[PATCH 3/3] drm/amdgpu: fix gpu reset issue

[zhoucm1]

Hi Christian,

We possibly must re-consider this patch, the direct issue is VM FAULT 
after gpu reset. one obvious bug is we could bind gtt to gart during GPU 
reset, binding gtt to gart needs to fill gart table and tlb flush, which 
is parallel with gpu reset thread.

Regards,
David Zhou

On 2017年04月21日 16:27, Christian König wrote:
> NAK, that is exactly what we wanted to avoid.
>
> We used to have an exclusive lock for this and it cause a whole bunch 
> of problems.
>
> Please elaborate why that should be necessary.
>
> Regards,
> Christian.
>
> Am 21.04.2017 um 09:08 schrieb Roger.He:
>> Change-Id: Ib77d33a09f348ebf2e3a9d7861411f4b951ebf7c
>> Signed-off-by: Roger.He <Hongbo.He at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu.h        |  6 ++++++
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 16 +++++++++++++++-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c    |  4 ++++
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ioc32.c  |  7 ++++++-
>>   4 files changed, 31 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> index 71364f5..ab0ffa8 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> @@ -1526,6 +1526,7 @@ struct amdgpu_device {
>>       atomic64_t            num_bytes_moved;
>>       atomic64_t            num_evictions;
>>       atomic_t            gpu_reset_counter;
>> +    atomic_t            gpu_reset_state;
>>         /* data for buffer migration throttling */
>>       struct {
>> @@ -1851,6 +1852,11 @@ amdgpu_get_sdma_instance(struct amdgpu_ring 
>> *ring)
>>   #define amdgpu_psp_check_fw_loading_status(adev, i) 
>> (adev)->firmware.funcs->check_fw_loading_status((adev), (i))
>>     /* Common functions */
>> +static inline int amdgpu_device_is_reset(struct amdgpu_device *adev)
>> +{
>> +    return atomic_read(&adev->gpu_reset_state);
>> +}
>> +
>>   int amdgpu_gpu_reset(struct amdgpu_device *adev);
>>   bool amdgpu_need_backup(struct amdgpu_device *adev);
>>   void amdgpu_pci_config_reset(struct amdgpu_device *adev);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> index f882496..0fb4716 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> @@ -1894,6 +1894,7 @@ int amdgpu_device_init(struct amdgpu_device *adev,
>>       mutex_init(&adev->grbm_idx_mutex);
>>       mutex_init(&adev->mn_lock);
>>       hash_init(adev->mn_hash);
>> +    atomic_set(&adev->gpu_reset_state, 0);
>>         amdgpu_check_arguments(adev);
>>   @@ -2655,6 +2656,18 @@ int amdgpu_sriov_gpu_reset(struct 
>> amdgpu_device *adev, bool voluntary)
>>   }
>>     /**
>> + * amdgpu_device_set_reset_state - set gpu reset state
>> + *
>> + * @adev: amdgpu device pointer
>> + * @state: true when start to reset gpu; false: reset done
>> + */
>> +static inline void amdgpu_device_set_reset_state(struct 
>> amdgpu_device *adev,
>> +                            bool state)
>> +{
>> +    atomic_set(&adev->gpu_reset_state, state);
>> +}
>> +
>> +/**
>>    * amdgpu_gpu_reset - reset the asic
>>    *
>>    * @adev: amdgpu device pointer
>> @@ -2678,7 +2691,7 @@ int amdgpu_gpu_reset(struct amdgpu_device *adev)
>>       }
>>         atomic_inc(&adev->gpu_reset_counter);
>> -
>> +    amdgpu_device_set_reset_state(adev, true);
>>       /* block TTM */
>>       resched = ttm_bo_lock_delayed_workqueue(&adev->mman.bdev);
>>       /* store modesetting */
>> @@ -2811,6 +2824,7 @@ int amdgpu_gpu_reset(struct amdgpu_device *adev)
>>           dev_info(adev->dev, "GPU reset failed\n");
>>       }
>>   +    amdgpu_device_set_reset_state(adev, false);
>>       return r;
>>   }
>>   diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>> index ead00d7..8cc14af 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>> @@ -679,11 +679,15 @@ long amdgpu_drm_ioctl(struct file *filp,
>>       struct drm_file *file_priv = filp->private_data;
>>       struct drm_device *dev;
>>       long ret;
>> +
>>       dev = file_priv->minor->dev;
>>       ret = pm_runtime_get_sync(dev->dev);
>>       if (ret < 0)
>>           return ret;
>>   +    while (amdgpu_device_is_reset(dev->dev_private))
>> +        msleep(100);
>> +
>>       ret = drm_ioctl(filp, cmd, arg);
>>         pm_runtime_mark_last_busy(dev->dev);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ioc32.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ioc32.c
>> index 2648291..22b8059 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ioc32.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ioc32.c
>> @@ -36,10 +36,15 @@
>>   long amdgpu_kms_compat_ioctl(struct file *filp, unsigned int cmd, 
>> unsigned long arg)
>>   {
>>       unsigned int nr = DRM_IOCTL_NR(cmd);
>> +    struct drm_file *file_priv = filp->private_data;
>> +    struct amdgpu_device *adev = file_priv->minor->dev->dev_private;
>>       int ret;
>>   -    if (nr < DRM_COMMAND_BASE)
>> +    if (nr < DRM_COMMAND_BASE) {
>> +        while (amdgpu_device_is_reset(adev))
>> +            msleep(100);
>>           return drm_compat_ioctl(filp, cmd, arg);
>> +    }
>>         ret = amdgpu_drm_ioctl(filp, cmd, arg);
>
>