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 1D81CC433FE for ; Fri, 4 Feb 2022 13:33:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358860AbiBDNdM (ORCPT ); Fri, 4 Feb 2022 08:33:12 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:4674 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232599AbiBDNdK (ORCPT ); Fri, 4 Feb 2022 08:33:10 -0500 Received: from fraeml708-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4JqxG21Chnz67Zm5; Fri, 4 Feb 2022 21:29:14 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml708-chm.china.huawei.com (10.206.15.36) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Fri, 4 Feb 2022 14:33:07 +0100 Received: from localhost (10.47.31.86) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Fri, 4 Feb 2022 13:33:06 +0000 Date: Fri, 4 Feb 2022 13:33:03 +0000 From: Jonathan Cameron To: Ira Weiny CC: Ben Widawsky , Dan Williams , Bjorn Helgaas , "Alison Schofield" , Vishal Verma , , , Subject: Re: [PATCH V6 10/10] cxl/cdat: Parse out DSMAS data from CDAT table Message-ID: <20220204133303.0000667b@Huawei.com> In-Reply-To: <20220201223717.GR785175@iweiny-DESK2.sc.intel.com> References: <20220201071952.900068-1-ira.weiny@intel.com> <20220201071952.900068-11-ira.weiny@intel.com> <20220201190532.ynwr73ninobqx7bm@intel.com> <20220201223717.GR785175@iweiny-DESK2.sc.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: [10.47.31.86] X-ClientProxiedBy: lhreml724-chm.china.huawei.com (10.201.108.75) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 1 Feb 2022 14:37:17 -0800 Ira Weiny wrote: > On Tue, Feb 01, 2022 at 11:05:32AM -0800, Widawsky, Ben wrote: > > On 22-01-31 23:19:52, ira.weiny@intel.com wrote: > > > From: Ira Weiny > > > > > > CXL memory devices need the information in the Device Scoped Memory > > > Affinity Structure (DSMAS). This information is contained within the > > > CDAT table buffer which is already read and cached. > > > > > > Parse and cache DSMAS data from the CDAT table. Store this data in > > > unmarshaled struct dsmas data structures for ease of use. > > > > > > Signed-off-by: Ira Weiny > > > > > > --- > > > Changes from V5 > > > Fix up sparse warnings > > > Split out cdat_hdr_valid() > > > Update cdat_hdr_valid() > > > Remove revision and cs field parsing > > > There is no point in these > > > Add seq check and debug print. > > > From Jonathan > > > Add spaces around '+' and '/' > > > use devm_krealloc() for dmas_ary > > > > > > Changes from V4 > > > New patch > > > --- > > > drivers/cxl/cdat.h | 21 ++++++++++++ > > > drivers/cxl/core/memdev.c | 70 +++++++++++++++++++++++++++++++++++++++ > > > 2 files changed, 91 insertions(+) > > > > > > diff --git a/drivers/cxl/cdat.h b/drivers/cxl/cdat.h > > > index a7725d26f2d2..f8c126190d18 100644 > > > --- a/drivers/cxl/cdat.h > > > +++ b/drivers/cxl/cdat.h > > > @@ -83,17 +83,38 @@ > > > #define CDAT_SSLBIS_ENTRY_PORT_Y(entry, i) (((entry)[4 + (i) * 2] & 0xffff0000) >> 16) > > > #define CDAT_SSLBIS_ENTRY_LAT_OR_BW(entry, i) ((entry)[4 + (i) * 2 + 1] & 0x0000ffff) > > > > > > +/** > > > + * struct cxl_dsmas - host unmarshaled version of DSMAS data > > > + * > > > + * As defined in the Coherent Device Attribute Table (CDAT) specification this > > > + * represents a single DSMAS entry in that table. > > > + * > > > + * @dpa_base: The lowest DPA address associated with this DSMAD > > > + * @dpa_length: Length in bytes of this DSMAD > > > + * @non_volatile: If set, the memory region represents Non-Volatile memory > > > + */ > > > +struct cxl_dsmas { > > > + u64 dpa_base; > > > + u64 dpa_length; > > > + /* Flags */ > > > + u8 non_volatile:1; > > > +}; > > > + > > > /** > > > * struct cxl_cdat - CXL CDAT data > > > * > > > * @table: cache of CDAT table > > > * @length: length of cached CDAT table > > > * @seq: Last read Sequence number of the CDAT table > > > + * @dsmas_ary: Array of DSMAS entries as parsed from the CDAT table > > > + * @nr_dsmas: Number of entries in dsmas_ary > > > */ > > > struct cxl_cdat { > > > void *table; > > > size_t length; > > > u32 seq; > > > + struct cxl_dsmas *dsmas_ary; > > > + int nr_dsmas; > > > }; > > > > > > #endif /* !