[PATCH] drm/amdgpu: Fix CSA buffer alloc failed on Vega

[Christian König]

Am 12.11.18 um 11:33 schrieb Rex Zhu:
> Alloc_pte failed when the VA address located in
> the higher arrange of 256T.
>
> so reserve the csa buffer under 128T as a work around.
>
> [  122.979425] amdgpu 0000:03:00.0: va above limit (0xFFFFFFFFFFF1F >= 0x1000000000)
> [  122.987080] BUG: unable to handle kernel paging request at ffff880e1a79fff8
>
> Signed-off-by: Rex Zhu <Rex.Zhu at amd.com>

Well NAK, userspace wants to use the full address space below 128T for SVM.

The problem is rather that you incorrectly use amdgpu_csa_vaddr(). See 
the code in amdgpu_driver_open_kms() how to do it correctly:

>                 uint64_t csa_addr = amdgpu_csa_vaddr(adev) & 
> AMDGPU_GMC_HOLE_MASK;
>
>                 r = amdgpu_map_static_csa(adev, &fpriv->vm, 
> adev->virt.csa_obj,
> &fpriv->csa_va, csa_addr, AMDGPU_CSA_SIZE);
>                 if (r)
>                         goto error_vm;

Christian.


> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c | 4 ++--
>   drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 2 +-
>   2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c
> index fea4555..e2f325b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_csa.c
> @@ -36,9 +36,9 @@ uint64_t amdgpu_csa_vaddr(struct amdgpu_device *adev, uint32_t id)
>   {
>   	uint64_t addr = adev->vm_manager.max_pfn << AMDGPU_GPU_PAGE_SHIFT;
>   
> -	addr -= AMDGPU_VA_RESERVED_SIZE * id;
> +	addr = min(addr, AMDGPU_GMC_HOLE_START);
>   
> -	addr = amdgpu_gmc_sign_extend(addr);
> +	addr -= (uint64_t)AMDGPU_VA_RESERVED_SIZE * id;
>   
>   	return addr;
>   }
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
> index 338a091..ea6a12a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
> @@ -711,7 +711,7 @@ static int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file
>   
>   		dev_info.virtual_address_offset = AMDGPU_VA_RESERVED_SIZE;
>   		dev_info.virtual_address_max =
> -			min(vm_size, AMDGPU_GMC_HOLE_START);
> +			min(vm_size, AMDGPU_GMC_HOLE_START - adev->vm_manager.reserved_vm_size);
>   
>   		if (vm_size > AMDGPU_GMC_HOLE_START) {
>   			dev_info.high_va_offset = AMDGPU_GMC_HOLE_END;