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 D7954C433EF for ; Thu, 30 Jun 2022 16:34:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235741AbiF3Qep (ORCPT ); Thu, 30 Jun 2022 12:34:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235389AbiF3Qen (ORCPT ); Thu, 30 Jun 2022 12:34:43 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38D353B299; Thu, 30 Jun 2022 09:34:42 -0700 (PDT) Received: from fraeml737-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4LYkRf6HsZz6885F; Fri, 1 Jul 2022 00:33:50 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml737-chm.china.huawei.com (10.206.15.218) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 30 Jun 2022 18:34:39 +0200 Received: from localhost (10.81.200.250) 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 15.1.2375.24; Thu, 30 Jun 2022 17:34:38 +0100 Date: Thu, 30 Jun 2022 17:34:37 +0100 From: Jonathan Cameron To: Dan Williams CC: , , , , , "Ben Widawsky" Subject: Re: [PATCH 40/46] cxl/region: Attach endpoint decoders Message-ID: <20220630173437.0000604d@Huawei.com> In-Reply-To: <20220624041950.559155-15-dan.j.williams@intel.com> References: <165603869943.551046.3498980330327696732.stgit@dwillia2-xfh> <20220624041950.559155-15-dan.j.williams@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: [10.81.200.250] X-ClientProxiedBy: lhreml754-chm.china.huawei.com (10.201.108.204) 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, 23 Jun 2022 21:19:44 -0700 Dan Williams wrote: > CXL regions (interleave sets) are made up of a set of memory devices > where each device maps a portion of the interleave with one of its > decoders (see CXL 2.0 8.2.5.12 CXL HDM Decoder Capability Structure). > As endpoint decoders are identified by a provisioning tool they can be > added to a region provided the region interleave properties are set > (way, granularity, HPA) and DPA has been assigned to the decoder. > > The attach event triggers several validation checks, for example: > - is the DPA sized appropriately for the region > - is the decoder reachable via the host-bridges identified by the > region's root decoder > - is the device already active in a different region position slot > - are there already regions with a higher HPA active on a given port > (per CXL 2.0 8.2.5.12.20 Committing Decoder Programming) > > ...and the attach event affords an opportunity to collect data and > resources relevant to later programming the target lists in switch > decoders, for example: > - allocate a decoder at each cxl_port in the decode chain > - for a given switch port, how many the region's endpoints are hosted > through the port > - how many unique targets (next hops) does a port need to map to reach > those endpoints > > The act of reconciling this information and deploying it to the decoder > configuration is saved for a follow-on patch. > > Co-developed-by: Ben Widawsky > Signed-off-by: Ben Widawsky > Signed-off-by: Dan Williams > --- > drivers/cxl/core/core.h | 7 + > drivers/cxl/core/port.c | 10 +- > drivers/cxl/core/region.c | 338 +++++++++++++++++++++++++++++++++++++- > drivers/cxl/cxl.h | 20 +++ > drivers/cxl/cxlmem.h | 5 + > 5 files changed, 372 insertions(+), 8 deletions(-) > > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index 4830365f3857..65bf84abad57 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -428,6 +428,254 @@ static size_t show_targetN(struct cxl_region *cxlr, char *buf, int pos) > return rc; > } > > + > +static struct cxl_region_ref *alloc_region_ref(struct cxl_port *port, > + struct cxl_region *cxlr) > +{ > + struct cxl_region_ref *cxl_rr; > + > + cxl_rr = kzalloc(sizeof(*cxl_rr), GFP_KERNEL); > + if (!cxl_rr) > + return NULL; > + cxl_rr->port = port; > + cxl_rr->region = cxlr; > + xa_init(&cxl_rr->endpoints); > + return cxl_rr; > +} > + > +static void free_region_ref(struct cxl_region_ref *cxl_rr) > +{ > + struct cxl_port *port = cxl_rr->port; > + struct cxl_region *cxlr = cxl_rr->region; > + struct cxl_decoder *cxld = cxl_rr->decoder; > + > + dev_WARN_ONCE(&cxlr->dev, cxld->region != cxlr, "region mismatch\n"); > + if (cxld->region == cxlr) { > + cxld->region = NULL; > + put_device(&cxlr->dev); > + } > + > + xa_erase(&port->regions, (unsigned long)cxlr); Why do we have things in a free_ function that aren't simply removing things created in the alloc()? I'd kind of expect this to be in a cxl_rr_del() or similar. > + xa_destroy(&cxl_rr->endpoints); > + kfree(cxl_rr); > +} > + > +static int cxl_rr_add(struct cxl_region_ref *cxl_rr) > +{ > + struct