[Intel-gfx] [PATCH v4 12/17] drm/i915/pxp: start the arb session on demand

Rodrigo Vivi rodrigo.vivi at intel.com
Wed Jun 2 18:14:00 UTC 2021


On Mon, May 24, 2021 at 10:47:58PM -0700, Daniele Ceraolo Spurio wrote:
> Now that we can handle destruction and re-creation of the arb session,
> we can postpone the start of the session to the first submission that
> requires it, to avoid keeping it running with no user.
> 
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> ---
>  .../gpu/drm/i915/gem/i915_gem_execbuffer.c    |  8 ++--
>  drivers/gpu/drm/i915/pxp/intel_pxp.c          | 37 ++++++++++++-------
>  drivers/gpu/drm/i915/pxp/intel_pxp.h          |  4 +-
>  drivers/gpu/drm/i915/pxp/intel_pxp_irq.c      |  2 +-
>  drivers/gpu/drm/i915/pxp/intel_pxp_session.c  |  6 +--
>  drivers/gpu/drm/i915/pxp/intel_pxp_tee.c      | 10 +----
>  drivers/gpu/drm/i915/pxp/intel_pxp_types.h    |  3 ++
>  7 files changed, 39 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> index a11e9d5767bf..c08e28847064 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> @@ -2948,9 +2948,11 @@ eb_select_engine(struct i915_execbuffer *eb)
>  	intel_gt_pm_get(ce->engine->gt);
>  
>  	if (i915_gem_context_uses_protected_content(eb->gem_context)) {
> -		err = intel_pxp_wait_for_arb_start(&ce->engine->gt->pxp);
> -		if (err)
> -			goto err;
> +		if (!intel_pxp_is_active(&ce->engine->gt->pxp)) {
> +			err = intel_pxp_start(&ce->engine->gt->pxp);
> +			if (err)
> +				goto err;
> +		}
>  
>  		if (i915_gem_context_invalidated(eb->gem_context)) {
>  			err = -EACCES;
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.c b/drivers/gpu/drm/i915/pxp/intel_pxp.c
> index f713d3423cea..2291c68fd3a0 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp.c
> @@ -77,6 +77,7 @@ void intel_pxp_init(struct intel_pxp *pxp)
>  	init_completion(&pxp->termination);
>  	complete_all(&pxp->termination);
>  
> +	mutex_init(&pxp->arb_mutex);
>  	INIT_WORK(&pxp->session_work, intel_pxp_session_work);
>  
>  	ret = create_vcs_context(pxp);
> @@ -113,7 +114,7 @@ void intel_pxp_mark_termination_in_progress(struct intel_pxp *pxp)
>  	reinit_completion(&pxp->termination);
>  }
>  
> -static void intel_pxp_queue_termination(struct intel_pxp *pxp)
> +static void pxp_queue_termination(struct intel_pxp *pxp)
>  {
>  	struct intel_gt *gt = pxp_to_gt(pxp);
>  
> @@ -132,31 +133,41 @@ static void intel_pxp_queue_termination(struct intel_pxp *pxp)
>   * the arb session is restarted from the irq work when we receive the
>   * termination completion interrupt
>   */
> -int intel_pxp_wait_for_arb_start(struct intel_pxp *pxp)
> +int intel_pxp_start(struct intel_pxp *pxp)
>  {
> +	int ret = 0;
> +
>  	if (!intel_pxp_is_enabled(pxp))
> -		return 0;
> +		return -ENODEV;
> +
> +	mutex_lock(&pxp->arb_mutex);
> +
> +	if (pxp->arb_is_valid)
> +		goto unlock;
> +
> +	pxp_queue_termination(pxp);
>  
>  	if (!wait_for_completion_timeout(&pxp->termination,
> -					 msecs_to_jiffies(100)))
> -		return -ETIMEDOUT;
> +					msecs_to_jiffies(100))) {
> +		ret = -ETIMEDOUT;
> +		goto unlock;
> +	}
> +
> +	/* make sure the compiler doesn't optimize the double access */
> +	barrier();
>  
>  	if (!pxp->arb_is_valid)
> -		return -EIO;
> +		ret = -EIO;
>  
> -	return 0;
> +unlock:
> +	mutex_unlock(&pxp->arb_mutex);
> +	return ret;
>  }
>  
>  void intel_pxp_init_hw(struct intel_pxp *pxp)
>  {
>  	kcr_pxp_enable(pxp_to_gt(pxp));
>  	intel_pxp_irq_enable(pxp);
> -
> -	/*
> -	 * the session could've been attacked while we weren't loaded, so
> -	 * handle it as if it was and re-create it.
> -	 */
> -	intel_pxp_queue_termination(pxp);
>  }
>  
>  void intel_pxp_fini_hw(struct intel_pxp *pxp)
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp.h b/drivers/gpu/drm/i915/pxp/intel_pxp.h
> index 91c1a2056309..1f9871e64096 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp.h
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp.h
> @@ -32,7 +32,7 @@ void intel_pxp_init_hw(struct intel_pxp *pxp);
>  void intel_pxp_fini_hw(struct intel_pxp *pxp);
>  
>  void intel_pxp_mark_termination_in_progress(struct intel_pxp *pxp);
> -int intel_pxp_wait_for_arb_start(struct intel_pxp *pxp);
> +int intel_pxp_start(struct intel_pxp *pxp);
>  void intel_pxp_invalidate(struct intel_pxp *pxp);
>  #else
>  static inline void intel_pxp_init(struct intel_pxp *pxp)
> @@ -43,7 +43,7 @@ static inline void intel_pxp_fini(struct intel_pxp *pxp)
>  {
>  }
>  
> -static inline int intel_pxp_wait_for_arb_start(struct intel_pxp *pxp)
> +static inline int intel_pxp_start(struct intel_pxp *pxp)
>  {
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_irq.c b/drivers/gpu/drm/i915/pxp/intel_pxp_irq.c
> index 196449243515..a230d0034e50 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_irq.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_irq.c
> @@ -31,7 +31,7 @@ void intel_pxp_irq_handler(struct intel_pxp *pxp, u16 iir)
>  		   GEN12_DISPLAY_APP_TERMINATED_PER_FW_REQ_INTERRUPT)) {
>  		/* immediately mark PXP as inactive on termination */
>  		intel_pxp_mark_termination_in_progress(pxp);
> -		pxp->session_events |= PXP_TERMINATION_REQUEST;
> +		pxp->session_events |= PXP_TERMINATION_REQUEST | PXP_INVAL_REQUIRED;
>  	}
>  
>  	if (iir & GEN12_DISPLAY_STATE_RESET_COMPLETE_INTERRUPT)
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_session.c b/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
> index e9fe757e368a..c21620916710 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
> @@ -85,9 +85,6 @@ static int pxp_terminate_arb_session_and_global(struct intel_pxp *pxp)
>  	/* must mark termination in progress calling this function */
>  	GEM_WARN_ON(pxp->arb_is_valid);
>  
> -	/* invalidate protected objects */
> -	intel_pxp_invalidate(pxp);
> -
>  	/* terminate the hw sessions */
>  	ret = intel_pxp_terminate_session(pxp, ARB_SESSION);
>  	if (ret) {
> @@ -144,6 +141,9 @@ void intel_pxp_session_work(struct work_struct *work)
>  	if (!events)
>  		return;
>  
> +	if (events & PXP_INVAL_REQUIRED)
> +		intel_pxp_invalidate(pxp);
> +

