[PATCH v3 3/6] drm/xe: Store xe_he_engine in xe_hw_engine_snapshot

[Matt Roper]

On Mon, Jan 29, 2024 at 10:17:39AM -0800, José Roberto de Souza wrote:
> A future patch will require gt and xe device structs, so here
> replacing class by hwe.

I thought this didn't work because in cases like a failure during probe
the the devcoredump can persist for a while after the xe_device (and
xe_gt, and xe_hw_engine) have all been kfree'd?

I.e., we can use the GT or HWE during the capture phase, but by the time
we get to the print phase they may already have been deallocated and we
can't touch anything except the data we've already stashed away locally?


Matt

> 
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Matt Roper <matthew.d.roper at intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_hw_engine.c       | 6 +++---
>  drivers/gpu/drm/xe/xe_hw_engine_types.h | 4 ++--
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_hw_engine.c b/drivers/gpu/drm/xe/xe_hw_engine.c
> index 0d17e32d70c87..61b0c18d8b624 100644
> --- a/drivers/gpu/drm/xe/xe_hw_engine.c
> +++ b/drivers/gpu/drm/xe/xe_hw_engine.c
> @@ -760,7 +760,7 @@ xe_hw_engine_snapshot_capture(struct xe_hw_engine *hwe)
>  		return NULL;
>  
>  	snapshot->name = kstrdup(hwe->name, GFP_ATOMIC);
> -	snapshot->class = hwe->class;
> +	snapshot->hwe = hwe;
>  	snapshot->logical_instance = hwe->logical_instance;
>  	snapshot->forcewake.domain = hwe->domain;
>  	snapshot->forcewake.ref = xe_force_wake_ref(gt_to_fw(hwe->gt),
> @@ -807,7 +807,7 @@ xe_hw_engine_snapshot_capture(struct xe_hw_engine *hwe)
>  	snapshot->reg.ring_eir = hw_engine_mmio_read32(hwe, RING_EIR(0));
>  	snapshot->reg.ipehr = hw_engine_mmio_read32(hwe, RING_IPEHR(0));
>  
> -	if (snapshot->class == XE_ENGINE_CLASS_COMPUTE)
> +	if (snapshot->hwe->class == XE_ENGINE_CLASS_COMPUTE)
>  		snapshot->reg.rcu_mode = xe_mmio_read32(hwe->gt, RCU_MODE);
>  
>  	return snapshot;
> @@ -852,7 +852,7 @@ void xe_hw_engine_snapshot_print(struct xe_hw_engine_snapshot *snapshot,
>  	drm_printf(p, "\tBBADDR: 0x%016llx\n", snapshot->reg.ring_bbaddr);
>  	drm_printf(p, "\tDMA_FADDR: 0x%016llx\n", snapshot->reg.ring_dma_fadd);
>  	drm_printf(p, "\tIPEHR: 0x%08x\n", snapshot->reg.ipehr);
> -	if (snapshot->class == XE_ENGINE_CLASS_COMPUTE)
> +	if (snapshot->hwe->class == XE_ENGINE_CLASS_COMPUTE)
>  		drm_printf(p, "\tRCU_MODE: 0x%08x\n",
>  			   snapshot->reg.rcu_mode);
>  }
> diff --git a/drivers/gpu/drm/xe/xe_hw_engine_types.h b/drivers/gpu/drm/xe/xe_hw_engine_types.h
> index d7f828c76cc5f..27deaa31efd31 100644
> --- a/drivers/gpu/drm/xe/xe_hw_engine_types.h
> +++ b/drivers/gpu/drm/xe/xe_hw_engine_types.h
> @@ -158,8 +158,8 @@ struct xe_hw_engine {
>  struct xe_hw_engine_snapshot {
>  	/** @name: name of the hw engine */
>  	char *name;
> -	/** @class: class of this hw engine */
> -	enum xe_engine_class class;
> +	/** @hwe: hw engine */
> +	struct xe_hw_engine *hwe;
>  	/** @logical_instance: logical instance of this hw engine */
>  	u16 logical_instance;
>  	/** @forcewake: Force Wake information snapshot */
> -- 
> 2.43.0
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation