From patchwork Thu Sep 9 16:47:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Brost X-Patchwork-Id: 12483475 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=-16.7 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 CAF03C433F5 for ; Thu, 9 Sep 2021 16:53:19 +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 9D9ED61100 for ; Thu, 9 Sep 2021 16:53:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 9D9ED61100 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 8C81C6E8D6; Thu, 9 Sep 2021 16:52:54 +0000 (UTC) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id 293416E8CC; Thu, 9 Sep 2021 16:52:52 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10102"; a="218988848" X-IronPort-AV: E=Sophos;i="5.85,280,1624345200"; d="scan'208";a="218988848" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Sep 2021 09:52:51 -0700 X-IronPort-AV: E=Sophos;i="5.85,280,1624345200"; d="scan'208";a="649003805" Received: from jons-linux-dev-box.fm.intel.com ([10.1.27.20]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Sep 2021 09:52:51 -0700 From: Matthew Brost To: , Cc: , Date: Thu, 9 Sep 2021 09:47:27 -0700 Message-Id: <20210909164744.31249-7-matthew.brost@intel.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210909164744.31249-1-matthew.brost@intel.com> References: <20210909164744.31249-1-matthew.brost@intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 06/23] 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: Reviewed-by: Daniele Ceraolo Spurio --- .../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 31bbfe5479ae..f9e3725b94c1 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -833,17 +833,33 @@ __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) { @@ -862,6 +878,7 @@ 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); } @@ -1598,6 +1615,13 @@ 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); } } @@ -2712,7 +2736,12 @@ 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); }