From patchwork Wed Nov 9 16:49:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andi Shyti X-Patchwork-Id: 13037745 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 B457AC4332F for ; Wed, 9 Nov 2022 16:50:08 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9F01E10E610; Wed, 9 Nov 2022 16:50:07 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id 50ADE10E5F9; Wed, 9 Nov 2022 16:50:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1668012601; x=1699548601; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=qJU3uJ3VslMCDzaEqfIEADwarHjBELcUhV3fwujfOuw=; b=BPTscYiZLlWE42189MK3TQrvrh2pvr5o7saOlk1cHmYb05N4mZbf5C5X ntOevDvhY9qtOtajOCooXQ2TsB1VH4+RMvj17ZgYL4bteHSa9X4H7qFNk 0yMeniYtJ19r+m+Rh6MQYk1a/ick6mRIw+8ZK2mo9xseVnZvbDM6zg3I1 xhbbb1lItERCf1eSnCtcWpyu+76VAfFfFDC/f9RsHLXUDfz3cgdh40L1C E0GJ9KA6AtyWlti5mta4Ebsctl8P5x6u0M+KTgK/v/86OIidfypQAioHq 6GzELsqC9J7ungX7CrErRF/Y4npecWF1b5UW5BHjjBrXuOCQHEuGKJc+n w==; X-IronPort-AV: E=McAfee;i="6500,9779,10526"; a="311026257" X-IronPort-AV: E=Sophos;i="5.96,151,1665471600"; d="scan'208";a="311026257" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Nov 2022 08:49:47 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10526"; a="670014027" X-IronPort-AV: E=Sophos;i="5.96,151,1665471600"; d="scan'208";a="670014027" Received: from dvorobye-mobl.ccr.corp.intel.com (HELO intel.com) ([10.252.32.169]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Nov 2022 08:49:44 -0800 From: Andi Shyti To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: [PATCH 3/3] drm/i915: Refine VT-d scanout workaround Date: Wed, 9 Nov 2022 17:49:13 +0100 Message-Id: <20221109164913.909323-4-andi.shyti@linux.intel.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20221109164913.909323-1-andi.shyti@linux.intel.com> References: <20221109164913.909323-1-andi.shyti@linux.intel.com> MIME-Version: 1.0 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: , Cc: Andi Shyti , Tvrtko Ursulin , Chris Wilson , Matthew Auld , Andi Shyti , Tejas Upadhyay Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 +--------------------- drivers/gpu/drm/i915/i915_vma.c | 9 ++++++++ 3 files changed, 23 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 b684a62bf3b07..fcc77f120675f 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c @@ -16,6 +16,8 @@ #include "i915_gem_lmem.h" #include "i915_gem_mman.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) { return !(obj->cache_level == I915_CACHE_NONE || @@ -401,6 +403,17 @@ 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 717135f5bf5a6..531aca161295c 100644 --- a/drivers/gpu/drm/i915/gt/intel_ggtt.c +++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c @@ -347,27 +347,6 @@ 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) { /* @@ -953,8 +932,6 @@ 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; @@ -1102,7 +1079,7 @@ static int gen6_gmch_probe(struct i915_ggtt *ggtt) ggtt->vm.alloc_pt_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; diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index bf0f8d7e13405..f76c2d2fd3e75 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -562,6 +562,10 @@ bool i915_vma_misplaced(const struct i915_vma *vma, i915_vma_offset(vma) != (flags & PIN_OFFSET_MASK)) return true; + if (flags & PIN_OFFSET_GUARD && + vma->guard < (flags & PIN_OFFSET_MASK)) + return true; + return false; } @@ -639,6 +643,7 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags) GEM_BUG_ON(i915_vma_is_bound(vma, I915_VMA_GLOBAL_BIND | I915_VMA_LOCAL_BIND)); GEM_BUG_ON(drm_mm_node_allocated(&vma->node)); + GEM_BUG_ON(hweight64(flags & (PIN_OFFSET_GUARD | PIN_OFFSET_FIXED | PIN_OFFSET_BIAS)) > 1); size = max(size, vma->size); alignment = max_t(typeof(alignment), alignment, vma->display_alignment); @@ -653,6 +658,10 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags) GEM_BUG_ON(!is_power_of_2(alignment)); guard = vma->guard; /* retain guard across rebinds */ + if (flags & PIN_OFFSET_GUARD) { + GEM_BUG_ON(overflows_type(flags & PIN_OFFSET_MASK, u32)); + guard = max_t(u32, guard, flags & PIN_OFFSET_MASK); + } guard = ALIGN(guard, alignment); start = flags & PIN_OFFSET_BIAS ? flags & PIN_OFFSET_MASK : 0;