[PATCH 7/7] drm/amdgpu: retry init if it fails due to exclusive mode timeout (v2)

[Ding, Pixel]

Host rejects frequent exclusive mode requesting, otherwise an attacking VF may cause problems. Sleep for a while to let host accept next request here.

— 
Sincerely Yours,
Pixel







On 26/10/2017, 6:44 AM, "Alex Deucher" <alexdeucher at gmail.com> wrote:

>On Tue, Oct 24, 2017 at 10:19 PM, Pixel Ding <Pixel.Ding at amd.com> wrote:
>> From: pding <Pixel.Ding at amd.com>
>>
>> The exclusive mode has real-time limitation in reality, such like being
>> done in 300ms. It's easy observed if running many VF/VMs in single host
>> with heavy CPU workload.
>>
>> If we find the init fails due to exclusive mode timeout, try it again.
>>
>> v2:
>>  - rewrite the condition for readable value.
>>
>> Signed-off-by: pding <Pixel.Ding at amd.com>
>> ---
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 10 ++++++++++
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c    | 14 ++++++++++++--
>>  2 files changed, 22 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> index 2fdd73b..14fe2bc 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> @@ -2301,6 +2301,15 @@ int amdgpu_device_init(struct amdgpu_device *adev,
>>
>>         r = amdgpu_init(adev);
>>         if (r) {
>> +               /* failed in exclusive mode due to timeout */
>> +               if (amdgpu_sriov_vf(adev) &&
>> +                   !amdgpu_sriov_runtime(adev) &&
>> +                   amdgpu_virt_mmio_blocked(adev) &&
>> +                   !amdgpu_virt_wait_reset(adev)) {
>> +                       dev_err(adev->dev, "VF exclusive mode timeout\n");
>> +                       r = -EAGAIN;
>> +                       goto failed;
>> +               }
>>                 dev_err(adev->dev, "amdgpu_init failed\n");
>>                 amdgpu_vf_error_put(adev, AMDGIM_ERROR_VF_AMDGPU_INIT_FAIL, 0, 0);
>>                 amdgpu_fini(adev);
>> @@ -2388,6 +2397,7 @@ int amdgpu_device_init(struct amdgpu_device *adev,
>>         amdgpu_vf_error_trans_all(adev);
>>         if (runtime)
>>                 vga_switcheroo_fini_domain_pm_ops(adev->dev);
>> +
>>         return r;
>>  }
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
>> index 4a9f749..f4ee407 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
>> @@ -86,7 +86,7 @@ void amdgpu_driver_unload_kms(struct drm_device *dev)
>>  int amdgpu_driver_load_kms(struct drm_device *dev, unsigned long flags)
>>  {
>>         struct amdgpu_device *adev;
>> -       int r, acpi_status;
>> +       int r, acpi_status, retry = 0;
>>
>>  #ifdef CONFIG_DRM_AMDGPU_SI
>>         if (!amdgpu_si_support) {
>> @@ -122,6 +122,7 @@ int amdgpu_driver_load_kms(struct drm_device *dev, unsigned long flags)
>>                 }
>>         }
>>  #endif
>> +retry_init:
>>
>>         adev = kzalloc(sizeof(struct amdgpu_device), GFP_KERNEL);
>>         if (adev == NULL) {
>> @@ -144,7 +145,16 @@ int amdgpu_driver_load_kms(struct drm_device *dev, unsigned long flags)
>>          * VRAM allocation
>>          */
>>         r = amdgpu_device_init(adev, dev, dev->pdev, flags);
>> -       if (r) {
>> +       if (++retry >= 3 && r == -EAGAIN) {
>
>Might be better to check for -EAGAIN first.
>
>> +               adev->virt.caps &= ~AMDGPU_SRIOV_CAPS_RUNTIME;
>> +               adev->virt.ops = NULL;
>> +               amdgpu_device_fini(adev);
>> +               kfree(adev);
>> +               dev->dev_private = NULL;
>> +               msleep(5000);
>
>
>Why do we need the sleep here?
>
>> +               dev_err(&dev->pdev->dev, "retry init %d\n", retry);
>> +               goto retry_init;
>> +       } else if (r) {
>>                 dev_err(&dev->pdev->dev, "Fatal error during GPU init\n");
>>                 goto out;
>>         }
>> --
>> 2.9.5
>>
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