From: Casey Leedom Subject: Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU Date: Wed, 27 Sep 2017 22:13:04 +0000 Message-ID: References: <6d2af675-7b97-6eaf-4daa-d7bf80a05923@chelsio.com> <437a9bd8-d4d6-22ca-1a64-1a3e73f1101a@arm.com> <20170927181802.3dcd7efb@m750.lan> <20170927144847.GA95654@otc-nc-03> ,<20170927190745.GA96373@otc-nc-03> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Cc: Robin Murphy , Dan Williams , "Harsh Jain" , 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" To: "Raj, Ashok" Return-path: Received: from mail-by2nam03on0094.outbound.protection.outlook.com ([104.47.42.94]:44096 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752095AbdI0WNK (ORCPT ); Wed, 27 Sep 2017 18:13:10 -0400 In-Reply-To: <20170927190745.GA96373@otc-nc-03> Content-Language: en-US Sender: linux-crypto-owner@vger.kernel.org List-ID: | From: Raj, Ashok | Sent: Wednesday, September 27, 2017 12:07 PM | | looking at the debug output i got from Harsh it still looks like a bug in | the code. | | [ 538.284589] __domain_mapping nr_pages 0x1 | [ 538.284600] __domain_mapping sg_res 0x1 sg->dma_address 0xf291000e dma = len | 0x38 pteval 0x3cbce3003 phys_pfn 0x3cbce3 | [ 538.284604] chelsio driver - offset 4110 len 56 dma addr f291000e dma l= en | 56 | [ 538.284667] DMAR: DRHD: handling fault status reg 2 | [ 538.290017] DMAR: [DMA Write] Request device [02:00.4] fault addr f2910= 000 | [fault reason 05] PTE Write access is not set | | somehow when crypto_authenc_encrypt() -> scatterwalk_ffwd()-> sg_set_page= () | | ->sg_set_page(dst, sg_page(src), src->length - len, src->offset + len); | | src->offset + len gets set as sg->offset in sg_set_page(). Either the | assumption that there should be room is incorrect, or some higher order | crypto | code that ends up setting the offset did the wrong calculation. | | if src->offset is already towards the end of the page, then offset+len wi= ll | go beyond the end of page. Hhmmm, it seems like we need Herbert to comment on this. Herbert, is there any specific debugging information that you'd like to see here? Casey