From patchwork Fri Nov 25 22:30:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andi Shyti X-Patchwork-Id: 13056299 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 1530BC4332F for ; Fri, 25 Nov 2022 22:31:41 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2C60C10E7BD; Fri, 25 Nov 2022 22:31:40 +0000 (UTC) Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by gabe.freedesktop.org (Postfix) with ESMTPS id AB19C10E7B3; Fri, 25 Nov 2022 22:31:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1669415462; x=1700951462; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=AWUkZGt+3tqgzjRcQ3JTzILsYfQEaIXI6NIKRYGtCaY=; b=UfSNVlWDxdS7RjOVnSWu7kqL5gGySfkkTMXCAe0DY9va0mWBXSWV8tIf XShxSF46t4/zqWRFZdqRbBQQOicltLXd/IqX6ceRxfFwtY1vT+WKzJL1i XtFBgbccctJBSsmf69o8v87y5Msl+t1b/bD9aISJgbHDdLobxU7TRr33w x5A6t7xLOKJDNY4pCI11cGMacgzt6+z+BfgkKZ3PfLNTF59vq/sKh/TQH Ro2G+vgTLCaa6ee0H7dD7iNNHnfDnGJuCcV3I3IogI7N+G6MFN0LMNidM ebPMXskTorMkr9JWv6ukQseqKvwtfRV9U1+isXELrC/Ps9wUPWrwbgKD+ w==; X-IronPort-AV: E=McAfee;i="6500,9779,10542"; a="294931102" X-IronPort-AV: E=Sophos;i="5.96,194,1665471600"; d="scan'208";a="294931102" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Nov 2022 14:31:01 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10542"; a="767467431" X-IronPort-AV: E=Sophos;i="5.96,194,1665471600"; d="scan'208";a="767467431" Received: from ncataldi-mobl.ger.corp.intel.com (HELO intel.com) ([10.252.50.225]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Nov 2022 14:30:59 -0800 From: Andi Shyti To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Date: Fri, 25 Nov 2022 23:30:27 +0100 Message-Id: <20221125223029.323339-4-andi.shyti@linux.intel.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221125223029.323339-1-andi.shyti@linux.intel.com> References: <20221125223029.323339-1-andi.shyti@linux.intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v3 3/5] drm/i915: Refine VT-d scanout workaround 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: , Cc: =?utf-8?q?Thomas_Hellstr=C3=B6m?= , Chris Wilson , Matthew Auld Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" From: Chris Wilson VT-d may cause overfetch of the scanout PTE, both before and after the vma (depending on the scanout orientation). bspec recommends that we provide a tile-row in either directions, and suggests using 168 PTE, warning that the accesses will wrap around the ends of the GGTT. Currently, we fill the entire GGTT with scratch pages when using VT-d to always ensure there are valid entries around every vma, including scanout. However, writing every PTE is slow as on recent devices we perform 8MiB of uncached writes, incurring an extra 100ms during resume. If instead we focus on only putting guard pages around scanout, we can avoid touching the whole GGTT. To avoid having to introduce extra nodes around each scanout vma, we adjust the scanout drm_mm_node to be smaller than the allocated space, and fixup the extra PTE during dma binding. Signed-off-by: Chris Wilson Signed-off-by: Tejas Upadhyay Signed-off-by: Tvrtko Ursulin Signed-off-by: Andi Shyti --- drivers/gpu/drm/i915/gem/i915_gem_domain.c | 13 +++++++++++ drivers/gpu/drm/i915/gt/intel_ggtt.c | 25 +--------------------- 2 files changed, 14 insertions(+), 24 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c index d44a152ce6800..882b91519f92b 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c @@ -17,6 +17,8 @@ #include "i915_gem_object.h" #include "i915_vma.h" +#define VTD_GUARD (168u * I915_GTT_PAGE_SIZE) /* 168 or tile-row PTE padding */ + static bool gpu_write_needs_clflush(struct drm_i915_gem_object *obj) { struct drm_i915_private *i915 = to_i915(obj->base.dev); @@ -424,6 +426,17 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj, if (ret) return ERR_PTR(ret); + /* VT-d may overfetch before/after the vma, so pad with scratch */ + if (intel_scanout_needs_vtd_wa(i915)) { + unsigned int guard = VTD_GUARD; + + if (i915_gem_object_is_tiled(obj)) + guard = max(guard, + i915_gem_object_get_tile_row_size(obj)); + + flags |= PIN_OFFSET_GUARD | guard; + } + /* * As the user may map the buffer once pinned in the display plane * (e.g. libkms for the bootup splash), we have to ensure that we diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c index 133710258eae6..5ccec5c9206d2 100644 --- a/drivers/gpu/drm/i915/gt/intel_ggtt.c +++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c @@ -367,27 +367,6 @@ static void nop_clear_range(struct i915_address_space *vm, { } -static void gen8_ggtt_clear_range(struct i915_address_space *vm, - u64 start, u64 length) -{ - struct i915_ggtt *ggtt = i915_vm_to_ggtt(vm); - unsigned int first_entry = start / I915_GTT_PAGE_SIZE; - unsigned int num_entries = length / I915_GTT_PAGE_SIZE; - const gen8_pte_t scratch_pte = vm->scratch[0]->encode; - gen8_pte_t __iomem *gtt_base = - (gen8_pte_t __iomem *)ggtt->gsm + first_entry; - const int max_entries = ggtt_total_entries(ggtt) - first_entry; - int i; - - if (WARN(num_entries > max_entries, - "First entry = %d; Num entries = %d (max=%d)\n", - first_entry, num_entries, max_entries)) - num_entries = max_entries; - - for (i = 0; i < num_entries; i++) - gen8_set_pte(>t_base[i], scratch_pte); -} - static void bxt_vtd_ggtt_wa(struct i915_address_space *vm) { /* @@ -959,8 +938,6 @@ static int gen8_gmch_probe(struct i915_ggtt *ggtt) ggtt->vm.cleanup = gen6_gmch_remove; ggtt->vm.insert_page = gen8_ggtt_insert_page; ggtt->vm.clear_range = nop_clear_range; - if (intel_scanout_needs_vtd_wa(i915)) - ggtt->vm.clear_range = gen8_ggtt_clear_range; ggtt->vm.insert_entries = gen8_ggtt_insert_entries; @@ -1121,7 +1098,7 @@ static int gen6_gmch_probe(struct i915_ggtt *ggtt) ggtt->vm.alloc_scratch_dma = alloc_pt_dma; ggtt->vm.clear_range = nop_clear_range; - if (!HAS_FULL_PPGTT(i915) || intel_scanout_needs_vtd_wa(i915)) + if (!HAS_FULL_PPGTT(i915)) ggtt->vm.clear_range = gen6_ggtt_clear_range; ggtt->vm.insert_page = gen6_ggtt_insert_page; ggtt->vm.insert_entries = gen6_ggtt_insert_entries;