On 11/6/26 08:25, Jesse Zhang wrote:
> amdgpu_cwsr_alloc() creates the TMA BO of every opened render node with
> the resv of the VM root PD and as ttm_bo_type_kernel. The VM puts kernel
> BOs which share its resv on its page table lists, so the TMA BO is
> treated as a page table: after a VRAM losing reset its bo_va moves to
> the page tables needing an update, and amdgpu_vm_update_pdes() tries to
> write its PDE. It has no parent page directory, so that fails, and fails
> again on every following submission of the file.
>
> On navi31, submitting on a render node, then amdgpu_gpu_recover and
> submitting again, also with a new context:
>
> amdgpu 0000:03:00.0: VRAM is lost due to GPU reset!
> amdgpu 0000:03:00.0: GPU reset(1) succeeded!
> WARNING: amdgpu_vm_pt.c:664 at amdgpu_vm_pde_update+0x329/0x5d0 [amdgpu],
> CPU#3: vmreinit/2728
>
> and every command submission fails with -EINVAL from then on.
>
> Create the TMA BO as a device BO, a per VM BO like the other ones.
> With that the submissions after the reset complete.
>
> Fixes: 8a93aae9896b ("drm/amdgpu: Add CWSR infrastructure for user queues")
> Signed-off-by: Jesse Zhang <[email protected]>
Clear NAK, that allows to mmap the CWSR BO from userspace and that in turn is
seen as highly problematic.
IIRC Sunil already stumbled over this issue as well and we agreed to not check
for ttm_bo_type_kernel any more.
Could be that Sunil and I didn't fix all problems with this, maybe take a look
at the history of amdgpu_vm.c.
Regards,
Christian.
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_cwsr.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cwsr.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_cwsr.c
> index daca0a1ac990..52ae77a08ca0 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cwsr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cwsr.c
> @@ -433,7 +433,11 @@ int amdgpu_cwsr_alloc(struct amdgpu_device *adev, struct
> amdgpu_vm *vm,
> bp.domain = AMDGPU_GEM_DOMAIN_GTT;
> bp.flags = AMDGPU_GEM_CREATE_CPU_GTT_USWC |
> AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
> - bp.type = ttm_bo_type_kernel;
> + /*
> + * Not ttm_bo_type_kernel: the VM takes kernel BOs sharing its resv
> + * for page tables.
> + */
> + bp.type = ttm_bo_type_device;
> bp.bo_ptr_size = sizeof(struct amdgpu_bo);
> bp.resv = vm->root.bo->tbo.base.resv;
>
