From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 449ED20DD74; Fri, 10 Jan 2025 14:59:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736521165; cv=none; b=l2lx1MgDt6M5pD4tvpWuwGzBn6GcVHVhrnpNlj65MJ4tuK4VrjkNFAm5Tch0mNMCq7Hw5E6ZAHWAWr/9G+q8Vqhp9yFlhXo2VK1jvlG54SOz1bkEPHz1CTSrOvJTSKC55MvgJ/pIC0+BqJuhYzg+SOZw0gL1Hfcvx+RgqXlCW7k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736521165; c=relaxed/simple; bh=qoN4csxcH42JEKIUwkPsIuRENnJhK9htZfI1jnoH3+s=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=EkulwvQzcfNIX9P+ib9CrqABemCzwNPbGe9eRSrspFDsChJ9FVhXYyTzZ3WKaqBYQYE7XFdpYiAVAClOU8E0vktkfe+qkZM1KNmLRIUkc83ZVL2FQ4t0qA1aKC+qcE4SaPMsTE0DOmkzOmvVJeS7qv76UMdhuIkwpnjUZJF6mFg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.31]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4YV4Wn6WSVz6D9CW; Fri, 10 Jan 2025 22:57:41 +0800 (CST) Received: from frapeml500008.china.huawei.com (unknown [7.182.85.71]) by mail.maildlp.com (Postfix) with ESMTPS id C32001403D2; Fri, 10 Jan 2025 22:59:19 +0800 (CST) Received: from localhost (10.203.177.66) by frapeml500008.china.huawei.com (7.182.85.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Fri, 10 Jan 2025 15:59:19 +0100 Date: Fri, 10 Jan 2025 14:59:17 +0000 From: Jonathan Cameron To: Dave Jiang CC: , , , , , , , , Subject: Re: [PATCH 3/4] cxl: Add extended linear cache address alias emission for cxl events Message-ID: <20250110145917.00006541@huawei.com> In-Reply-To: References: <20241204224827.2097263-1-dave.jiang@intel.com> <20241204224827.2097263-4-dave.jiang@intel.com> <20241224121113.00007eec@huawei.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml500009.china.huawei.com (7.191.174.84) To frapeml500008.china.huawei.com (7.182.85.71) On Tue, 7 Jan 2025 12:41:46 -0700 Dave Jiang wrote: > On 12/24/24 5:11 AM, Jonathan Cameron wrote: > > On Wed, 4 Dec 2024 15:46:48 -0700 > > Dave Jiang wrote: > > > >> Add the aliased address of extended linear cache when emitting event > >> trace for DRAM and general media of CXL events. > >> > >> Signed-off-by: Dave Jiang > > I wonder if you want to future proof the hpa_alias for potential case > > of there being more than 1? hpa_alias0 or similar so that we can add > > more as needed? > > Do you mean when emitting via the trace? Yeah I can change it to hpa_alias0 in the output string. > err. Can't entirely remember what I meant but that seems sensible ;) > > > > > > > Otherwise, looks like there is either a null point dereference or > > overly paranoid existing code. I haven't checked which but changes > > needed either way. > > I'll move it under the if (cxlr) and also add a check for cxlr in the helper function. > > DJ > > > > > > Jonathan > > > >> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c > >> index 5175138c4fb7..4017b7afa78a 100644 > >> --- a/drivers/cxl/core/mbox.c > >> +++ b/drivers/cxl/core/mbox.c > >> @@ -856,6 +856,24 @@ int cxl_enumerate_cmds(struct cxl_memdev_state *mds) > >> } > >> EXPORT_SYMBOL_NS_GPL(cxl_enumerate_cmds, CXL); > >> > >> +static u64 cxlr_hpa_cache_alias(struct cxl_region *cxlr, u64 hpa) > >> +{ > >> + struct cxl_region_params *p = &cxlr->params; > > > > Bad idea to unconditionally dereference I think. See below. > > > >> + int nid; > >> + > >> + if (!p->cache_size) > >> + return ~0ULL; > >> + > >> + nid = cxl_region_nid(cxlr); > >> + if (nid == NUMA_NO_NODE) > >> + nid = 0; > >> + > >> + if (hpa >= p->res->start + p->cache_size) > >> + return hpa - p->cache_size; > >> + > >> + return hpa + p->cache_size; > >> +} > >> + > >> void cxl_event_trace_record(const struct cxl_memdev *cxlmd, > >> enum cxl_event_log_type type, > >> enum cxl_event_type event_type, > >> @@ -871,7 +889,7 @@ void cxl_event_trace_record(const struct cxl_memdev *cxlmd, > >> } > >> > >> if (trace_cxl_general_media_enabled() || trace_cxl_dram_enabled()) { > >> - u64 dpa, hpa = ULLONG_MAX; > >> + u64 dpa, hpa = ULLONG_MAX, hpa_alias; > >> struct cxl_region *cxlr; > >> > >> /* > >> @@ -887,11 +905,14 @@ void cxl_event_trace_record(const struct cxl_memdev *cxlmd, > >> if (cxlr) > >> hpa = cxl_dpa_to_hpa(cxlr, cxlmd, dpa); > >> > >> + hpa_alias = cxlr_hpa_cache_alias(cxlr, hpa); > > > > If there is no region, and hence no hpa does it make sense to call this? > > Particularly as first thing done in this is to dereference cxlr. > > > > > >> + > >> if (event_type == CXL_CPER_EVENT_GEN_MEDIA) > >> trace_cxl_general_media(cxlmd, type, cxlr, hpa, > >> - &evt->gen_media); > >> + hpa_alias, &evt->gen_media); > >> else if (event_type == CXL_CPER_EVENT_DRAM) > >> - trace_cxl_dram(cxlmd, type, cxlr, hpa, &evt->dram); > >> + trace_cxl_dram(cxlmd, type, cxlr, hpa, hpa_alias, > >> + &evt->dram); > >> } > >> } > >> EXPORT_SYMBOL_NS_GPL(cxl_event_trace_record, CXL); > > > >