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 X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C4EBC4332E for ; Thu, 14 Jan 2021 18:10:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 59B5E23A50 for ; Thu, 14 Jan 2021 18:10:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729500AbhANSJw (ORCPT ); Thu, 14 Jan 2021 13:09:52 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:2350 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727533AbhANSJu (ORCPT ); Thu, 14 Jan 2021 13:09:50 -0500 Received: from fraeml734-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4DGsfc4sVyz67bdg; Fri, 15 Jan 2021 02:05:12 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml734-chm.china.huawei.com (10.206.15.215) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Thu, 14 Jan 2021 19:09:08 +0100 Received: from localhost (10.47.30.252) 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 15.1.2106.2; Thu, 14 Jan 2021 18:09:07 +0000 Date: Thu, 14 Jan 2021 18:08:26 +0000 From: Jonathan Cameron To: Ben Widawsky CC: , , , "linux-acpi@vger.kernel.org, Ira Weiny" , Dan Williams , "Vishal Verma" , "Kelley, Sean V" , Rafael Wysocki , "Bjorn Helgaas" , Jon Masters , Chris Browy , Randy Dunlap , "Christoph Hellwig" , Subject: Re: [RFC PATCH v3 15/16] cxl/mem: Add limited Get Log command (0401h) Message-ID: <20210114180826.000072f0@Huawei.com> In-Reply-To: <20210111225121.820014-17-ben.widawsky@intel.com> References: <20210111225121.820014-1-ben.widawsky@intel.com> <20210111225121.820014-17-ben.widawsky@intel.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.30.252] 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-kernel@vger.kernel.org On Mon, 11 Jan 2021 14:51:20 -0800 Ben Widawsky wrote: > The Get Log command returns the actual log entries that are advertised > via the Get Supported Logs command (0400h). CXL device logs are selected > by UUID which is part of the CXL spec. Because the driver tries to > sanitize what is sent to hardware, there becomes a need to restrict the > types of logs which can be accessed by userspace. For example, the > vendor specific log might only be consumable by proprietary, or offline > applications, and therefore a good candidate for userspace. > > The current driver infrastructure does allow basic validation for all > commands, but doesn't inspect any of the payload data. Along with Get > Log support comes new infrastructure to add a hook for payload > validation. This infrastructure is used to filter out the CEL UUID, > which the userspace driver doesn't have business knowing, and taints on > invalid UUIDs being sent to hardware. > > Signed-off-by: Ben Widawsky Just a minor question for this one. Thanks, J ... \ > @@ -515,6 +529,15 @@ static int handle_mailbox_cmd_from_user(struct cxl_memdev *cxlmd, > int rc; > > if (cmd->info.size_in) { > + if (cmd->validate_payload) { > + rc = cmd->validate_payload(u64_to_user_ptr(in_payload), > + cmd->info.size_in); Is it worth moving this out of the region in which we hold the mbox? (after fixing the bug that I think means we don't actually hold it at this point) Perhaps not, but it does feel odd to do validation under the lock. > + if (rc) { > + cxl_mem_mbox_put(cxlmd->cxlm); > + return -EFAULT; > + } > + } > + > /* > * Directly copy the userspace payload into the hardware. UAPI > * states that the buffer must already be little endian.