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 45F4AD3B9A9 for ; Wed, 10 Dec 2025 04:32:24 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D9F2410E65D; Wed, 10 Dec 2025 04:32:23 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="FN0fFbRd"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.9]) by gabe.freedesktop.org (Postfix) with ESMTPS id 563B410E65C for ; Wed, 10 Dec 2025 04:32:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1765341142; x=1796877142; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=51bznLstXSeTDtQtSJk3zK1yzNxRaTuuWy5nu6XWbBk=; b=FN0fFbRdUxJquj1wNLljjzpUt1OjdtWE/Wcc1e7vLzr3MlckxgxYNgYY EJsnjpnsKC3TYSj7ZDuT/11wUrxsDFEccY3L1E9nrQyhimQl4mBd57WEF 2GK/Ht+/TnJ2oBQG4pX+bPu1ck/+skOI5jmBYl+K1PD82wt+nq0pPfvdp dNmoTeTjnDKkydZhd1tzTi7u3OeOaIVc6C7ybR0XSvLy6o3/Ft6BxCx3n vc5Y3Q6fWU0/kqKJU/lBSf4mjwhfJgRA1S138DNDg72X6i3wlS+7uWm0y M8O1Ui1R5F34/scPcXqzgmSokwT5c4l+/AlpC7WdTurtq+48Z0OUH2Yrg Q==; X-CSE-ConnectionGUID: gC9QFc+4Smeaywp74aJL9g== X-CSE-MsgGUID: fO705KRYQJucwtzZ5I5c5g== X-IronPort-AV: E=McAfee;i="6800,10657,11637"; a="78000062" X-IronPort-AV: E=Sophos;i="6.20,263,1758610800"; d="scan'208";a="78000062" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Dec 2025 20:32:22 -0800 X-CSE-ConnectionGUID: 7mIYVoZfTmqFFn1Xtdx3bA== X-CSE-MsgGUID: BPq3WN4PQJKA2xayFWMBow== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.20,263,1758610800"; d="scan'208";a="196466663" Received: from varungup-desk.iind.intel.com ([10.190.238.71]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Dec 2025 20:32:21 -0800 From: Arvind Yadav To: intel-xe@lists.freedesktop.org Cc: matthew.brost@intel.com, himal.prasad.ghimiray@intel.com, thomas.hellstrom@linux.intel.com, pallavi.mishra@intel.com Subject: [RFC v3 4/8] drm/xe/bo: Handle CPU faults on purged buffer objects Date: Wed, 10 Dec 2025 10:00:48 +0530 Message-ID: <20251210043112.3267620-5-arvind.yadav@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251210043112.3267620-1-arvind.yadav@intel.com> References: <20251210043112.3267620-1-arvind.yadav@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" Return -EFAULT when CPU attempts to access a purged buffer object. Purged BOs have their backing store reclaimed by the kernel, making CPU access invalid. For mmap() users, this is reported as SIGBUS via the usual VM_FAULT_SIGBUS conversion, matching i915 semantics. Check xe_bo_is_purged() under dma-resv lock in the page fault handler to prevent races. The fault handler returns VM_FAULT_SIGBUS to signal the error to userspace. v2: - Added xe_bo_is_purged(bo) instead of atomic_read. - Avoids leaks and keeps drm_dev_exit() while returning. v3: - Move xe_bo_is_purged check under a dma-resv lock (Matthew Brost) Cc: Matthew Brost Cc: Thomas Hellström Cc: Himal Prasad Ghimiray Signed-off-by: Arvind Yadav --- drivers/gpu/drm/xe/xe_bo.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c index c161ac6420db..31b2fa490440 100644 --- a/drivers/gpu/drm/xe/xe_bo.c +++ b/drivers/gpu/drm/xe/xe_bo.c @@ -2033,6 +2033,12 @@ static vm_fault_t xe_bo_cpu_fault(struct vm_fault *vmf) if (err) break; + /* Purged BOs have no backing store - fault to userspace */ + if (xe_bo_is_purged(bo)) { + err = -EFAULT; + break; + } + if (xe_ttm_bo_is_imported(tbo)) { err = -EFAULT; drm_dbg(&xe->drm, "CPU trying to access an imported buffer object.\n"); -- 2.43.0