diff mbox series

drm/i915/huc: stall media submission until HuC is loaded

Message ID 20220913232212.894826-1-daniele.ceraolospurio@intel.com (mailing list archive)
State New, archived
Headers show
Series drm/i915/huc: stall media submission until HuC is loaded | expand

Commit Message

Daniele Ceraolo Spurio Sept. 13, 2022, 11:22 p.m. UTC
Wait on the fence to be signalled to avoid the submissions finding HuC
not yet loaded.

v2: use dedicaded wait_queue_entry for waiting in HuC load, as submitq
can't be re-used for it.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tony Ye <tony.ye@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com> #v1
Acked-by: Tony Ye <tony.ye@intel.com>
---
 drivers/gpu/drm/i915/gt/uc/intel_huc.h |  6 ++++++
 drivers/gpu/drm/i915/i915_request.c    | 24 ++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_request.h    |  5 +++++
 3 files changed, 35 insertions(+)

Comments

Alan Previn Sept. 27, 2022, 6:54 p.m. UTC | #1
On Tue, 2022-09-13 at 16:22 -0700, Ceraolo Spurio, Daniele wrote:
> Wait on the fence to be signalled to avoid the submissions finding HuC
> not yet loaded.
> 
> v2: use dedicaded wait_queue_entry for waiting in HuC load, as submitq
> can't be re-used for it.
> 
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Cc: Tony Ye <tony.ye@intel.com>
> Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com> #v1
> Acked-by: Tony Ye <tony.ye@intel.com>
> ---
>  drivers/gpu/drm/i915/gt/uc/intel_huc.h |  6 ++++++
>  drivers/gpu/drm/i915/i915_request.c    | 24 ++++++++++++++++++++++++
>  drivers/gpu/drm/i915/i915_request.h    |  5 +++++
>  3 files changed, 35 insertions(+)
> 
[snip]

> diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
> index 47041ec68df8..f5e1bb5e857a 100644
> --- a/drivers/gpu/drm/i915/i915_request.h
> +++ b/drivers/gpu/drm/i915/i915_request.h
> @@ -348,6 +348,11 @@ struct i915_request {
>  #define	GUC_PRIO_FINI	0xfe
>  	u8 guc_prio;
>  
> +	/**
> +	 * @hucq: wait queue entry used to wait on the HuC load to complete
> +	 */
> +	wait_queue_entry_t hucq;
> +
> 
> 
I believe that in future if we have multiple engines that
requires a similiar stalled initialization wait, we should
have an array of ptrs here and a not-huc-specific-helper that
can sort out adding fence-signalled-waiters. But for now this is
a very rare race condition that only happens with HuC so
this hucq specific wait-entry will do fine. Thus:


Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_huc.h b/drivers/gpu/drm/i915/gt/uc/intel_huc.h
index 915d281c1c72..52db03620c60 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_huc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_huc.h
@@ -81,6 +81,12 @@  static inline bool intel_huc_is_loaded_by_gsc(const struct intel_huc *huc)
 	return huc->fw.loaded_via_gsc;
 }
 
+static inline bool intel_huc_wait_required(struct intel_huc *huc)
+{
+	return intel_huc_is_used(huc) && intel_huc_is_loaded_by_gsc(huc) &&
+	       !intel_huc_is_authenticated(huc);
+}
+
 void intel_huc_load_status(struct intel_huc *huc, struct drm_printer *p);
 
 #endif
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 62fad16a55e8..f949a9495758 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -1621,6 +1621,20 @@  i915_request_await_object(struct i915_request *to,
 	return ret;
 }
 
+static void i915_request_await_huc(struct i915_request *rq)
+{
+	struct intel_huc *huc = &rq->context->engine->gt->uc.huc;
+
+	/* don't stall kernel submissions! */
+	if (!rcu_access_pointer(rq->context->gem_context))
+		return;
+
+	if (intel_huc_wait_required(huc))
+		i915_sw_fence_await_sw_fence(&rq->submit,
+					     &huc->delayed_load.fence,
+					     &rq->hucq);
+}
+
 static struct i915_request *
 __i915_request_ensure_parallel_ordering(struct i915_request *rq,
 					struct intel_timeline *timeline)
@@ -1702,6 +1716,16 @@  __i915_request_add_to_timeline(struct i915_request *rq)
 	struct intel_timeline *timeline = i915_request_timeline(rq);
 	struct i915_request *prev;
 
+	/*
+	 * Media workloads may require HuC, so stall them until HuC loading is
+	 * complete. Note that HuC not being loaded when a user submission
+	 * arrives can only happen when HuC is loaded via GSC and in that case
+	 * we still expect the window between us starting to accept submissions
+	 * and HuC loading completion to be small (a few hundred ms).
+	 */
+	if (rq->engine->class == VIDEO_DECODE_CLASS)
+		i915_request_await_huc(rq);
+
 	/*
 	 * Dependency tracking and request ordering along the timeline
 	 * is special cased so that we can eliminate redundant ordering
diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
index 47041ec68df8..f5e1bb5e857a 100644
--- a/drivers/gpu/drm/i915/i915_request.h
+++ b/drivers/gpu/drm/i915/i915_request.h
@@ -348,6 +348,11 @@  struct i915_request {
 #define	GUC_PRIO_FINI	0xfe
 	u8 guc_prio;
 
+	/**
+	 * @hucq: wait queue entry used to wait on the HuC load to complete
+	 */
+	wait_queue_entry_t hucq;
+
 	I915_SELFTEST_DECLARE(struct {
 		struct list_head link;
 		unsigned long delay;