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

[John Harrison <john.c.harrison@xxxxxxxxx>]

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@xxxxxxxxx>
>   
> On Wed, 2022-07-27 at 19:20 -0700, John.C.Harrison@xxxxxxxxx wrote:
> > From: John Harrison <John.C.Harrison@xxxxxxxxx>
> >
> > 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@xxxxxxxxx>
> > ---
> >   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