[PATCH 1/2] drm/amdgpu: Use fw vram offset when allocating stolen vga memory.

[Christian König]

Am 14.03.22 um 19:54 schrieb Yongqiang Sun:
> [Why]
> Memory access violation will happen in case of allocate stolen vga
> memory with size isn't 0.
>
> [How]
> when allocating stolen vga memory, use fw vram offset as the start point
> instead of hard code value 0.

Please stop separating commit message into [Why] and [How], that is not 
well received everywhere.

Apart from that the patch is a certain NAK, you are messing things quite 
up here.

>
> Signed-off-by: Yongqiang Sun <yongqiang.sun at amd.com>
> Change-Id: I7c555a6c1fb4b3fa8685753b4bdcbe215f89ea1e
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 31 +++++++++++++++++++------
>   1 file changed, 24 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 41d6f604813d..1f635fdb0395 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -1708,6 +1708,7 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
>   	uint64_t gtt_size;
>   	int r;
>   	u64 vis_vram_limit;
> +	u64 memory_offset = adev->mman.fw_vram_usage_start_offset + adev->mman.fw_vram_usage_size;
>   
>   	mutex_init(&adev->mman.gtt_window_lock);
>   
> @@ -1774,24 +1775,40 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
>   	 * This is used for VGA emulation and pre-OS scanout buffers to
>   	 * avoid display artifacts while transitioning between pre-OS
>   	 * and driver.  */
> -	r = amdgpu_bo_create_kernel_at(adev, 0, adev->mman.stolen_vga_size,
> +	r = amdgpu_bo_create_kernel_at(adev,
> +					   memory_offset,
> +			           adev->mman.stolen_vga_size,

That is certainly incorrect. See function amdgpu_ttm_fw_reserve_vram_init().

The stolen VGA buffer always started at offset 0 and is independent of 
the range defined by fw_vram_usage_start_offset and fw_vram_usage_size.

Regards,
Christian.

>   				       AMDGPU_GEM_DOMAIN_VRAM,
>   				       &adev->mman.stolen_vga_memory,
>   				       NULL);
>   	if (r)
>   		return r;
> -	r = amdgpu_bo_create_kernel_at(adev, adev->mman.stolen_vga_size,
> +
> +	memory_offset += adev->mman.stolen_vga_size;
> +
> +	r = amdgpu_bo_create_kernel_at(adev,
> +					   memory_offset,
>   				       adev->mman.stolen_extended_size,
>   				       AMDGPU_GEM_DOMAIN_VRAM,
>   				       &adev->mman.stolen_extended_memory,
>   				       NULL);
>   	if (r)
>   		return r;
> -	r = amdgpu_bo_create_kernel_at(adev, adev->mman.stolen_reserved_offset,
> -				       adev->mman.stolen_reserved_size,
> -				       AMDGPU_GEM_DOMAIN_VRAM,
> -				       &adev->mman.stolen_reserved_memory,
> -				       NULL);
> +
> +	memory_offset += adev->mman.stolen_extended_size;
> +
> +	if (adev->mman.stolen_reserved_offset > memory_offset)
> +		r = amdgpu_bo_create_kernel_at(adev, adev->mman.stolen_reserved_offset,
> +						   adev->mman.stolen_reserved_size,
> +						   AMDGPU_GEM_DOMAIN_VRAM,
> +						   &adev->mman.stolen_reserved_memory,
> +						   NULL);
> +	else if (adev->mman.stolen_reserved_offset + adev->mman.stolen_reserved_size > memory_offset)
> +		r = amdgpu_bo_create_kernel_at(adev, memory_offset,
> +						adev->mman.stolen_reserved_offset + adev->mman.stolen_reserved_size - memory_offset,
> +						   AMDGPU_GEM_DOMAIN_VRAM,
> +						   &adev->mman.stolen_reserved_memory,
> +						   NULL);
>   	if (r)
>   		return r;
>