doesn't this invalidation change deserves a separated patch?
I'm not sure if I understood why we need this change...

>  	if (events & PXP_TERMINATION_REQUEST) {
>  		events &= ~PXP_TERMINATION_COMPLETE;
>  		pxp_terminate(pxp);
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c b/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
> index e3d178c44e51..35b3fed4ca2f 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_tee.c
> @@ -63,23 +63,15 @@ static int intel_pxp_tee_io_message(struct intel_pxp *pxp,
>  static int i915_pxp_tee_component_bind(struct device *i915_kdev,
>  				       struct device *tee_kdev, void *data)
>  {
> -	struct drm_i915_private *i915 = kdev_to_i915(i915_kdev);
>  	struct intel_pxp *pxp = i915_dev_to_pxp(i915_kdev);
> -	int ret;
>  
>  	pxp->pxp_component = data;
>  	pxp->pxp_component->tee_dev = tee_kdev;
>  
>  	/* the component is required to fully start the PXP HW */
>  	intel_pxp_init_hw(pxp);
> -	ret = intel_pxp_wait_for_arb_start(pxp);
> -	if (ret) {
> -		drm_err(&i915->drm, "Failed to create arb session during bind\n");
> -		intel_pxp_fini_hw(pxp);
> -		pxp->pxp_component = NULL;
> -	}
>  
> -	return ret;
> +	return 0;
>  }
>  
>  static void i915_pxp_tee_component_unbind(struct device *i915_kdev,
> diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_types.h b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> index c059a17cbcfe..b3ae49dd73a8 100644
> --- a/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> @@ -7,6 +7,7 @@
>  #define __INTEL_PXP_TYPES_H__
>  
>  #include <linux/completion.h>
> +#include <linux/mutex.h>
>  #include <linux/types.h>
>  #include <linux/workqueue.h>
>  
> @@ -23,6 +24,7 @@ struct intel_pxp {
>  	 * even if the keys are gone, so we can't rely on the HW state of the
>  	 * session to know if it's valid and need to track the status in SW.
>  	 */
> +	struct mutex arb_mutex; /* protects arb session start */
>  	bool arb_is_valid;
>  
>  	/*
> @@ -40,6 +42,7 @@ struct intel_pxp {
>  	u32 session_events; /* protected with gt->irq_lock */
>  #define PXP_TERMINATION_REQUEST  BIT(0)
>  #define PXP_TERMINATION_COMPLETE BIT(1)
> +#define PXP_INVAL_REQUIRED       BIT(2)
>  };
>  
>  #endif /* __INTEL_PXP_TYPES_H__ */
> -- 
> 2.29.2
> 
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