From patchwork Fri Aug 4 19:31:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alison Schofield X-Patchwork-Id: 13342302 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 D0CBBC41513 for ; Fri, 4 Aug 2023 19:32:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229487AbjHDTcB (ORCPT ); Fri, 4 Aug 2023 15:32:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230118AbjHDTbu (ORCPT ); Fri, 4 Aug 2023 15:31:50 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69CEA5248 for ; Fri, 4 Aug 2023 12:31:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1691177504; x=1722713504; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=fiqsPXOPbCE8vWsqIhRsUdfKNAfi47IFmZAtG895J0A=; b=XeHrCaeuYd4pzxM3pZuU8I/440UwZQiSTlArXfJlFwHFnPJDWejl2d+n Ysc20SnAziejymJs/1tMKQQxpXyZx92TQntdxIfBv0wVzYLGDoeWqdF7l XIIlg/oPq7hlsv44+6Nt2c89osbRdIf964dvKKSqpZBLLyF8uHHjaWde0 79gYaXB2Xlved/aW2ktcQEnr7DeHSWyz/DcizZKmLybM6vw+UtGIcsOEC 6b5GazEXcUSji9fCzy1LcJdle904GwE2buyOPt/Dps09S/JHWSVmgCfGX KzwZ0FjI9ZljVN/nko6RyurFtemcJSrDpRkH3OSROjnwzNA074P8x+EGa Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10792"; a="369128147" X-IronPort-AV: E=Sophos;i="6.01,255,1684825200"; d="scan'208";a="369128147" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2023 12:31:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10792"; a="759690015" X-IronPort-AV: E=Sophos;i="6.01,255,1684825200"; d="scan'208";a="759690015" Received: from aschofie-mobl2.amr.corp.intel.com (HELO localhost) ([10.212.168.219]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2023 12:31:42 -0700 From: alison.schofield@intel.com To: Davidlohr Bueso , Jonathan Cameron , Dave Jiang , Alison Schofield , Vishal Verma , Ira Weiny , Dan Williams Cc: linux-cxl@vger.kernel.org Subject: [PATCH v2 1/2] cxl/region: Try to add a region resource to a soft reserved parent Date: Fri, 4 Aug 2023 12:31:39 -0700 Message-Id: <6cd07222f169d951921486306187e87951853035.1691176651.git.alison.schofield@intel.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org From: Alison Schofield During region autodiscovery, the region driver always inserts the region resource as a child of the root decoder, a CXL WINDOW. It has the effect of making a soft reserved resource, with an exactly matching address range, a child of the region resource. It looks like this in /proc/iomem: 2080000000-29dbfffffff : CXL Window 0 2080000000-247fffffff : region0 2080000000-247fffffff : Soft Reserved Search for soft reserved resources that include the region resource, and add the new region resource as a child of that found resource. If a soft reserved resource is not found, insert to the root decoder as usual. With this change, it looks like this: 2080000000-29dbfffffff : CXL Window 0 2080000000-247fffffff : Soft Reserved 2080000000-247fffffff : region0 This odd parenting only occurs when the resources are an exact match. When the region resource only uses part of a soft reserved resource, the parenting appears more logical like this: 2080000000-29dbfffffff : CXL Window 0 2080000000-287fffffff : Soft Reserved 2080000000-247fffffff : region0 Aside from the more logical appearance, this change is in preparation for further cleanup in region teardown. A follow-on patch intends to find and free soft reserved resources upon region teardown. Signed-off-by: Alison Schofield --- drivers/cxl/core/region.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index e115ba382e04..36c0c0dd5697 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -2709,6 +2709,28 @@ static int match_region_by_range(struct device *dev, void *data) return rc; } +static int insert_resource_soft_reserved(struct resource *soft_res, void *arg) +{ + struct resource *parent, *new, *res = arg; + bool found = false; + + parent = soft_res->parent; + if (!parent) + return 0; + + /* Caller provides a copy of soft_res. Find the actual resource. */ + for (new = parent->child; new; new = new->sibling) { + if (resource_contains(new, soft_res)) { + found = true; + break; + } + } + if (found) + return insert_resource(new, res) == 0; + + return 0; +} + /* Establish an empty region covering the given HPA range */ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, struct cxl_endpoint_decoder *cxled) @@ -2719,7 +2741,7 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, struct cxl_region_params *p; struct cxl_region *cxlr; struct resource *res; - int rc; + int rc = 0; do { cxlr = __create_region(cxlrd, cxled->mode, @@ -2755,7 +2777,13 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, *res = DEFINE_RES_MEM_NAMED(hpa->start, range_len(hpa), dev_name(&cxlr->dev)); - rc = insert_resource(cxlrd->res, res); + + /* Try inserting to a Soft Reserved parent, fallback to root decoder */ + if (walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED, 0, + res->start, res->end, res, + insert_resource_soft_reserved) != 1) + rc = insert_resource(cxlrd->res, res); + if (rc) { /* * Platform-firmware may not have split resources like "System From patchwork Fri Aug 4 19:31:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alison Schofield X-Patchwork-Id: 13342301 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 791A7C04A6A for ; Fri, 4 Aug 2023 19:32:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229481AbjHDTcB (ORCPT ); Fri, 4 Aug 2023 15:32:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230151AbjHDTbv (ORCPT ); Fri, 4 Aug 2023 15:31:51 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D7DA1BF for ; Fri, 4 Aug 2023 12:31:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1691177509; x=1722713509; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=OPyPz0adXyr83BC5OBo+vy4lWp3wct6X8V/gRz6m8C4=; b=O7MPBqfN9tHX4CL1x+GsuwDubiZIwOU16Rgsq3QNQ1Ld4KpSqqoxj5br wkVhC5RPe/37PIdflgoUBGINJM1r15DAt6uILctpCn5dOcluEOSS64BeI dXhY5qHr2hn1u9lxIvLXV/C3wDRvrM/kOzolxzR8X3wgHmbr8ikLHdrSz 904JOkJCQQS4ZVav5C73jmhc9USsO0EnE+ovxkmWe/lLZAYUOF0eeWztu ScTcOmVa16tIbSnF+u5eEWc6rssaToGs4kzxRjPH9RyQTYh4AAy1jsK8t o1OBYiF5d9wtwGzeVza4+2GeKaRKf2d8EQTcOIRyAnOBJNoDpvowMokYa Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10792"; a="369128151" X-IronPort-AV: E=Sophos;i="6.01,255,1684825200"; d="scan'208";a="369128151" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2023 12:31:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10792"; a="759690018" X-IronPort-AV: E=Sophos;i="6.01,255,1684825200"; d="scan'208";a="759690018" Received: from aschofie-mobl2.amr.corp.intel.com (HELO localhost) ([10.212.168.219]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Aug 2023 12:31:43 -0700 From: alison.schofield@intel.com To: Davidlohr Bueso , Jonathan Cameron , Dave Jiang , Alison Schofield , Vishal Verma , Ira Weiny , Dan Williams Cc: linux-cxl@vger.kernel.org Subject: [PATCH v2 2/2] cxl/region: Remove a soft reserved resource at region teardown Date: Fri, 4 Aug 2023 12:31:40 -0700 Message-Id: <2aa10593dbe6a4a8da35077aa492c8aacd363901.1691176651.git.alison.schofield@intel.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org From: Alison Schofield When CXL regions are created through autodiscovery their resource may be a child of a soft reserved resource. Today, when such a region is destroyed, its soft reserved resource remains in place. That means that the HPA range that the region could release, is actually unavailable for reuse. Free the soft reserved resource on region teardown by examining the alignment of the resources, and handling accordingly. The two resources, will be exactly aligned, partially aligned, or not aligned at all. |----------- "Soft Reserved" -----------| |-------------- "Region #" -------------| Exactly aligned. Any dangling children move up to a parent on removal. The removal of this soft reserved seems guaranteed, however, the availability of the address range for use depends on complete cleanup of the region child resources also. |----------- "Soft Reserved" -----------| |-------- "Region #" -------| or |----------- "Soft Reserved" -----------| |-------- "Region #" -------| Either start or end aligns. Unlike removing a resource, which simply moves child resources up the resource tree, adjustments fail if any child resources map the range being truncated. So, this one will fail for dangling child resources of the region. |---------- "Soft Reserved" ----------| |---- "Region #" ----| No alignment. Freeing