Re: [Intel-gfx] [PATCH 4/7] drm/i915/guc: Record CTB info in error logs

[John Harrison <john.c.harrison@intel.com>]

On 8/2/2022 11:27, Teres Alexis, Alan Previn wrote:
> One minor NIT (though i hope it could be fixed otw in as it adds a bit of ease-of-log-readibility).
> That said, everything else looks good.
>
> Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
>   
> On Wed, 2022-07-27 at 19:20 -0700, John.C.Harrison@Intel.com wrote:
>> From: John Harrison <John.C.Harrison@Intel.com>
>>
>> When debugging GuC communication issues, it is useful to have the CTB
>> info available. So add the state and buffer contents to the error
>> capture log.
>>
>> Also, add a sub-structure for the GuC specific error capture info as
>> it is now becoming numerous.
>>
>> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_gpu_error.c | 59 +++++++++++++++++++++++----
>>   drivers/gpu/drm/i915/i915_gpu_error.h | 20 +++++++--
>>   2 files changed, 67 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
>> index addba75252343..543ba63f958ea 100644
>> --- a/drivers/gpu/drm/i915/i915_gpu_error.c
>> +++ b/drivers/gpu/drm/i915/i915_gpu_error.c
>> @@ -671,6 +671,18 @@ static void err_print_pciid(struct drm_i915_error_state_buf *m,
>>   		   pdev->subsystem_device);
>>   }
>>   
>> +static void err_print_guc_ctb(struct drm_i915_error_state_buf *m,
>> +			      const char *name,
>> +			      const struct intel_ctb_coredump *ctb)
>> +{
>> +	if (!ctb->size)
>> +		return;
>> +
>> +	err_printf(m, "GuC %s CTB: raw: 0x%08X, 0x%08X/%08X, cached: 0x%08X/%08X, desc = 0x%08X, buf = 0x%08X x 0x%08X\n",
>> +		   name, ctb->raw_status, ctb->raw_head, ctb->raw_tail,
>> +		   ctb->head, ctb->tail, ctb->desc_offset, ctb->cmds_offset, ctb->size);
>>
> NIT: to make it more readible on first glance, would be nice to add more descriptive text like "raw: Sts:0x%08X,
> Hd:0x%08X,Tl:0x@08X..." also, the not sure why cmds_offset is presented with a "x size" as opposed to just "desc-off =
> foo1, cmd-off = foo2, size = foo3"?
The line is long enough as it is. I'd rather not make it even longer. 
Same for '<name>: <address> x <size>' rather than '<name> _addr = 
<address>, <name>_size = <size>'. It's useful for readability to keep a 
single CTB channel on a single line but not if that line is excessively 
long.

John.

