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 8F313E6BF3B for ; Fri, 30 Jan 2026 22:08:00 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 56FA810E12D; Fri, 30 Jan 2026 22:08:00 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="fuFO6BzM"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.9]) by gabe.freedesktop.org (Postfix) with ESMTPS id D982510E12D for ; Fri, 30 Jan 2026 22:07:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1769810880; x=1801346880; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Dg+h7Tev3AkPmB+X8QR61HHPpOAMika6IoT9ZBEYiNI=; b=fuFO6BzMsrTwqeJIejHk/SvGbTCn3xkmUNCm7uB6uZ52QiZBJwyAbUKV OVLlV4uz0OML62jdWCMOv01pid/R1kvd0EjmM4QxmNJRoZ4TXWcOkboVU 3xZ8tfjJbHXwqhZ8BIYqKpP/XS7RPOOyeW9W29lmM1KiJhsr+V5ZE7lmK NTYukm98sbfL4c+qrMXakAhOvBbNBPei6rgTi7cUcwZ/kSvXM2v6hntSQ 9kSJ7aXvAAPx4lNc+tLonBTVbVbL4G+vobhIm+WnNa8MKifLk8HUKSKT+ 4kvjX7EwaNZWeedIW9iCFj6OcWTMSvGo5KLS93/v155ClrW08xwdPFeQr w==; X-CSE-ConnectionGUID: eojpANNNQJqIp1xQFjtWSQ== X-CSE-MsgGUID: Zhhf9bVMSxSlOMs3oEfGmQ== X-IronPort-AV: E=McAfee;i="6800,10657,11687"; a="81800204" X-IronPort-AV: E=Sophos;i="6.21,263,1763452800"; d="scan'208";a="81800204" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Jan 2026 14:08:00 -0800 X-CSE-ConnectionGUID: DionjiCNSe2Jtsk607jDBw== X-CSE-MsgGUID: OBuSjlPCRnGavi+Z2H5EJw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,263,1763452800"; d="scan'208";a="213459060" Received: from dut6094bmgfrd.fm.intel.com ([10.80.55.45]) by fmviesa005.fm.intel.com with ESMTP; 30 Jan 2026 14:07:59 -0800 From: Jia Yao To: intel-xe@lists.freedesktop.org Cc: Jia Yao , stable@vger.kernel.org, Mathew Alwin , Michal Mrozek , Matthew Brost , Matthew Auld Subject: [PATCH v3] drm/xe/uapi: Reject coh_none PAT index for CPU cached memory in madvise Date: Fri, 30 Jan 2026 22:07:49 +0000 Message-ID: <20260130220750.573838-1-jia.yao@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260129000147.339361-1-jia.yao@intel.com> References: <20260129000147.339361-1-jia.yao@intel.com> MIME-Version: 1.0 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" Add validation in xe_vm_madvise_ioctl() to reject PAT indices with XE_COH_NONE coherency mode when applied to CPU cached memory. Using coh_none with CPU cached buffers is a security issue. When the kernel clears pages before reallocation, the clear operation stays in CPU cache (dirty). GPU with coh_none can bypass CPU caches and read stale sensitive data directly from DRAM, potentially leaking data from previously freed pages of other processes. This aligns with the existing validation in vm_bind path (xe_vm_bind_ioctl_validate_bo). v2(Matthew brost) - Add fixes - Move one debug print to better place v3(Matthew Auld) - Should be drm/xe/uapi - More Cc Fixes: ada7486c5668 ("drm/xe: Implement madvise ioctl for xe") Cc: stable@vger.kernel.org # v6.18 Cc: Mathew Alwin Cc: Michal Mrozek Cc: Matthew Brost Cc: Matthew Auld Signed-off-by: Jia Yao --- drivers/gpu/drm/xe/xe_vm_madvise.c | 47 ++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/drivers/gpu/drm/xe/xe_vm_madvise.c b/drivers/gpu/drm/xe/xe_vm_madvise.c index add9a6ca2390..50b82e821da7 100644 --- a/drivers/gpu/drm/xe/xe_vm_madvise.c +++ b/drivers/gpu/drm/xe/xe_vm_madvise.c @@ -352,6 +352,44 @@ static void xe_madvise_details_fini(struct xe_madvise_details *details) drm_pagemap_put(details->dpagemap); } +static bool check_pat_args_are_sane(struct xe_device *xe, + struct xe_vmas_in_madvise_range *madvise_range, + u16 pat_index) +{ + u16 coh_mode = xe_pat_index_get_coh_mode(xe, pat_index); + int i; + + /* + * Using coh_none with CPU cached buffers is not allowed. + * Otherwise CPU page clearing can be bypassed, which is a + * security issue. GPU can directly access system memory and + * bypass CPU caches, potentially reading stale sensitive data + * from previously freed pages. + */ + if (coh_mode != XE_COH_NONE) + return true; + + for (i = 0; i < madvise_range->num_vmas; i++) { + struct xe_vma *vma = madvise_range->vmas[i]; + struct xe_bo *bo = xe_vma_bo(vma); + + if (bo) { + /* BO with WB caching + COH_NONE is not allowed */ + if (XE_IOCTL_DBG(xe, bo->cpu_caching == DRM_XE_GEM_CPU_CACHING_WB)) + return false; + /* Imported dma-buf without caching info, assume cached */ + if (XE_IOCTL_DBG(xe, !bo->cpu_caching)) + return false; + } else if (XE_IOCTL_DBG(xe, xe_vma_is_cpu_addr_mirror(vma)) || + xe_vma_is_userptr(vma)) { + /* System memory (userptr/SVM) is always CPU cached */ + return false; + } + } + + return true; +} + static bool check_bo_args_are_sane(struct xe_vm *vm, struct xe_vma **vmas, int num_vmas, u32 atomic_val) { @@ -442,6 +480,14 @@ int xe_vm_madvise_ioctl(struct drm_device *dev, void *data, struct drm_file *fil if (err || !madvise_range.num_vmas) goto madv_fini; + if (args->type == DRM_XE_MEM_RANGE_ATTR_PAT) { + if (!check_pat_args_are_sane(xe, &madvise_range, + args->pat_index.val)) { + err = -EINVAL; + goto free_vmas; + } + } + if (madvise_range.has_bo_vmas) { if (args->type == DRM_XE_MEM_RANGE_ATTR_ATOMIC) { if (!check_bo_args_are_sane(vm, madvise_range.vmas, @@ -485,6 +531,7 @@ int xe_vm_madvise_ioctl(struct drm_device *dev, void *data, struct drm_file *fil err_fini: if (madvise_range.has_bo_vmas) drm_exec_fini(&exec); +free_vmas: kfree(madvise_range.vmas); madvise_range.vmas = NULL; madv_fini: -- 2.43.0