From patchwork Mon Apr 2 08:34:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Zhang, Xiong Y" X-Patchwork-Id: 10319477 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 05D0260467 for ; Mon, 2 Apr 2018 08:35:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E511E28BAC for ; Mon, 2 Apr 2018 08:35:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D985528C03; Mon, 2 Apr 2018 08:35:48 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id C609828BAC for ; Mon, 2 Apr 2018 08:35:46 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E90936E07F; Mon, 2 Apr 2018 08:35:44 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id AB07E6E07F; Mon, 2 Apr 2018 08:35:43 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Apr 2018 01:35:42 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,394,1517904000"; d="scan'208";a="40025051" Received: from test-optiplex-7040.bj.intel.com ([10.238.154.174]) by orsmga003.jf.intel.com with ESMTP; 02 Apr 2018 01:35:32 -0700 From: Xiong Zhang To: intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Date: Mon, 2 Apr 2018 16:34:21 +0800 Message-Id: <1522658062-3201-1-git-send-email-xiong.y.zhang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <152231205673.10679.7263510846193056616@mail.alporthouse.com> References: <152231205673.10679.7263510846193056616@mail.alporthouse.com> Subject: [Intel-gfx] [PATCH v2] drm/i915: Don't deballoon unused ggtt drm_mm_node in linux guest X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Virus-Scanned: ClamAV using ClamSMTP The following call trace may exist in linux guest dmesg when guest i915 driver is unloaded. [ 90.776610] [drm:vgt_deballoon_space.isra.0 [i915]] deballoon space: range [0x0 - 0x0] 0 KiB. [ 90.776621] BUG: unable to handle kernel NULL pointer dereference at 00000000000000c0 [ 90.776691] IP: drm_mm_remove_node+0x4d/0x320 [drm] [ 90.776718] PGD 800000012c7d0067 P4D 800000012c7d0067 PUD 138e4c067 PMD 0 [ 90.777091] task: ffff9adab60f2f00 task.stack: ffffaf39c0fe0000 [ 90.777142] RIP: 0010:drm_mm_remove_node+0x4d/0x320 [drm] [ 90.777573] Call Trace: [ 90.777653] intel_vgt_deballoon+0x4c/0x60 [i915] [ 90.777729] i915_ggtt_cleanup_hw+0x121/0x190 [i915] [ 90.777792] i915_driver_unload+0x145/0x180 [i915] [ 90.777856] i915_pci_remove+0x15/0x20 [i915] [ 90.777890] pci_device_remove+0x3b/0xc0 [ 90.777916] device_release_driver_internal+0x157/0x220 [ 90.777945] driver_detach+0x39/0x70 [ 90.777967] bus_remove_driver+0x51/0xd0 [ 90.777990] pci_unregister_driver+0x23/0x90 [ 90.778019] SyS_delete_module+0x1da/0x240 [ 90.778045] entry_SYSCALL_64_fastpath+0x24/0x87 [ 90.778072] RIP: 0033:0x7f34312af067 [ 90.778092] RSP: 002b:00007ffdea3da0d8 EFLAGS: 00000206 [ 90.778297] RIP: drm_mm_remove_node+0x4d/0x320 [drm] RSP: ffffaf39c0fe3dc0 [ 90.778344] ---[ end trace f4b1bc8305fc59dd ]--- Four drm_mm_node are used to reserve guest ggtt space, but some of them may be skipped and not initialised due to space constraints in intel_vgt_balloon(). If drm_mm_remove_node() is called with uninitialized drm_mm_node, the above call trace occurs. This patch check drm_mm_node's validity before calling drm_mm_remove_node(). v2: Make commit message clear (Chris) Fixes: ff8f797557c7("drm/i915: return the correct usable aperture size under gvt environment") Signed-off-by: Xiong Zhang Reviewed-by: Chris Wilson --- drivers/gpu/drm/i915/i915_vgpu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_vgpu.c b/drivers/gpu/drm/i915/i915_vgpu.c index 5fe9f3f..7545686 100644 --- a/drivers/gpu/drm/i915/i915_vgpu.c +++ b/drivers/gpu/drm/i915/i915_vgpu.c @@ -100,6 +100,9 @@ static struct _balloon_info_ bl_info; static void vgt_deballoon_space(struct i915_ggtt *ggtt, struct drm_mm_node *node) { + if (!node->allocated) + return; + DRM_DEBUG_DRIVER("deballoon space: range [0x%llx - 0x%llx] %llu KiB.\n", node->start, node->start + node->size,