From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A184C432BE for ; Thu, 26 Aug 2021 03:29:17 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F1E8D610CB for ; Thu, 26 Aug 2021 03:29:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org F1E8D610CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 52DA96E4C9; Thu, 26 Aug 2021 03:28:43 +0000 (UTC) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4F8976E4B6; Thu, 26 Aug 2021 03:28:41 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10087"; a="215811064" X-IronPort-AV: E=Sophos;i="5.84,352,1620716400"; d="scan'208";a="215811064" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2021 20:28:40 -0700 X-IronPort-AV: E=Sophos;i="5.84,352,1620716400"; d="scan'208";a="684738533" Received: from jons-linux-dev-box.fm.intel.com ([10.1.27.20]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2021 20:28:39 -0700 From: Matthew Brost To: , Cc: Subject: [PATCH 06/27] drm/i915/guc: Workaround reset G2H is received after schedule done G2H Date: Wed, 25 Aug 2021 20:23:06 -0700 Message-Id: <20210826032327.18078-7-matthew.brost@intel.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210826032327.18078-1-matthew.brost@intel.com> References: <20210826032327.18078-1-matthew.brost@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" If the context is reset as a result of the request cancellation the context reset G2H is received after schedule disable done G2H which is the wrong order. The schedule disable done G2H release the waiting request cancellation code which resubmits the context. This races with the context reset G2H which also wants to resubmit the context but in this case it really should be a NOP as request cancellation code owns the resubmit. Use some clever tricks of checking the context state to seal this race until the GuC firmware is fixed. v2: (Checkpatch) - Fix typos v3: (Daniele) - State that is a bug in the GuC firmware Fixes: 62eaf0ae217d ("drm/i915/guc: Support request cancellation") Signed-off-by: Matthew Brost Cc: --- .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 41 ++++++++++++++++--- 1 file changed, 35 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index d94e7e1a876f..592b421e1429 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -831,17 +831,33 @@ __unwind_incomplete_requests(struct intel_context *ce) static void __guc_reset_context(struct intel_context *ce, bool stalled) { struct i915_request *rq; + unsigned long flags; u32 head; + bool skip = false; intel_context_get(ce); /* - * GuC will implicitly mark the context as non-schedulable - * when it sends the reset notification. Make sure our state - * reflects this change. The context will be marked enabled - * on resubmission. + * GuC will implicitly mark the context as non-schedulable when it sends + * the reset notification. Make sure our state reflects this change. The + * context will be marked enabled on resubmission. + * + * XXX: If the context is reset as a result of the request cancellation + * this G2H is received after the schedule disable complete G2H which is + * wrong as this creates a race between the request cancellation code + * re-submitting the context and this G2H handler. This is a bug in the + * GuC but can be worked around in the meantime but converting this to a + * NOP if a pending enable is in flight as this indicates that a request + * cancellation has occurred. */ - clr_context_enabled(ce); + spin_lock_irqsave(&ce->guc_state.lock, flags); + if (likely(!context_pending_enable(ce))) + clr_context_enabled(ce); + else + skip = true; + spin_unlock_irqrestore(&ce->guc_state.lock, flags); + if (unlikely(skip)) + goto out_put; rq = intel_context_find_active_request(ce); if (!rq) { @@ -860,6 +876,7 @@ static void __guc_reset_context(struct intel_context *ce, bool stalled) out_replay: guc_reset_state(ce, head, stalled); __unwind_incomplete_requests(ce); +out_put: intel_context_put(ce); } @@ -1604,6 +1621,13 @@ static void guc_context_cancel_request(struct intel_context *ce, guc_reset_state(ce, intel_ring_wrap(ce->ring, rq->head), true); } + + /* + * XXX: Racey if context is reset, see comment in + * __guc_reset_context(). + */ + flush_work(&ce_to_guc(ce)->ct.requests.worker); + guc_context_unblock(ce); } } @@ -2718,7 +2742,12 @@ static void guc_handle_context_reset(struct intel_guc *guc, { trace_intel_context_reset(ce); - if (likely(!intel_context_is_banned(ce))) { + /* + * XXX: Racey if request cancellation has occurred, see comment in + * __guc_reset_context(). + */ + if (likely(!intel_context_is_banned(ce) && + !context_blocked(ce))) { capture_error_state(guc, ce); guc_context_replay(ce); } -- 2.32.