Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751989AbdI2Fih (ORCPT ); Fri, 29 Sep 2017 01:38:37 -0400 Received: from stargate.chelsio.com ([12.32.117.8]:34556 "EHLO stargate.chelsio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750996AbdI2Fif (ORCPT ); Fri, 29 Sep 2017 01:38:35 -0400 Subject: Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU To: "Raj, Ashok" Cc: Casey Leedom , Robin Murphy , Dan Williams , Herbert Xu , "linux-kernel@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "linux-crypto@vger.kernel.org" , "dwmw2@infradead.org" , Michael Werner , "nd@arm.com" References: <6d2af675-7b97-6eaf-4daa-d7bf80a05923@chelsio.com> <437a9bd8-d4d6-22ca-1a64-1a3e73f1101a@arm.com> <20170927181802.3dcd7efb@m750.lan> <20170927144847.GA95654@otc-nc-03> <26d68681-a157-26d3-84cb-6684dcaf3135@chelsio.com> <20170928130549.GA99456@otc-nc-03> From: Harsh Jain Message-ID: Date: Fri, 29 Sep 2017 11:07:36 +0530 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <20170928130549.GA99456@otc-nc-03> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1523 Lines: 29 On 28-09-2017 18:35, Raj, Ashok wrote: > Thanks for trying that Harsh. > > sp_off turns of super page support. Which this mode, do you still see offsets greater than 4k? Yes, offset greater than 4k is still there. Refer below. [56732.774872] offset 4110 len 76 dma addr 3a531200e dma len 76 [56732.804187] offset 4110 len 84 dma addr 3a63b200e dma len 84 [56732.805104] offset 4110 len 68 dma addr 3a531200e dma len 68 [56732.806870] offset 4110 len 56 dma addr 3a531200e dma len 56 [56732.808987] offset 4110 len 56 dma addr 3a531200e dma len 56 [56732.811215] offset 4110 len 56 dma addr 3a531200e dma len 56 [56732.813155] offset 4110 len 56 dma addr 3a531200e dma len 56 [56732.814823] offset 4110 len 56 dma addr 3a531200e dma len 56 [56732.816481] offset 4110 len 56 dma addr 3a531200e dma len 56 [56732.818159] offset 4110 len 56 dma addr 3a531200e dma len 56 [56732.819712] offset 4110 len 56 dma addr 3a531200e dma len 56 [56732.821629] offset 4110 len 56 dma addr 3a531200e dma len 56 [root@heptagon linux_t4_build]# [root@heptagon linux_t4_build]# [root@heptagon linux_t4_build]# cat /proc/cmdline BOOT_IMAGE=/vmlinuz-4.9.51 root=UUID=ccbb7f18-b3f0-43df-89de-07521e9c02fe ro intel_iommu=sp_off crashkernel=auto rhgb quiet rhgb quiet console=ttyS0,115200, console=tty0 LANG=en_US.UTF-8 > > On Thu, Sep 28, 2017 at 07:08:21PM +0530, Harsh Jain wrote: >> >> Today I tried with "Intel_iommu=sp_off" boot option. Traffic runs without any error for more than 1 hrs. What magic this option did? :) > Cheers, > Ashok