Re: [PATCH] drm/amdkfd: fix the hang caused by the write reorder to fence_addr

[Philip Yang <yangp@xxxxxxx>]

On 2024-10-18 01:31, Zhao, Victor wrote:

> [AMD Official Use Only - AMD Internal Distribution Only]
>
> [AMD Official Use Only - AMD Internal Distribution Only]
>
> Ping. Please help review.
>
> Thanks,
> Victor
>
> -----Original Message-----
> From: Victor Zhao <Victor.Zhao@xxxxxxx>
> Sent: Thursday, October 17, 2024 4:35 PM
> To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: Zhao, Victor <Victor.Zhao@xxxxxxx>
> Subject: [PATCH] drm/amdkfd: fix the hang caused by the write reorder to fence_addr
>
> make sure KFD_FENCE_INIT write to fence_addr before pm_send_query_status called, to avoid qcm fence timeout caused by incorrect ordering.
>
> Signed-off-by: Victor Zhao <Victor.Zhao@xxxxxxx>
>     
    Reviewed-by: Philip Yang <Philip.Yang@xxxxxxx>
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c | 1 +  drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h | 2 +-
>  2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> index b2b16a812e73..d9264a353775 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> @@ -2254,6 +2254,7 @@ static int unmap_queues_cpsch(struct device_queue_manager *dqm,
>                 goto out;
>
>         *dqm->fence_addr = KFD_FENCE_INIT;
> +       mb();
>         pm_send_query_status(&dqm->packet_mgr, dqm->fence_gpu_addr,
>                                 KFD_FENCE_COMPLETED);
>         /* should be timed out */
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
> index 09ab36f8e8c6..bddb169bb301 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
> @@ -260,7 +260,7 @@ struct device_queue_manager {
>         uint16_t                vmid_pasid[VMID_NUM];
>         uint64_t                pipelines_addr;
>         uint64_t                fence_gpu_addr;
> -       uint64_t                *fence_addr;
> +       volatile uint64_t       *fence_addr;
>         struct kfd_mem_obj      *fence_mem;
>         bool                    active_runlist;
>         int                     sched_policy;
> --
> 2.34.1
>
>