Ah, in this case please separate the amdgpu_vm_bo_rmv() from setting csa_addr to NULL.

Cause amdgpu_vm_bo_rmv() should come before amdgpu_vm_fini() and that in turn should become before waiting for the scheduler so that the MM knows that the memory is about to be freed.


Regards,
Christian.

Am 13.01.2017 um 10:56 schrieb Liu, Monk:

only with amdgpu_vm_bo_rmv() won't has such bug, but in another branch for sriov, we not only call vm_bo_rmv(), and we also set csa_addr to NULL after it, so the NULL address is inserted in RB, and when preemption occured, CP backup snapshot to NULL address.


although in staging-4.9 we didn't set csa_addr to NULL (because as you suggested we always use HARDCODE/MACRO for CSA address), but logically we'd better put CSA unmapping stuffs behind "sched_entity_fini", which is more reasonable ...


BR Monk

------------------------------------------------------------------------
*发件人:* amd-gfx <amd-gfx-boun...@lists.freedesktop.org> 代表 Christian König <deathsim...@vodafone.de>
*发送时间:* 2017年1月13日 17:25:09
*收件人:* Liu, Monk; amd-gfx@lists.freedesktop.org
*主题:* Re: [PATCH] drm/amdgpu:put CSA unmap after sched_entity_fini
Am 13.01.2017 um 05:11 schrieb Monk Liu:
> otherwise CSA may unmapped before gpu_scheduler scheduling
> jobs and trigger VM fault on CSA address
>
> Change-Id: Ib2e25ededf89bca44c764477dd2f9127024ca78c
> Signed-off-by: Monk Liu <monk....@amd.com>

Did you really run into an issue because of that?

Calling amdgpu_vm_bo_rmv() shouldn't affect the page tables nor already
submitted command submissions in any way.

Regards,
Christian.

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c | 8 --------
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c  | 8 ++++++++
>   2 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
> index 45484c0..e13cdde 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
> @@ -694,14 +694,6 @@ void amdgpu_driver_postclose_kms(struct drm_device *dev,
>        amdgpu_uvd_free_handles(adev, file_priv);
>        amdgpu_vce_free_handles(adev, file_priv);
>
> -     if (amdgpu_sriov_vf(adev)) {
> -             /* TODO: how to handle reserve failure */
> - BUG_ON(amdgpu_bo_reserve(adev->virt.csa_obj, false));
> -             amdgpu_vm_bo_rmv(adev, fpriv->vm.csa_bo_va);
> -             fpriv->vm.csa_bo_va = NULL;
> - amdgpu_bo_unreserve(adev->virt.csa_obj);
> -     }
> -
>        amdgpu_vm_fini(adev, &fpriv->vm);
>
> idr_for_each_entry(&fpriv->bo_list_handles, list, handle)
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index d05546e..94098bc 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1608,6 +1608,14 @@ void amdgpu_vm_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
>
>        amd_sched_entity_fini(vm->entity.sched, &vm->entity);
>
> +     if (amdgpu_sriov_vf(adev)) {
> +             /* TODO: how to handle reserve failure */
> + BUG_ON(amdgpu_bo_reserve(adev->virt.csa_obj, false));
> +             amdgpu_vm_bo_rmv(adev, vm->csa_bo_va);
> +             vm->csa_bo_va = NULL;
> + amdgpu_bo_unreserve(adev->virt.csa_obj);
> +     }
> +
>        if (!RB_EMPTY_ROOT(&vm->va)) {
>                dev_err(adev->dev, "still active bo inside vm\n");
>        }


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