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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 1A0D6C433E2 for ; Wed, 20 May 2020 10:22:26 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 760A5207C4 for ; Wed, 20 May 2020 10:22:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 760A5207C4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 49Rphv3SszzDqSZ for ; Wed, 20 May 2020 20:22:23 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=vaibhav@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 49RpfX4V35zDqWZ for ; Wed, 20 May 2020 20:20:19 +1000 (AEST) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 04KA2CrK001868; Wed, 20 May 2020 06:19:46 -0400 Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 312cb1g4f6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 May 2020 06:19:46 -0400 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 04KAGN8M024752; Wed, 20 May 2020 10:19:44 GMT Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by ppma03ams.nl.ibm.com with ESMTP id 313xas3dr0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 May 2020 10:19:43 +0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 04KAJfKo54001720 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 May 2020 10:19:41 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CA8A6A4055; Wed, 20 May 2020 10:19:41 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 47229A404D; Wed, 20 May 2020 10:19:39 +0000 (GMT) Received: from vajain21-in-ibm-com (unknown [9.85.92.5]) by d06av23.portsmouth.uk.ibm.com (Postfix) with SMTP; Wed, 20 May 2020 10:19:39 +0000 (GMT) Received: by vajain21-in-ibm-com (sSMTP sendmail emulation); Wed, 20 May 2020 15:49:37 +0530 From: Vaibhav Jain To: "Aneesh Kumar K.V" , linuxppc-dev@lists.ozlabs.org, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH v7 4/5] ndctl/papr_scm, uapi: Add support for PAPR nvdimm specific methods In-Reply-To: <87a723f5fs.fsf@linux.ibm.com> References: <20200519190058.257981-1-vaibhav@linux.ibm.com> <20200519190058.257981-5-vaibhav@linux.ibm.com> <87a723f5fs.fsf@linux.ibm.com> Date: Wed, 20 May 2020 15:49:37 +0530 Message-ID: <87y2pmx612.fsf@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.676 definitions=2020-05-20_05:2020-05-19, 2020-05-20 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 lowpriorityscore=0 mlxscore=0 suspectscore=1 spamscore=0 impostorscore=0 malwarescore=0 adultscore=0 bulkscore=0 clxscore=1015 mlxlogscore=999 priorityscore=1501 cotscore=-2147483648 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2005200083 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Steven Rostedt Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Thanks for reviewing this patch Aneesh. "Aneesh Kumar K.V" writes: > Vaibhav Jain writes: > > .... > > + >> +/* Papr-scm-header + payload expected with ND_CMD_CALL ioctl from libnvdimm */ >> +struct nd_pdsm_cmd_pkg { >> + struct nd_cmd_pkg hdr; /* Package header containing sub-cmd */ >> + __s32 cmd_status; /* Out: Sub-cmd status returned back */ >> + __u16 payload_offset; /* In: offset from start of struct */ >> + __u16 payload_version; /* In/Out: version of the payload */ >> + __u8 payload[]; /* In/Out: Sub-cmd data buffer */ >> +} __packed; > > that payload_offset can be avoided if we prevent userspace to user a > different variant of nd_pdsm_cmd_pkg which different header. We can keep > things simpler if we can always find payload at > nd_pdsm_cmd_pkg->payload. Had introduced this member to handle case where new fields are added to 'struct nd_pdsm_cmd_pkg' without having to break the ABI. But agree with the point that you made later that this can be simplified by replacing 'payload_offset' with a set of reserved variables. Will address this in next iteration of this patchset. > >> + >> +/* >> + * Methods to be embedded in ND_CMD_CALL request. These are sent to the kernel >> + * via 'nd_pdsm_cmd_pkg.hdr.nd_command' member of the ioctl struct >> + */ >> +enum papr_scm_pdsm { >> + PAPR_SCM_PDSM_MIN = 0x0, >> + PAPR_SCM_PDSM_MAX, >> +}; >> + >> +/* Convert a libnvdimm nd_cmd_pkg to pdsm specific pkg */ >> +static inline struct nd_pdsm_cmd_pkg *nd_to_pdsm_cmd_pkg(struct nd_cmd_pkg *cmd) >> +{ >> + return (struct nd_pdsm_cmd_pkg *) cmd; >> +} >> + >> +/* Return the payload pointer for a given pcmd */ >> +static inline void *pdsm_cmd_to_payload(struct nd_pdsm_cmd_pkg *pcmd) >> +{ >> + if (pcmd->hdr.nd_size_in == 0 && pcmd->hdr.nd_size_out == 0) >> + return NULL; >> + else >> + return (void *)((__u8 *) pcmd + pcmd->payload_offset); >> +} >> + > > we need to make sure userspace is not passing a wrong payload_offset. Agree, that this function should have more strict checking for payload_offset field. However will be getting rid of 'payload_offset' all together in the next iteration as you previously suggested. > and in the next patch you do > > + /* Copy the health struct to the payload */ > + memcpy(pdsm_cmd_to_payload(pkg), &p->health, copysize); > + pkg->hdr.nd_fw_size = copysize; > + Yes this is already being done in the patchset and changes proposed to this pdsm_cmd_to_payload() should not impact other patches as pdsm_cmd_to_payload() abstracts rest of the code from how to access the payload. > All this can be simplified if you can keep payload at > nd_pdsm_cmd_pkg->payload. > > If you still want to have the ability to extend the header, then added a > reserved field similar to nd_cmd_pkg. > Agree to this and will address this in V8. > > -aneesh -- Cheers ~ Vaibhav