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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5486C433F5 for ; Wed, 27 Apr 2022 17:56:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229451AbiD0R72 (ORCPT ); Wed, 27 Apr 2022 13:59:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49066 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244508AbiD0R71 (ORCPT ); Wed, 27 Apr 2022 13:59:27 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9486E2FC89A; Wed, 27 Apr 2022 10:56:15 -0700 (PDT) Received: from fraeml743-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4KpRCZ106zz67gQT; Thu, 28 Apr 2022 01:52:10 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml743-chm.china.huawei.com (10.206.15.224) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 27 Apr 2022 19:56:13 +0200 Received: from localhost (10.81.200.74) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2375.24; Wed, 27 Apr 2022 18:56:12 +0100 Date: Wed, 27 Apr 2022 18:56:10 +0100 From: Jonathan Cameron To: CC: Dan Williams , Bjorn Helgaas , Alison Schofield , "Vishal Verma" , Ben Widawsky , , , Subject: Re: [PATCH V8 08/10] cxl/cdat: Introduce cxl_cdat_valid() Message-ID: <20220427185610.0000201a@Huawei.com> In-Reply-To: <20220414203237.2198665-9-ira.weiny@intel.com> References: <20220414203237.2198665-1-ira.weiny@intel.com> <20220414203237.2198665-9-ira.weiny@intel.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.29; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.81.200.74] X-ClientProxiedBy: lhreml709-chm.china.huawei.com (10.201.108.58) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, 14 Apr 2022 13:32:35 -0700 ira.weiny@intel.com wrote: > From: Ira Weiny > > The CDAT data is protected by a checksum and should be the proper > length. > > Introduce cxl_cdat_valid() to validate the data. While at it check and > store the sequence number. > > Signed-off-by: Ira Weiny > Reviewed-by: Jonathan Cameron > --- > Changes from V6 > Change name to cxl_cdat_valid() as this validates all the CDAT > data not just the header > Add error and debug prints > > Changes from V5 > New patch, split out > Update cdat_hdr_valid() > Remove revision and cs field parsing > There is no point in these > Add seq check and debug print. > --- > drivers/cxl/cdat.h | 2 ++ > drivers/cxl/pci.c | 36 ++++++++++++++++++++++++++++++++++++ > 2 files changed, 38 insertions(+) > > diff --git a/drivers/cxl/cdat.h b/drivers/cxl/cdat.h > index 4722b6bbbaf0..a7725d26f2d2 100644 > --- a/drivers/cxl/cdat.h > +++ b/drivers/cxl/cdat.h > @@ -88,10 +88,12 @@ > * > * @table: cache of CDAT table > * @length: length of cached CDAT table > + * @seq: Last read Sequence number of the CDAT table > */ > struct cxl_cdat { > void *table; > size_t length; > + u32 seq; > }; > > #endif /* !__CXL_CDAT_H__ */ > diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c > index aecb327911a0..d7952156dd02 100644 > --- a/drivers/cxl/pci.c > +++ b/drivers/cxl/pci.c > @@ -781,6 +781,40 @@ static int cxl_setup_doe_devices(struct cxl_dev_state *cxlds) > return 0; > } > > +static bool cxl_cdat_valid(struct device *dev, struct cxl_cdat *cdat) > +{ > + u32 *table = cdat->table; > + u8 *data8 = cdat->table; > + u32 length, seq; > + u8 check; > + int i; > + > + length = FIELD_GET(CDAT_HEADER_DW0_LENGTH, table[0]); > + if ((length < CDAT_HEADER_LENGTH_BYTES) || (length > cdat->length)) { > + dev_err(dev, "Invalid length %u (%lu-%lu)\n", length, > + CDAT_HEADER_LENGTH_BYTES, cdat->length); > + return false; > + } > + > + for (check = 0, i = 0; i < length; i++) > + check += data8[i]; > + > + dev_dbg(dev, "CDAT length %u CS %u\n", length, check); > + if (check != 0) { > + dev_err(dev, "Invalid checksum %u\n", check); > + return false; > + } > + > + seq = FIELD_GET(CDAT_HEADER_DW3_SEQUENCE, table[3]); > + /* Store the sequence for now. */ > + if (cdat->seq != seq) { > + dev_info(dev, "CDAT seq change %x -> %x\n", cdat->seq, seq); > + cdat->seq = seq; > + } > + > + return true; > +} > + > #define CDAT_DOE_REQ(entry_handle) \ > (FIELD_PREP(CXL_DOE_TABLE_ACCESS_REQ_CODE, \ > CXL_DOE_TABLE_ACCESS_REQ_CODE_READ) | \ > @@ -892,6 +926,8 @@ static int cxl_cdat_read_table(struct cxl_dev_state *cxlds, > > release_driver: > cxl_pci_doe_put_drv(doe_dev); > + if (!rc && !cxl_cdat_valid(cxlds->dev, cdat)) > + return -EIO; > return rc; > } >