agp_addr(struct ttm_buffer_object *bo);
> +bool bo_in_agp_aperture(struct amdgpu_bo *bo);
>   void amdgpu_gmc_sysvm_location(struct amdgpu_device *adev, struct amdgpu_gmc *mc);
>   void amdgpu_gmc_vram_location(struct amdgpu_device *adev, struct amdgpu_gmc *mc,
>                              u64 base);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> index cef920a93924..91a011d63ab4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> @@ -39,6 +39,7 @@
>   #include "amdgpu.h"
>   #include "amdgpu_trace.h"
>   #include "amdgpu_amdkfd.h"
> +#include "amdgpu_gmc.h"
>
>   /**
>    * DOC: amdgpu_object
> @@ -1529,8 +1530,13 @@ u64 amdgpu_bo_gpu_offset_no_check(struct amdgpu_bo *bo)
>        struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>        uint64_t offset;
>
> -     offset = (bo->tbo.resource->start << PAGE_SHIFT) +
> -              amdgpu_ttm_domain_start(adev, bo->tbo.resource->mem_type);
> +     /* tbo.resource->start includes agp_start for AGP BOs */
> +     if (bo_in_agp_aperture(bo)) {
> +             offset = (bo->tbo.resource->start << PAGE_SHIFT);
> +     } else {
> +             offset = (bo->tbo.resource->start << PAGE_SHIFT) +
> +                      amdgpu_ttm_domain_start(adev, bo->tbo.resource->mem_type);
> +     }
>
>        return amdgpu_gmc_sign_extend(offset);
>   }

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