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 69332D111A8 for ; Mon, 1 Dec 2025 05:54:01 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2EA6D10E2A3; Mon, 1 Dec 2025 05:54:01 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="UJqAfmDz"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) by gabe.freedesktop.org (Postfix) with ESMTPS id 58F1110E2AA for ; Mon, 1 Dec 2025 05:53:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1764568439; x=1796104439; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=8UYsixHJCDbFPvZEb0rXTzIvgu77AOyO3EKbuVMn57U=; b=UJqAfmDzV+fXNBDmgRqq1EUoOsK49QSsm5tUJ1aR8b+ul+YWIluv2N4d 1QQibjQLQjuGD+8fcFhUkoGf8AoHEjxF+OaXDZcogrW/0HywrH/e0a/PM R1nkQKUtFbYUYkXPvhjlHwrEF66Bplx9f8icsDHO+wENwr4Fb22TG1awD Nvofuz5akigpftOkRRasOLJY917qQmQ3dbWUoNXxJlqs7QN240OSoVAXm rGTtrwMmIdi+euW7Jyc8QlmIKgKhtzQiOE1Z6Bi9yIUCp66Z1KhjY4NOj Q73ek1bRXjqGe9NAJrGg3YcgnWj9bpqNKnmzDVs5Qv7erG8cbRKdicrbJ w==; X-CSE-ConnectionGUID: HR3a+uVUQBO3/3DmRShiSg== X-CSE-MsgGUID: 6K/BNBTVTO6BSjAwd9QPAQ== X-IronPort-AV: E=McAfee;i="6800,10657,11629"; a="66457392" X-IronPort-AV: E=Sophos;i="6.20,240,1758610800"; d="scan'208";a="66457392" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Nov 2025 21:53:59 -0800 X-CSE-ConnectionGUID: eIzKx8TvSCGr2PnUz16ByQ== X-CSE-MsgGUID: B79HEVNWTUCY/Us9QGNUMg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.20,240,1758610800"; d="scan'208";a="224950839" Received: from varungup-desk.iind.intel.com ([10.190.238.71]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Nov 2025 21:53:57 -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 v2 7/9] drm/xe/vm: Prevent binding of purged buffer objects Date: Mon, 1 Dec 2025 11:20:17 +0530 Message-ID: <20251201055309.854074-8-arvind.yadav@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251201055309.854074-1-arvind.yadav@intel.com> References: <20251201055309.854074-1-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" Add validation in xe_vm_bind_ioctl_validate_bo() to reject MAP and PREFETCH operations on purged buffer objects with -EINVAL. Problem: When a BO is purged (XE_MADV_PURGEABLE_PURGED state), its backing pages have been freed by the kernel. Without this check, VM_BIND operations would proceed: 1. DRM_XE_VM_BIND_OP_MAP: Attempts to create GPU mappings to freed memory - xe_vma_ops_alloc() creates VMA pointing to invalid BO - Page tables populated with stale/invalid addresses - GPU access leads to undefined behavior or hangs 2. DRM_XE_VM_BIND_OP_PREFETCH: Attempts to migrate non-existent pages - Triggers BO validation in TTM - ttm_bo_validate() fails or crashes (no backing store) - Wasted work for permanently invalid BO With this check: - MAP/PREFETCH immediately fail with -EINVAL at ioctl boundary - Clear error message at syscall (better UX than deferred GPU hang) - Prevents creation of invalid GPU page table entries v2: - Clarify that purged BOs are permanently invalid (i915 semantics) - Remove incorrect claim about madvise(WILLNEED) restoring purged BOs Cc: Matthew Brost Cc: Thomas Hellström Cc: Himal Prasad Ghimiray Signed-off-by: Arvind Yadav --- drivers/gpu/drm/xe/xe_vm.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c index d03e69524369..cc946bff9607 100644 --- a/drivers/gpu/drm/xe/xe_vm.c +++ b/drivers/gpu/drm/xe/xe_vm.c @@ -3482,6 +3482,13 @@ static int xe_vm_bind_ioctl_validate_bo(struct xe_device *xe, struct xe_bo *bo, return -EINVAL; } + /* Purged BOs are permanently invalid; reject new MAP/PREFETCH. */ + if (XE_IOCTL_DBG(xe, + xe_bo_is_purged(bo) && + (op == DRM_XE_VM_BIND_OP_MAP || + op == DRM_XE_VM_BIND_OP_PREFETCH))) + return -EINVAL; + /* * Some platforms require 64k VM_BIND alignment, * specifically those with XE_VRAM_FLAGS_NEED64K. -- 2.43.0