>> +}
>> +
>>   static void err_print_uc(struct drm_i915_error_state_buf *m,
>>   			 const struct intel_uc_coredump *error_uc)
>>   {
>> @@ -678,8 +690,12 @@ static void err_print_uc(struct drm_i915_error_state_buf *m,
>>   
>>   	intel_uc_fw_dump(&error_uc->guc_fw, &p);
>>   	intel_uc_fw_dump(&error_uc->huc_fw, &p);
>> -	err_printf(m, "GuC timestamp: 0x%08x\n", error_uc->timestamp);
>> -	intel_gpu_error_print_vma(m, NULL, error_uc->guc_log);
>> +	err_printf(m, "GuC timestamp: 0x%08x\n", error_uc->guc.timestamp);
>> +	intel_gpu_error_print_vma(m, NULL, error_uc->guc.vma_log);
>> +	err_printf(m, "GuC CTB fence: %d\n", error_uc->guc.last_fence);
>> +	err_print_guc_ctb(m, "Send", error_uc->guc.ctb + 0);
>> +	err_print_guc_ctb(m, "Recv", error_uc->guc.ctb + 1);
>> +	intel_gpu_error_print_vma(m, NULL, error_uc->guc.vma_ctb);
>>   }
>>   
>>   static void err_free_sgl(struct scatterlist *sgl)
>> @@ -854,7 +870,7 @@ static void __err_print_to_sgl(struct drm_i915_error_state_buf *m,
>>   	if (error->gt) {
>>   		bool print_guc_capture = false;
>>   
>> -		if (error->gt->uc && error->gt->uc->is_guc_capture)
>> +		if (error->gt->uc && error->gt->uc->guc.is_guc_capture)
>>   			print_guc_capture = true;
>>   
>>   		err_print_gt_display(m, error->gt);
>> @@ -1009,7 +1025,8 @@ static void cleanup_uc(struct intel_uc_coredump *uc)
>>   {
>>   	kfree(uc->guc_fw.path);
>>   	kfree(uc->huc_fw.path);
>> -	i915_vma_coredump_free(uc->guc_log);
>> +	i915_vma_coredump_free(uc->guc.vma_log);
>> +	i915_vma_coredump_free(uc->guc.vma_ctb);
>>   
>>   	kfree(uc);
>>   }
>> @@ -1658,6 +1675,23 @@ gt_record_engines(struct intel_gt_coredump *gt,
>>   	}
>>   }
>>   
>> +static void gt_record_guc_ctb(struct intel_ctb_coredump *saved,
>> +			      const struct intel_guc_ct_buffer *ctb,
>> +			      const void *blob_ptr, struct intel_guc *guc)
>> +{
>> +	if (!ctb || !ctb->desc)
>> +		return;
>> +
>> +	saved->raw_status = ctb->desc->status;
>> +	saved->raw_head = ctb->desc->head;
>> +	saved->raw_tail = ctb->desc->tail;
>> +	saved->head = ctb->head;
>> +	saved->tail = ctb->tail;
>> +	saved->size = ctb->size;
>> +	saved->desc_offset = ((void *)ctb->desc) - blob_ptr;
>> +	saved->cmds_offset = ((void *)ctb->cmds) - blob_ptr;
>> +}
>> +
>>   static struct intel_uc_coredump *
>>   gt_record_uc(struct intel_gt_coredump *gt,
>>   	     struct i915_vma_compress *compress)
>> @@ -1684,9 +1718,16 @@ gt_record_uc(struct intel_gt_coredump *gt,
>>   	 * log times to system times (in conjunction with the error->boottime and
>>   	 * gt->clock_frequency fields saved elsewhere).
>>   	 */
>> -	error_uc->timestamp = intel_uncore_read(gt->_gt->uncore, GUCPMTIMESTAMP);
>> -	error_uc->guc_log = create_vma_coredump(gt->_gt, uc->guc.log.vma,
>> -						"GuC log buffer", compress);
>> +	error_uc->guc.timestamp = intel_uncore_read(gt->_gt->uncore, GUCPMTIMESTAMP);
>> +	error_uc->guc.vma_log = create_vma_coredump(gt->_gt, uc->guc.log.vma,
>> +						    "GuC log buffer", compress);
>> +	error_uc->guc.vma_ctb = create_vma_coredump(gt->_gt, uc->guc.ct.vma,
>> +						    "GuC CT buffer", compress);
>> +	error_uc->guc.last_fence = uc->guc.ct.requests.last_fence;
>> +	gt_record_guc_ctb(error_uc->guc.ctb + 0, &uc->guc.ct.ctbs.send,
>> +			  uc->guc.ct.ctbs.send.desc, (struct intel_guc *)&uc->guc);
>> +	gt_record_guc_ctb(error_uc->guc.ctb + 1, &uc->guc.ct.ctbs.recv,
>> +			  uc->guc.ct.ctbs.send.desc, (struct intel_guc *)&uc->guc);
>>   
>>   	return error_uc;
>>   }
>> @@ -2039,9 +2080,9 @@ __i915_gpu_coredump(struct intel_gt *gt, intel_engine_mask_t engine_mask, u32 du
>>   			error->gt->uc = gt_record_uc(error->gt, compress);
>>   			if (error->gt->uc) {
>>   				if (dump_flags & CORE_DUMP_FLAG_IS_GUC_CAPTURE)
>> -					error->gt->uc->is_guc_capture = true;
>> +					error->gt->uc->guc.is_guc_capture = true;
>>   				else
>> -					GEM_BUG_ON(error->gt->uc->is_guc_capture);
>> +					GEM_BUG_ON(error->gt->uc->guc.is_guc_capture);
>>   			}
>>   		}
>>   
>> diff --git a/drivers/gpu/drm/i915/i915_gpu_error.h b/drivers/gpu/drm/i915/i915_gpu_error.h
>> index d8a8b3d529e09..efc75cc2ffdb9 100644
>> --- a/drivers/gpu/drm/i915/i915_gpu_error.h
>> +++ b/drivers/gpu/drm/i915/i915_gpu_error.h
>> @@ -125,6 +125,15 @@ struct intel_engine_coredump {
>>   	struct intel_engine_coredump *next;
>>   };
>>   
>> +struct intel_ctb_coredump {
>> +	u32 raw_head, head;
>> +	u32 raw_tail, tail;
>> +	u32 raw_status;
>> +	u32 desc_offset;
>> +	u32 cmds_offset;
>> +	u32 size;
>> +};
>> +
>>   struct intel_gt_coredump {
>>   	const struct intel_gt *_gt;
>>   	bool awake;
>> @@ -165,9 +174,14 @@ struct intel_gt_coredump {
>>   	struct intel_uc_coredump {
>>   		struct intel_uc_fw guc_fw;
>>   		struct intel_uc_fw huc_fw;
>> -		struct i915_vma_coredump *guc_log;
>> -		u32 timestamp;
>> -		bool is_guc_capture;
>> +		struct guc_info {
>> +			struct intel_ctb_coredump ctb[2];
>> +			struct i915_vma_coredump *vma_ctb;
>> +			struct i915_vma_coredump *vma_log;
>> +			u32 timestamp;
>> +			u16 last_fence;
>> +			bool is_guc_capture;
>> +		} guc;
>>   	} *uc;
>>   
>>   	struct intel_gt_coredump *next;
>> -- 
>> 2.37.1
>>