the resource of a region in the middle is possible if no child resources map the leading or trailing address space. Signed-off-by: Alison Schofield --- drivers/cxl/core/region.c | 132 +++++++++++++++++++++++++++++++++++--- 1 file changed, 123 insertions(+), 9 deletions(-) diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 36c0c0dd5697..b8a02afa3514 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -569,22 +569,136 @@ static int alloc_hpa(struct cxl_region *cxlr, resource_size_t size) return 0; } +static int add_soft_reserved(struct resource *parent, resource_size_t start, + resource_size_t len, unsigned long flags) +{ + struct resource *res; + int rc; + + res = kmalloc(sizeof(*res), GFP_KERNEL); + if (!res) + return -ENOMEM; + + *res = DEFINE_RES_MEM_NAMED(start, len, "Soft Reserved"); + + res->desc = IORES_DESC_SOFT_RESERVED; + res->flags = res->flags | flags; + rc = insert_resource(parent, res); + if (rc) + kfree(res); + + return rc; +} + +static void remove_soft_reserved(struct cxl_region *cxlr, struct resource *soft, + resource_size_t start, resource_size_t end) +{ + struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(cxlr->dev.parent); + resource_size_t new_start, new_end; + struct resource *parent; + unsigned long flags; + int rc; + + /* Prevent new usage while removing or adjusting the resource */ + mutex_lock(&cxlrd->range_lock); + + /* Aligns at both resource start and end */ + if (soft->start == start && soft->end == end) { + rc = remove_resource(soft); + if (rc) + dev_dbg(&cxlr->dev, + "cannot remove soft reserved resource %pr\n", + soft); + else + kfree(soft); + + goto out; + } + + /* Aligns at either resource start or end */ + if (soft->start == start || soft->end == end) { + if (soft->start == start) { + new_start = end + 1; + new_end = soft->end; + } else { + new_start = soft->start; + new_end = start + 1; + } + rc = adjust_resource(soft, new_start, new_end - new_start + 1); + if (rc) + dev_dbg(&cxlr->dev, + "cannot adjust soft reserved resource %pr\n", + soft); + goto out; + } + + /* + * No alignment. Attempt a 3-way split that removes the part of + * the resource the region occupied, and then creates new soft + * reserved resources for the leading and trailing addr space. + * adjust_resource() will stop the attempt if there are any + * child resources. + */ + + /* Save the original soft reserved resource params before adjusting */ + new_start = soft->start; + new_end = soft->end; + parent = soft->parent; + flags = soft->flags; + + rc = adjust_resource(soft, start, end - start); + if (rc) { + dev_dbg(&cxlr->dev, + "cannot adjust soft reserved resource %pr\n", soft); + goto out; + } + rc = remove_resource(soft); + if (rc) + dev_warn(&cxlr->dev, + "cannot remove soft reserved resource %pr\n", soft); + + rc = add_soft_reserved(parent, new_start, start - new_start, flags); + if (rc) + dev_warn(&cxlr->dev, + "cannot add new soft reserved resource at %pa\n", + &new_start); + + rc = add_soft_reserved(parent, end + 1, new_end - end, flags); + if (rc) + dev_warn(&cxlr->dev, + "cannot add new soft reserved resource at %pa + 1\n", + &end); +out: + mutex_unlock(&cxlrd->range_lock); +} + static void cxl_region_iomem_release(struct cxl_region *cxlr) { struct cxl_region_params *p = &cxlr->params; + struct resource *parent, *res = p->res; + resource_size_t start, end; if (device_is_registered(&cxlr->dev)) lockdep_assert_held_write(&cxl_region_rwsem); - if (p->res) { - /* - * Autodiscovered regions may not have been able to insert their - * resource. - */ - if (p->res->parent) - remove_resource(p->res); - kfree(p->res); - p->res = NULL; + if (!res) + return; + /* + * Autodiscovered regions may not have been able to insert their + * resource. If a Soft Reserved parent resource exists, try to + * remove that also. + */ + if (p->res->parent) { + parent = p->res->parent; + start = p->res->start; + end = p->res->end; + remove_resource(p->res); + if (test_bit(CXL_REGION_F_AUTO, &cxlr->flags) && + parent->desc == IORES_DESC_SOFT_RESERVED) + remove_soft_reserved(cxlr, parent, start, end); } + + kfree(p->res); + p->res = NULL; } static int free_hpa(struct cxl_region *cxlr)