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,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 60786C432BE for ; Sun, 15 Aug 2021 20:21:42 +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 32C446120E for ; Sun, 15 Aug 2021 20:21:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 32C446120E 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 E6F3C89D99; Sun, 15 Aug 2021 20:21:34 +0000 (UTC) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id 197B689175 for ; Sun, 15 Aug 2021 20:21:21 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10077"; a="213914005" X-IronPort-AV: E=Sophos;i="5.84,324,1620716400"; d="scan'208";a="213914005" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2021 13:21:18 -0700 X-IronPort-AV: E=Sophos;i="5.84,324,1620716400"; d="scan'208";a="461849463" Received: from jons-linux-dev-box.fm.intel.com ([10.1.27.20]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Aug 2021 13:21:18 -0700 From: Matthew Brost To: , drmdevel@freedesktop.org Cc: Date: Sun, 15 Aug 2021 13:15:43 -0700 Message-Id: <20210815201559.1150-6-matthew.brost@intel.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210815201559.1150-1-matthew.brost@intel.com> References: <20210815201559.1150-1-matthew.brost@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Intel-gfx] [PATCH 05/21] 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 cancelation the context reset G2H is received after schedule disable done G2H which is likely the wrong order. The schedule disable done G2H release the waiting request cancelation 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 cancelation code owns the resubmit. Use some clever tricks of checking the context state to seal this race until if / when the GuC firmware is fixed. Fixes: 62eaf0ae217d ("drm/i915/guc: Support request cancellation") Signed-off-by: Matthew Brost Cc: --- .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 42 ++++++++++++++++--- 1 file changed, 36 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 3cd2da6f5c03..1e6b876bab34 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -826,17 +826,34 @@ __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 cancelation + * this G2H is received after the schedule disable complete G2H which is + * likely wrong as this creates a race between the request cancelation + * code re-submitting the context and this G2H handler. This likely + * should be fixed in the GuC but until if / when that gets fixed we + * need to workaround this. Convert this function to a NOP if a pending + * enable is in flight as this indicates that a request cancelation has + * occured. */ - clr_context_enabled(ce); + spin_lock_irqsave(&ce->guc_state.lock, flags); + if (unlikely(!context_pending_enable(ce))) { + clr_context_enabled(ce); + 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) { @@ -855,6 +872,7 @@ 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); } @@ -1599,6 +1617,13 @@ 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); } } @@ -2719,7 +2744,12 @@ 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 cancelation 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