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 557BFC432BE for ; Thu, 26 Aug 2021 03:29:28 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 22603610A7 for ; Thu, 26 Aug 2021 03:29:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 22603610A7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8D5AE6E507; Thu, 26 Aug 2021 03:28:47 +0000 (UTC) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4F8976E4B6; Thu, 26 Aug 2021 03:28:41 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10087"; a="215811064" X-IronPort-AV: E=Sophos;i="5.84,352,1620716400"; d="scan'208";a="215811064" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2021 20:28:40 -0700 X-IronPort-AV: E=Sophos;i="5.84,352,1620716400"; d="scan'208";a="684738533" Received: from jons-linux-dev-box.fm.intel.com ([10.1.27.20]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Aug 2021 20:28:39 -0700 From: Matthew Brost To: , Cc: Date: Wed, 25 Aug 2021 20:23:06 -0700 Message-Id: <20210826032327.18078-7-matthew.brost@intel.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210826032327.18078-1-matthew.brost@intel.com> References: <20210826032327.18078-1-matthew.brost@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Intel-gfx] [PATCH 06/27] drm/i915/guc: Workaround reset G2H is received after schedule done G2H X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" If the context is reset as a result of the request cancellation the context reset G2H is received after schedule disable done G2H which is the wrong order. The schedule disable done G2H release the waiting request cancellation code which resubmits the context. This races with the context reset G2H which also wants to resubmit the context but in this case it really should be a NOP as request cancellation code owns the resubmit. Use some clever tricks of checking the context state to seal this race until the GuC firmware is fixed. v2: (Checkpatch) - Fix typos v3: (Daniele) - State that is a bug in the GuC firmware Fixes: 62eaf0ae217d ("drm/i915/guc: Support request cancellation") Signed-off-by: Matthew Brost Cc: --- .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 41 ++++++++++++++++--- 1 file changed, 35 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index d94e7e1a876f..592b421e1429 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -831,17 +831,33 @@ __unwind_incomplete_requests(struct intel_context *ce) static void __guc_reset_context(struct intel_context *ce, bool stalled) { struct i915_request *rq; + unsigned long flags; u32 head; + bool skip = false; intel_context_get(ce); /* - * GuC will implicitly mark the context as non-schedulable - * when it sends the reset notification. Make sure our state - * reflects this change. The context will be marked enabled - * on resubmission. + * GuC will implicitly mark the context as non-schedulable when it sends + * the reset notification. Make sure our state reflects this change. The + * context will be marked enabled on resubmission. + * + * XXX: If the context is reset as a result of the request cancellation + * this G2H is received after the schedule disable complete G2H which is + * wrong as this creates a race between the request cancellation code + * re-submitting the context and this G2H handler. This is a bug in the + * GuC but can be worked around in the meantime but converting this to a + * NOP if a pending enable is in flight as this indicates that a request + * cancellation has occurred. */ - clr_context_enabled(ce); + spin_lock_irqsave(&ce->guc_state.lock, flags); + if (likely(!context_pending_enable(ce))) + clr_context_enabled(ce); + else + skip = true; + spin_unlock_irqrestore(&ce->guc_state.lock, flags); + if (unlikely(skip)) + goto out_put; rq = intel_context_find_active_request(ce); if (!rq) { @@ -860,6 +876,7 @@ static void __guc_reset_context(struct intel_context *ce, bool stalled) out_replay: guc_reset_state(ce, head, stalled); __unwind_incomplete_requests(ce); +out_put: intel_context_put(ce); } @@ -1604,6 +1621,13 @@ static void guc_context_cancel_request(struct intel_context *ce, guc_reset_state(ce, intel_ring_wrap(ce->ring, rq->head), true); } + + /* + * XXX: Racey if context is reset, see comment in + * __guc_reset_context(). + */ + flush_work(&ce_to_guc(ce)->ct.requests.worker); + guc_context_unblock(ce); } } @@ -2718,7 +2742,12 @@ static void guc_handle_context_reset(struct intel_guc *guc, { trace_intel_context_reset(ce); - if (likely(!intel_context_is_banned(ce))) { + /* + * XXX: Racey if request cancellation has occurred, see comment in + * __guc_reset_context(). + */ + if (likely(!intel_context_is_banned(ce) && + !context_blocked(ce))) { capture_error_state(guc, ce); guc_context_replay(ce); } -- 2.32.0