cxl_port *port = cxl_rr->port; > + struct cxl_region *cxlr = cxl_rr->region; > + > + return xa_insert(&port->regions, (unsigned long)cxlr, cxl_rr, > + GFP_KERNEL); > +} > + > +static int cxl_rr_ep_add(struct cxl_region_ref *cxl_rr, > + struct cxl_endpoint_decoder *cxled) > +{ > + int rc; > + struct cxl_port *port = cxl_rr->port; > + struct cxl_region *cxlr = cxl_rr->region; > + struct cxl_decoder *cxld = cxl_rr->decoder; > + struct cxl_ep *ep = cxl_ep_load(port, cxled_to_memdev(cxled)); > + > + rc = xa_insert(&cxl_rr->endpoints, (unsigned long)cxled, ep, > + GFP_KERNEL); > + if (rc) > + return rc; > + cxl_rr->nr_eps++; > + > + if (!cxld->region) { > + cxld->region = cxlr; > + get_device(&cxlr->dev); > + } > + > + return 0; > +} > + > +static int cxl_port_attach_region(struct cxl_port *port, > + struct cxl_region *cxlr, > + struct cxl_endpoint_decoder *cxled, int pos) > +{ > + struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); > + struct cxl_ep *ep = cxl_ep_load(port, cxlmd); > + struct cxl_region_ref *cxl_rr = NULL, *iter; > + struct cxl_region_params *p = &cxlr->params; > + struct cxl_decoder *cxld = NULL; > + unsigned long index; > + int rc = -EBUSY; > + > + lockdep_assert_held_write(&cxl_region_rwsem); This function is complex enough that maybe it would benefit from some saying what each part is doing. > + > + xa_for_each(&port->regions, index, iter) { > + struct cxl_region_params *ip = &iter->region->params; > + > + if (iter->region == cxlr) > + cxl_rr = iter; > + if (ip->res->start > p->res->start) { > + dev_dbg(&cxlr->dev, > + "%s: HPA order violation %s:%pr vs %pr\n", > + dev_name(&port->dev), > + dev_name(&iter->region->dev), ip->res, p->res); > + return -EBUSY; > + } > + } > + > + if (cxl_rr) { > + struct cxl_ep *ep_iter; > + int found = 0; > + > + cxld = cxl_rr->decoder; > + xa_for_each(&cxl_rr->endpoints, index, ep_iter) { > + if (ep_iter == ep) > + continue; > + if (ep_iter->next == ep->next) { > + found++; > + break; > + } > + } > + > + /* > + * If this is a new target or if this port is direct connected > + * to this endpoint then add to the target count. > + */ > + if (!found || !ep->next) > + cxl_rr->nr_targets++; > + } else { > + cxl_rr = alloc_region_ref(port, cxlr); > + if (!cxl_rr) { > + dev_dbg(&cxlr->dev, > + "%s: failed to allocate region reference\n", > + dev_name(&port->dev)); > + return -ENOMEM; > + } > + rc = cxl_rr_add(cxl_rr); > + if (rc) { > + dev_dbg(&cxlr->dev, > + "%s: failed to track region reference\n", > + dev_name(&port->dev)); > + kfree(cxl_rr); > + return rc; > + } > + } > + > + if (!cxld) { > + if (port == cxled_to_port(cxled)) > + cxld = &cxled->cxld; > + else > + cxld = cxl_region_find_decoder(port, cxlr); > + if (!cxld) { > + dev_dbg(&cxlr->dev, "%s: no decoder available\n", > + dev_name(&port->dev)); > + goto out_erase; > + } > + > + if (cxld->region) { > + dev_dbg(&cxlr->dev, "%s: %s already attached to %s\n", > + dev_name(&port->dev), dev_name(&cxld->dev), > + dev_name(&cxld->region->dev)); > + rc = -EBUSY; > + goto out_erase; > + } > + > + cxl_rr->decoder = cxld; > + } > + > + rc = cxl_rr_ep_add(cxl_rr, cxled); > + if (rc) { > + dev_dbg(&cxlr->dev, > + "%s: failed to track endpoint %s:%s reference\n", > + dev_name(&port->dev), dev_name(&cxlmd->dev), > + dev_name(&cxld->dev)); > + goto out_erase; > + } > + > + return 0; > +out_erase: > + if (cxl_rr->nr_eps == 0) > + free_region_ref(cxl_rr); > + return rc; > +} > + > > static void cxl_region_detach(struct cxl_endpoint_decoder *cxled) > { > + struct cxl_port *iter, *ep_port = cxled_to_port(cxled); > struct cxl_region *cxlr = cxled->cxld.region; > struct cxl_region_params *p; > > @@ -481,6 +811,10 @@ static void cxl_region_detach(struct cxl_endpoint_decoder *cxled) > p = &cxlr->params; > get_device(&cxlr->dev); > > + for (iter = ep_port; !is_cxl_root(iter); > + iter = to_cxl_port(iter->dev.parent)) > + cxl_port_detach_region(iter, cxlr, cxled); > + > if (cxled->pos < 0 || cxled->pos >= p->interleave_ways || > p->targets[cxled->pos] != cxled) { > struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); > @@ -491,6 +825,8 @@ static void cxl_region_detach(struct cxl_endpoint_decoder *cxled) > goto out; > } > > + if (p->state == CXL_CONFIG_ACTIVE) I 'think' the state is either CXL_CONFIG_ACTIVE or CXL_CONFIG_INTERLEAVE_ACTIVE, so you could set this unconditionally. A comment here on permissible states would be useful for future reference. > + p->state = CXL_CONFIG_INTERLEAVE_ACTIVE; > p->targets[cxled->pos] = NULL; > p->nr_targets--;