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 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 CB2BAD6D232 for ; Thu, 18 Dec 2025 16:22:36 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8A26610EA55; Thu, 18 Dec 2025 16:22:36 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="ZqC6xQtG"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.13]) by gabe.freedesktop.org (Postfix) with ESMTPS id DD7E510EA52; Thu, 18 Dec 2025 16:22:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1766074954; x=1797610954; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=TUIqmtGaiHh+Z57rwOAepUR3FSiiK+PppzEp3bJvC/M=; b=ZqC6xQtGrU10OSdNyHcRePIQmWejSABwRgZx6RcAIl88BL3aO6E4RHIC QBYhrCOmI3MP28RBadqvx+Gn49kR9H/oQw8ias2/NOfeZzOZBYBIyQQ2s dkF9Yjnx0+HBMWnqbFhmTk3dxtlzktUjkO3T1d9HrRP+6S7AQsCBhqYYE 1XaKd+02Oynn21gEhkvZlPbItWif4JxJAYSETqTm6vg0rHTt4BaW53Pls NyjhWJjVrGjUOFGv57mcS5KvmvOlCnUWUz/Vtx8jtuYx51GvsJFaQ51Nf rKe2epfMuS2L9BlP/BzuI84Kw4PjGPzB/VrFWfFkLlCSedkuSobas3VGl A==; X-CSE-ConnectionGUID: qBQmZo60TG+k8quWNvg8mQ== X-CSE-MsgGUID: n8zFepg/Tm+l3vlJwSwKLw== X-IronPort-AV: E=McAfee;i="6800,10657,11646"; a="70607684" X-IronPort-AV: E=Sophos;i="6.21,158,1763452800"; d="scan'208";a="70607684" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by fmvoesa107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Dec 2025 08:22:34 -0800 X-CSE-ConnectionGUID: qLVAm3WhRqid6qrsijFCCw== X-CSE-MsgGUID: /mqzTBwnTVygHejcEiX7NQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,158,1763452800"; d="scan'208";a="203705756" Received: from dhhellew-desk2.ger.corp.intel.com (HELO fedora) ([10.245.244.93]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Dec 2025 08:22:31 -0800 From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= To: intel-xe@lists.freedesktop.org Cc: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , Matthew Brost , dri-devel@lists.freedesktop.org, himal.prasad.ghimiray@intel.com, apopple@nvidia.com, airlied@gmail.com, Simona Vetter , felix.kuehling@amd.com, =?UTF-8?q?Christian=20K=C3=B6nig?= , dakr@kernel.org, "Mrozek, Michal" , Joonas Lahtinen Subject: [PATCH v5 16/24] drm/xe: Support pcie p2p dma as a fast interconnect Date: Thu, 18 Dec 2025 17:20:53 +0100 Message-ID: <20251218162101.605379-17-thomas.hellstrom@linux.intel.com> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251218162101.605379-1-thomas.hellstrom@linux.intel.com> References: <20251218162101.605379-1-thomas.hellstrom@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" Mimic the dma-buf method using dma_[map|unmap]_resource to map for pcie-p2p dma. There's an ongoing area of work upstream to sort out how this best should be done. One method proposed is to add an additional pci_p2p_dma_pagemap aliasing the device_private pagemap and use the corresponding pci_p2p_dma_pagemap page as input for dma_map_page(). However, that would incur double the amount of memory and latency to set up the drm_pagemap and given the huge amount of memory present on modern GPUs, that would really not work. Hence the simple approach used in this patch. v2: - Simplify xe_page_to_pcie(). (Matt Brost) Signed-off-by: Thomas Hellström Reviewed-by: Matthew Brost --- drivers/gpu/drm/xe/xe_svm.c | 34 +++++++++++++++++++++++++++++++--- drivers/gpu/drm/xe/xe_svm.h | 1 + 2 files changed, 32 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c index 4c2a850b80e2..c46ced7a9d64 100644 --- a/drivers/gpu/drm/xe/xe_svm.c +++ b/drivers/gpu/drm/xe/xe_svm.c @@ -3,6 +3,8 @@ * Copyright © 2024 Intel Corporation */ +#include + #include #include #include @@ -441,6 +443,14 @@ static u64 xe_page_to_dpa(struct page *page) return dpa; } +static u64 xe_page_to_pcie(struct page *page) +{ + struct xe_pagemap *xpagemap = xe_page_to_pagemap(page); + struct xe_vram_region *vr = xe_pagemap_to_vr(xpagemap); + + return xe_page_to_dpa(page) - vr->dpa_base + vr->io_start; +} + enum xe_svm_copy_dir { XE_SVM_COPY_TO_VRAM, XE_SVM_COPY_TO_SRAM, @@ -826,7 +836,10 @@ static bool xe_has_interconnect(struct drm_pagemap_peer *peer1, struct device *dev1 = xe_peer_to_dev(peer1); struct device *dev2 = xe_peer_to_dev(peer2); - return dev1 == dev2; + if (dev1 == dev2) + return true; + + return pci_p2pdma_distance(to_pci_dev(dev1), dev2, true) >= 0; } static DRM_PAGEMAP_OWNER_LIST_DEFINE(xe_owner_list); @@ -1599,13 +1612,27 @@ xe_drm_pagemap_device_map(struct drm_pagemap *dpagemap, addr = xe_page_to_dpa(page); prot = XE_INTERCONNECT_VRAM; } else { - addr = DMA_MAPPING_ERROR; - prot = 0; + addr = dma_map_resource(dev, + xe_page_to_pcie(page), + PAGE_SIZE << order, dir, + DMA_ATTR_SKIP_CPU_SYNC); + prot = XE_INTERCONNECT_P2P; } return drm_pagemap_addr_encode(addr, prot, order, dir); } +static void xe_drm_pagemap_device_unmap(struct drm_pagemap *dpagemap, + struct device *dev, + struct drm_pagemap_addr addr) +{ + if (addr.proto != XE_INTERCONNECT_P2P) + return; + + dma_unmap_resource(dev, addr.addr, PAGE_SIZE << addr.order, + addr.dir, DMA_ATTR_SKIP_CPU_SYNC); +} + static void xe_pagemap_destroy_work(struct work_struct *work) { struct xe_pagemap *xpagemap = container_of(work, typeof(*xpagemap), destroy_work); @@ -1642,6 +1669,7 @@ static void xe_pagemap_destroy(struct drm_pagemap *dpagemap, bool from_atomic_or static const struct drm_pagemap_ops xe_drm_pagemap_ops = { .device_map = xe_drm_pagemap_device_map, + .device_unmap = xe_drm_pagemap_device_unmap, .populate_mm = xe_drm_pagemap_populate_mm, .destroy = xe_pagemap_destroy, }; diff --git a/drivers/gpu/drm/xe/xe_svm.h b/drivers/gpu/drm/xe/xe_svm.h index ec7c6751cc86..50e80bc892b6 100644 --- a/drivers/gpu/drm/xe/xe_svm.h +++ b/drivers/gpu/drm/xe/xe_svm.h @@ -13,6 +13,7 @@ #include #define XE_INTERCONNECT_VRAM DRM_INTERCONNECT_DRIVER +#define XE_INTERCONNECT_P2P (XE_INTERCONNECT_VRAM + 1) struct drm_device; struct drm_file; -- 2.51.1