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Mon, 18 May 2020 11:08:35 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3A122A404D; Mon, 18 May 2020 11:08:35 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 464CCA4053; Mon, 18 May 2020 11:08:32 +0000 (GMT) Received: from vajain21-in-ibm-com (unknown [9.102.2.238]) by d06av23.portsmouth.uk.ibm.com (Postfix) with SMTP; Mon, 18 May 2020 11:08:32 +0000 (GMT) Received: by vajain21-in-ibm-com (sSMTP sendmail emulation); Mon, 18 May 2020 16:38:31 +0530 From: Vaibhav Jain To: linuxppc-dev@lists.ozlabs.org, linux-nvdimm@lists.01.org Subject: [RFC PATCH 3/4] powerpc/papr_scm: Implement support for PAPR_SCM_PDSM_READ_PERF_STATS Date: Mon, 18 May 2020 16:38:13 +0530 Message-Id: <20200518110814.145644-4-vaibhav@linux.ibm.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200518110814.145644-1-vaibhav@linux.ibm.com> References: <20200518110814.145644-1-vaibhav@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216,18.0.676 definitions=2020-05-18_04:2020-05-15,2020-05-18 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 mlxscore=0 lowpriorityscore=0 mlxlogscore=999 spamscore=0 clxscore=1015 impostorscore=0 adultscore=0 malwarescore=0 priorityscore=1501 bulkscore=0 suspectscore=0 cotscore=-2147483648 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2005180100 Message-ID-Hash: N5TMGPX6L7JW35FQWBAMWESZTBI46TXU X-Message-ID-Hash: N5TMGPX6L7JW35FQWBAMWESZTBI46TXU X-MailFrom: vaibhav@linux.ibm.com X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation CC: Vaibhav Jain , "Aneesh Kumar K . V" , Michael Ellerman X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Implement support for pdsm READ_PERF_STATS to be used by libndctl to fetch all NVDIMM performance statistics. The stats are to be exchanged via newly introduced 'struct nd_pdsm_get_perf_stats' which is allocated and sent by libndctl to papr_scm. The struct contains members 'in_offset' and 'in_length' to provide incremental access to performance statistics data buffer and workaround 'libnvdimm' limit of 256 bytes evelope size. The patch introduces new function 'papr_scm_read_perf_stats()' to service this pdsm and copy the requested chunk of performance stats to the libndctl provided payload buffer for the given offset and length. Signed-off-by: Vaibhav Jain --- arch/powerpc/include/uapi/asm/papr_scm_pdsm.h | 35 +++++++ arch/powerpc/platforms/pseries/papr_scm.c | 91 +++++++++++++++++++ 2 files changed, 126 insertions(+) diff --git a/arch/powerpc/include/uapi/asm/papr_scm_pdsm.h b/arch/powerpc/include/uapi/asm/papr_scm_pdsm.h index 40ec55d06f4c..2db4ffdff285 100644 --- a/arch/powerpc/include/uapi/asm/papr_scm_pdsm.h +++ b/arch/powerpc/include/uapi/asm/papr_scm_pdsm.h @@ -115,6 +115,7 @@ enum papr_scm_pdsm { PAPR_SCM_PDSM_MIN = 0x0, PAPR_SCM_PDSM_HEALTH, PAPR_SCM_PDSM_FETCH_PERF_STATS, + PAPR_SCM_PDSM_READ_PERF_STATS, PAPR_SCM_PDSM_MAX, }; @@ -183,4 +184,38 @@ struct nd_pdsm_fetch_perf_stats_v1 { #define nd_pdsm_fetch_perf_stats nd_pdsm_fetch_perf_stats_v1 #define ND_PDSM_FETCH_PERF_STATS_VERSION 1 +/* + * Holds a single performance stat. papr_scm owns a buffer that holds an array + * of all the available stats and their values. Access to the buffer is provided + * via PERF_STAT_SIZE and READ_PERF_STATS psdm. + * id : id of the performance stat. Usually acsii encode stat name. + * val : Non normalized value of the id. + */ + +struct nd_pdsm_perf_stat { + __u64 id; + __u64 val; +}; + +/* + * Returns a chunk of performance stats buffer data to libndctl. + * This is needed to overcome the 256 byte envelope size limit enforced by + * libnvdimm. + * in_offset: The starting offset to perf stats data buffer. + * in_length: Length of data to be copied to 'stats_data' + * stats_data: Holds the chunk of requested perf stats data buffer. + * + * Note: To prevent races in reading performance stats, in_offset and in_length + * should multiple of 16-Bytes. If they are not then papr_scm will return an + * -EINVAL error. + */ +struct nd_pdsm_read_perf_stats_v1 { + __u32 in_offset; + __u32 in_length; + struct nd_pdsm_perf_stat stats_data[]; +} __packed; + +#define nd_pdsm_read_perf_stats nd_pdsm_read_perf_stats_v1 +#define ND_PDSM_READ_PERF_STATS_VERSION 1 + #endif /* _UAPI_ASM_POWERPC_PAPR_SCM_PDSM_H_ */ diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index f8b37a830aed..06744d7fe727 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -525,6 +525,94 @@ static int is_cmd_valid(struct nvdimm *nvdimm, unsigned int cmd, void *buf, return 0; } +/* + * Read the contents of dimm performance statistics buffer at the given + * 'in_offset' and copy 'in_length' number of bytes to the pkg payload. + * Both 'in_offset' and 'in_length' are expected to be in multiples of + * 16-Bytes to prevent a read/write race that may cause malformed values + * top be returned as performance statistics buffer content. + */ +static int papr_scm_read_perf_stats(struct papr_scm_priv *p, + struct nd_pdsm_cmd_pkg *pkg) +{ + int rc; + struct nd_pdsm_read_perf_stats *stats = + (struct nd_pdsm_read_perf_stats *)pdsm_cmd_to_payload(pkg); + const size_t copysize = sizeof(struct nd_pdsm_read_perf_stats); + off_t offset; + + /* + * If the requested payload version is greater than one we know + * about, return the payload version we know about and let + * caller/userspace handle. + */ + if (pkg->payload_version > ND_PDSM_READ_PERF_STATS_VERSION) + pkg->payload_version = ND_PDSM_READ_PERF_STATS_VERSION; + + if (pkg->hdr.nd_size_out < copysize) { + dev_dbg(&p->pdev->dev, "Truncated payload (%u). Expected (%lu)", + pkg->hdr.nd_size_out, copysize); + rc = -ENOSPC; + goto out; + } + + /* Protect concurrent modifications to papr_scm_priv */ + rc = mutex_lock_interruptible(&p->health_mutex); + if (rc) + goto out; + + if (!p->len_stat_buffer) { + dev_dbg(&p->pdev->dev, "Perf stats: req for unsupported device"); + rc = -ENOENT; + goto mutex_unlock_out; + } + + /* calculate offset skipping the perf_stats buffer header */ + offset = stats->in_offset + sizeof(*p->perf_stats); + /* Cap the copy length to extend of stats buffer */ + stats->in_length = min(stats->in_length, + (__u32)(p->len_stat_buffer - offset)); + + /* + * Ensure that offset and length are valid and multiples of 16 bytes. + * PDSM FETCH_PERF_STATS can interleave in between PDSM READ_PERF_STAT. + * Since this is a read/write race hence malformed performance stats + * buffer contents that may be returned. + * A 16-Byte read alignment constraint forces a read granularity of + * same the size of each performance stat and they are guaranteed to + * remain stable during 'health_mutex' lock context. + */ + if (offset >= p->len_stat_buffer || (offset % 16) || + (stats->in_length % 16)) { + dev_dbg(&p->pdev->dev, + "Perf stats: Invalid offset(0x%lx) or length(0x%x)", + offset, stats->in_length); + rc = -EINVAL; + goto mutex_unlock_out; + } + + /* Put the stats buffer data in the payload buffer */ + memcpy(stats->stats_data, + (void *)p->perf_stats + offset, stats->in_length); + + pkg->hdr.nd_fw_size = stats->in_length; + + dev_dbg(&p->pdev->dev, "Copying payload size=%u version=0x%x\n", + stats->in_length, pkg->payload_version); + +mutex_unlock_out: + mutex_unlock(&p->health_mutex); +out: + /* + * Put the error in out package and return success from function + * so that errors if any are propogated back to userspace. + */ + pkg->cmd_status = rc; + dev_dbg(&p->pdev->dev, "completion code = %d\n", rc); + + return 0; +} + /* Return the size in bytes for returning all perf stats to libndctl */ static int papr_scm_fetch_perf_stats(struct papr_scm_priv *p, struct nd_pdsm_cmd_pkg *pkg) @@ -664,6 +752,9 @@ static int papr_scm_service_pdsm(struct papr_scm_priv *p, case PAPR_SCM_PDSM_FETCH_PERF_STATS: return papr_scm_fetch_perf_stats(p, call_pkg); + case PAPR_SCM_PDSM_READ_PERF_STATS: + return papr_scm_read_perf_stats(p, call_pkg); + default: dev_dbg(&p->pdev->dev, "Unsupported PDSM request 0x%llx\n", call_pkg->hdr.nd_command); -- 2.26.2 _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org