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 13259C021B8 for ; Wed, 26 Feb 2025 17:48:34 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8749010E985; Wed, 26 Feb 2025 17:48:34 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="TBD3NfTe"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) by gabe.freedesktop.org (Postfix) with ESMTPS id BACD510E985 for ; Wed, 26 Feb 2025 17:48:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1740592114; x=1772128114; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=utwP7sgrc/mPnToD/YRZ2ym51BUM5uJh8Ub8FCA++1Y=; b=TBD3NfTe8yPnhllrnCkPpgUS5yYG5fI8IM5TFIJuB7N2r6mPQdxb7Pxq fNEPHizKOB2Q6HsP+T7uUd79vyzxBTMfQmBu3hAGdLVc9e0v2JdxrzuJd GM3uCf4cekVK+kJu8nvvZN1g/JXgFx6ze1yKlDZc7jo33H/I47zcz0rQY Lnz3g+avkg9qmFN7V1SJJXu9NWeJP+NKT5jdBgAlsItyZI/JSkW/P5ncW teYXsLgM6ERqjSXqBdJNUiZ999QsDlxWyym7k2Rg/dZMgxuvLfYQI//7B QrSoGxXkIx7vKnoFXxpZVxte8PwIOT5y1mjdP10wjZ4Rrfnl5Pbxh7XCz g==; X-CSE-ConnectionGUID: FZlw54U2Q2KEVpaD0lwIEw== X-CSE-MsgGUID: RY4tgiETRpygOakb/QLY5w== X-IronPort-AV: E=McAfee;i="6700,10204,11357"; a="52852784" X-IronPort-AV: E=Sophos;i="6.13,317,1732608000"; d="scan'208";a="52852784" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Feb 2025 09:48:33 -0800 X-CSE-ConnectionGUID: tgX7Db6KRBSxEFxu8U08zg== X-CSE-MsgGUID: zn2jJ2oYTNC2PFNOYu3X4Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.13,317,1732608000"; d="scan'208";a="121715666" Received: from mjarzebo-mobl1.ger.corp.intel.com (HELO mwauld-desk.intel.com) ([10.245.245.27]) by ORVIESA003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Feb 2025 09:48:31 -0800 From: Matthew Auld To: intel-xe@lists.freedesktop.org Cc: Matthew Brost , =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= , stable@vger.kernel.org Subject: [PATCH v2] drm/xe/userptr: properly setup pfn_flags_mask Date: Wed, 26 Feb 2025 17:47:49 +0000 Message-ID: <20250226174748.294285-2-matthew.auld@intel.com> X-Mailer: git-send-email 2.48.1 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" Currently we just leave it uninitialised, which at first looks harmless, however we also don't zero out the pfn array, and with pfn_flags_mask the idea is to be able set individual flags for a given range of pfn or completely ignore them, outside of default_flags. So here we end up with pfn[i] & pfn_flags_mask, and if both are uninitialised we might get back an unexpected flags value, like asking for read only with default_flags, but getting back write on top, leading to potentially bogus behaviour. To fix this ensure we zero the pfn_flags_mask, such that hmm only considers the default_flags and not also the initial pfn[i] value. v2 (Thomas): - Prefer proper initializer. Fixes: 81e058a3e7fd ("drm/xe: Introduce helper to populate userptr") Signed-off-by: Matthew Auld Cc: Matthew Brost Cc: Thomas Hellström Cc: # v6.10+ --- drivers/gpu/drm/xe/xe_hmm.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_hmm.c b/drivers/gpu/drm/xe/xe_hmm.c index 089834467880..2e4ae61567d8 100644 --- a/drivers/gpu/drm/xe/xe_hmm.c +++ b/drivers/gpu/drm/xe/xe_hmm.c @@ -166,13 +166,20 @@ int xe_hmm_userptr_populate_range(struct xe_userptr_vma *uvma, { unsigned long timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); - unsigned long *pfns, flags = HMM_PFN_REQ_FAULT; + unsigned long *pfns; struct xe_userptr *userptr; struct xe_vma *vma = &uvma->vma; u64 userptr_start = xe_vma_userptr(vma); u64 userptr_end = userptr_start + xe_vma_size(vma); struct xe_vm *vm = xe_vma_vm(vma); - struct hmm_range hmm_range; + struct hmm_range hmm_range = { + .pfn_flags_mask = 0, /* ignore pfns */ + .default_flags = HMM_PFN_REQ_FAULT, + .start = userptr_start, + .end = userptr_end, + .notifier = &uvma->userptr.notifier, + .dev_private_owner = vm->xe, + }; bool write = !xe_vma_read_only(vma); unsigned long notifier_seq; u64 npages; @@ -199,19 +206,14 @@ int xe_hmm_userptr_populate_range(struct xe_userptr_vma *uvma, return -ENOMEM; if (write) - flags |= HMM_PFN_REQ_WRITE; + hmm_range.default_flags |= HMM_PFN_REQ_WRITE; if (!mmget_not_zero(userptr->notifier.mm)) { ret = -EFAULT; goto free_pfns; } - hmm_range.default_flags = flags; hmm_range.hmm_pfns = pfns; - hmm_range.notifier = &userptr->notifier; - hmm_range.start = userptr_start; - hmm_range.end = userptr_end; - hmm_range.dev_private_owner = vm->xe; while (true) { hmm_range.notifier_seq = mmu_interval_read_begin(&userptr->notifier); -- 2.48.1