__CXL_CDAT_H__ */ > > > diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c > > > index 11d721c56f08..32342a15e991 100644 > > > --- a/drivers/cxl/core/memdev.c > > > +++ b/drivers/cxl/core/memdev.c > > > @@ -6,6 +6,7 @@ > > > #include > > > #include > > > #include > > > +#include "cdat.h" > > > #include "core.h" > > > > > > static DECLARE_RWSEM(cxl_memdev_rwsem); > > > @@ -386,6 +387,71 @@ static int read_cdat_data(struct cxl_memdev *cxlmd, > > > return rc; > > > } > > > > > > +static int parse_dsmas(struct cxl_memdev *cxlmd) > > > +{ > > > + struct cxl_dsmas *dsmas_ary = NULL; > > > + u32 *data = cxlmd->cdat.table; > > > + int bytes_left = cxlmd->cdat.length; > > > + int nr_dsmas = 0; > > > + > > > + if (!data) > > > + return -ENXIO; > > > + > > > + /* Skip header */ > > > + data += CDAT_HEADER_LENGTH_DW; > > > + bytes_left -= CDAT_HEADER_LENGTH_BYTES; > > > + > > > + while (bytes_left > 0) { > > > + u32 *cur_rec = data; > > > + u8 type = FIELD_GET(CDAT_STRUCTURE_DW0_TYPE, cur_rec[0]); > > > + u16 length = FIELD_GET(CDAT_STRUCTURE_DW0_LENGTH, cur_rec[0]); > > > + > > > + if (type == CDAT_STRUCTURE_DW0_TYPE_DSMAS) { > > > + struct cxl_dsmas *new_ary; > > > + u8 flags; > > > + > > > + new_ary = devm_krealloc(&cxlmd->dev, dsmas_ary, > > > + sizeof(*dsmas_ary) * (nr_dsmas + 1), > > > + GFP_KERNEL); > > > + if (!new_ary) { > > > + dev_err(&cxlmd->dev, > > > + "Failed to allocate memory for DSMAS data\n"); > > > + return -ENOMEM; > > > + } > > > > One thought here - it looks like there are at most 256 DSMAS entries. You could > > allocate the full 256 up front, and then realloc *down* to the actual number. > > > > > + dsmas_ary = new_ary; > > > + > > > + flags = FIELD_GET(CDAT_DSMAS_DW1_FLAGS, cur_rec[1]); > > > + > > > + dsmas_ary[nr_dsmas].dpa_base = CDAT_DSMAS_DPA_OFFSET(cur_rec); > > > + dsmas_ary[nr_dsmas].dpa_length = CDAT_DSMAS_DPA_LEN(cur_rec); > > > + dsmas_ary[nr_dsmas].non_volatile = CDAT_DSMAS_NON_VOLATILE(flags); > > > + > > > + dev_dbg(&cxlmd->dev, "DSMAS %d: %llx:%llx %s\n", > > > + nr_dsmas, > > > + dsmas_ary[nr_dsmas].dpa_base, > > > + dsmas_ary[nr_dsmas].dpa_base + > > > + dsmas_ary[nr_dsmas].dpa_length, > > > + (dsmas_ary[nr_dsmas].non_volatile ? > > > + "Persistent" : "Volatile") > > > + ); > > > + > > > + nr_dsmas++; > > > + } > > > + > > > + data += (length / sizeof(u32)); > > > + bytes_left -= length; > > > + } > > > + > > > + if (nr_dsmas == 0) > > > + return -ENXIO; > > > > Hmm is there documentation that suggests a DSMAS must be implemented? Could this > > just return 0? I'd put maybe dev_dbg here if it's unexpected but not a failure > > and return success. > > For this call I was not envisioning this as an error. I wanted to leave it up > to the caller. > > I think it would make more sense to return the number of DSMAS' found or > negative errno on failure... > > I'll clean it up. Including below... > > > > > > + > > > + dev_dbg(&cxlmd->dev, "Found %d DSMAS entries\n", nr_dsmas); > > > + cxlmd->cdat.dsmas_ary = dsmas_ary; > > > + cxlmd->cdat.nr_dsmas = nr_dsmas; > > > + > > > + return 0; > > > +} > > > + > > > struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds) > > > { > > > struct cxl_memdev *cxlmd; > > > @@ -407,6 +473,10 @@ struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds) > > > if (rc) > > > goto err; > > > > > > + rc = parse_dsmas(cxlmd); > > > + if (rc) > > > + dev_warn(dev, "No DSMAS data found: %d\n", rc); > > > + > > This was changed to dev_warn() because I think here we do expect dsmas data? > Don't we? There are flags in the CXL Range registers that specify that some stuff is communicated via CDAT. That includes one for whether it is nonvolatile or not which is a DSMAS flag. So if that is set we definitely expect them. We would also expect them if QTG _DSM is in use as that has specific references to DMSAS regions. More generally a switch implementing CDAT wouldn't have DSMAS but we are fairly safe that if a memory device has CDAT at all, DSMAS is expected because most of the other structures reference the DSMAS handle. Message is in general wrong though as it could be a memory failure in parse_dsmas() so you need to check the actual error code. J > > Thanks, > Ira > > > > /* > > > * Activate ioctl operations, no cxl_memdev_rwsem manipulation > > > * needed as this is ordered with cdev_add() publishing the device. > > > -- > > > 2.31.1 > > >