Re: [Intel-gfx] [PATCH v2] drm/i915/huc: Fix error reported by I915_PARAM_HUC_STATUS

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 25.02.2020 08:49, Ye, Tony wrote:
> 
> 
> On 2/21/2020 11:32 PM, Michal Wajdeczko wrote:
>>  From commit 84b1ca2f0e68 ("drm/i915/uc: prefer intel_gt over i915
>> in GuC/HuC paths") we stopped using HUC_STATUS error -ENODEV only
>> to indicate lack of HuC hardware and we started to use this error
>> also for all other cases when HuC was not in use or supported.
>>
>> Fix that by relying again on HAS_GT_UC macro, since currently
>> used function intel_huc_is_supported() is based on HuC firmware
>> support which could be unsupported also due to force disabled
>> GuC firmware.
>>
>> v2: use 0 only for disabled, add more error codes for other failures
>>
>> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
>> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
>> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
>> Cc: Tony Ye <tony.ye@intel.com>
>> Cc: Robert M. Fosha <robert.m.fosha@intel.com>
>> Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> #v1
>> ---
>>   drivers/gpu/drm/i915/gt/uc/intel_huc.c | 29 +++++++++++++++++++++-----
>>   1 file changed, 24 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc.c
>> b/drivers/gpu/drm/i915/gt/uc/intel_huc.c
>> index a74b65694512..301bb5d5e59a 100644
>> --- a/drivers/gpu/drm/i915/gt/uc/intel_huc.c
>> +++ b/drivers/gpu/drm/i915/gt/uc/intel_huc.c
>> @@ -200,9 +200,13 @@ int intel_huc_auth(struct intel_huc *huc)
>>    * This function reads status register to verify if HuC
>>    * firmware was successfully loaded.
>>    *
>> - * Returns: 1 if HuC firmware is loaded and verified,
>> - * 0 if HuC firmware is not loaded and -ENODEV if HuC
>> - * is not present on this platform.
>> + * Returns:
>> + *  * 1 if HuC firmware is loaded and verified,
>> + *  * 0 if HuC firmware was disabled,
>> + *  * -ENODEV if HuC is not present on this platform,
>> + *  * -ENOPKG if HuC firmware was not installed,
>> + *  * -ENOEXEC if HuC firmware is invalid,
>> + *  * -EACCES if HuC firmware was not authenticated.
>>    */
>>   int intel_huc_check_status(struct intel_huc *huc)
>>   {
>> @@ -210,11 +214,26 @@ int intel_huc_check_status(struct intel_huc *huc)
>>       intel_wakeref_t wakeref;
>>       u32 status = 0;
>>   -    if (!intel_huc_is_supported(huc))
>> +    if (!HAS_GT_UC(gt->i915))
>>           return -ENODEV;
>>   +    switch (__intel_uc_fw_status(&huc->fw)) {
>> +    case INTEL_UC_FIRMWARE_NOT_SUPPORTED:
>> +    case INTEL_UC_FIRMWARE_DISABLED:
>> +        return 0;
>> +    case INTEL_UC_FIRMWARE_MISSING:
>> +        return -ENOPKG;
>> +    case INTEL_UC_FIRMWARE_ERROR:
>> +        return -ENOEXEC;
> 
> What about INTEL_UC_FIRMWARE_FAIL?

I assumed that we don't need to handle that case here, since we are
still checking HuC status register below.

But if you want we can improve:
1) return early if FAIL, then check register anyway
2) return early if FAIL, trust fw state and return 1 without checking
register (as same register was already checked when we mark fw state as
RUNNING)

> 
> Regards,
> Tony
> 
>> +    default:
>> +        break;
>> +    }
>> +
>>       with_intel_runtime_pm(gt->uncore->rpm, wakeref)
>>           status = intel_uncore_read(gt->uncore, huc->status.reg);
>>   -    return (status & huc->status.mask) == huc->status.value;
>> +    if ((status & huc->status.mask) != huc->status.value)
>> +        return -EACCES;
>> +
>> +    return 1;
>>   }
>>
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