[PATCH 2/2] drm/amd/amdgpu: force flush resubmit job

[Chen, JingWen]

[AMD Official Use Only - Internal Distribution Only]

Consider this sequence:
1. GPU reset begin
2. device reset count + 1
3. job id 1 scheduled with vm_need_flush=false
4. When handling this job in vm_flush, amdgpu_vmid_had_gpu_reset will return true, thus this job will be flush and the vmid_reset_count will be set equals to device_reset_count
5. stop drm scheduler
6. GPU do real reset
7. resubmit job id 1 with vm_need_flush=false
8. Job id 1 is the first job to resubmit after reset. This time amdgpu_vmid_had_gpu_reset returns false and the vm_need_flush==false

Then no one will flush pd_addr and vmid for jobs after resubmit. In this sequence amdgpu_vmid_had_gpu_reset doesn't work.


Best Regards,
JingWen Chen

-----Original Message-----
From: Koenig, Christian <Christian.Koenig at amd.com>
Sent: Thursday, February 25, 2021 3:46 PM
To: Chen, JingWen <JingWen.Chen2 at amd.com>; amd-gfx at lists.freedesktop.org
Cc: Liu, Monk <Monk.Liu at amd.com>
Subject: Re: [PATCH 2/2] drm/amd/amdgpu: force flush resubmit job



Am 25.02.21 um 06:27 schrieb Jingwen Chen:
> [Why]
> when a job is scheduled during TDR(after device reset count increase
> and before drm_sched_stop), this job won't do vm_flush when resubmit
> itself after GPU reset done. This can lead to a page fault.
>
> [How]
> Always do vm_flush for resubmit job.

NAK, what do you think amdgpu_vmid_had_gpu_reset already does?

Christian.

>
> Signed-off-by: Jingwen Chen <Jingwen.Chen2 at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index fdbe7d4e8b8b..4af2c5d15950 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1088,7 +1088,8 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job,
>   if (update_spm_vmid_needed && adev->gfx.rlc.funcs->update_spm_vmid)
>   adev->gfx.rlc.funcs->update_spm_vmid(adev, job->vmid);
>
> -if (amdgpu_vmid_had_gpu_reset(adev, id)) {
> +if (amdgpu_vmid_had_gpu_reset(adev, id)||
> +(job->base.flags & DRM_FLAG_RESUBMIT_JOB)) {
>   gds_switch_needed = true;
>   vm_flush_needed = true;
>   pasid_mapping_needed = true;