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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 A59D2C48BD6 for ; Wed, 26 Jun 2019 17:00:55 +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 3288420665 for ; Wed, 26 Jun 2019 17:00:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3288420665 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 lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45Yq6X2Cb9zDqX9 for ; Thu, 27 Jun 2019 03:00:52 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=linux.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=aneesh.kumar@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 (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 45Yq4P1GGvzDqGb for ; Thu, 27 Jun 2019 02:59:00 +1000 (AEST) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5QGwhZn155865 for ; Wed, 26 Jun 2019 12:58:57 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0b-001b2d01.pphosted.com with ESMTP id 2tca1dqesu-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 26 Jun 2019 12:58:56 -0400 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 26 Jun 2019 17:58:52 +0100 Received: from b06avi18626390.portsmouth.uk.ibm.com (9.149.26.192) by e06smtp01.uk.ibm.com (192.168.101.131) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 26 Jun 2019 17:58:50 +0100 Received: from d06av24.portsmouth.uk.ibm.com (mk.ibm.com [9.149.105.60]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5QGwdq037552468 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 26 Jun 2019 16:58:39 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 04E274203F; Wed, 26 Jun 2019 16:58:49 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B4A7742045; Wed, 26 Jun 2019 16:58:45 +0000 (GMT) Received: from skywalker.linux.ibm.com (unknown [9.102.1.130]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 26 Jun 2019 16:58:45 +0000 (GMT) X-Mailer: emacs 26.2 (via feedmail 11-beta-1 I) From: "Aneesh Kumar K.V" To: Vaibhav Jain , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v3 3/3] powerpc/papr_scm: Force a scm-unbind if initial scm-bind fails In-Reply-To: <20190626140404.27448-4-vaibhav@linux.ibm.com> References: <20190626140404.27448-1-vaibhav@linux.ibm.com> <20190626140404.27448-4-vaibhav@linux.ibm.com> Date: Wed, 26 Jun 2019 22:28:43 +0530 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 x-cbid: 19062616-4275-0000-0000-000003467EFB X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19062616-4276-0000-0000-0000385684E2 Message-Id: <87k1d8z3jw.fsf@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-06-26_09:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906260199 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: Laurent Dufour , Vaibhav Jain , David Gibson , Oliver O'Halloran Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Vaibhav Jain writes: > In some cases initial bind of scm memory for an lpar can fail if > previously it wasn't released using a scm-unbind hcall. This situation > can arise due to panic of the previous kernel or forced lpar > fadump. In such cases the H_SCM_BIND_MEM return a H_OVERLAP error. > > To mitigate such cases the patch updates papr_scm_probe() to force a > call to drc_pmem_unbind() in case the initial bind of scm memory fails > with EBUSY error. In case scm-bind operation again fails after the > forced scm-unbind then we follow the existing error path. We also > update drc_pmem_bind() to handle the H_OVERLAP error returned by phyp > and indicate it as a EBUSY error back to the caller. > > Suggested-by: "Oliver O'Halloran" > Signed-off-by: Vaibhav Jain > Reviewed-by: Oliver O'Halloran > --- > Change-log: > v3: > * Minor update to a code comment. [Oliver] > > v2: > * Moved the retry code from drc_pmem_bind() to papr_scm_probe() > [Oliver] > * Changed the type of variable 'rc' in drc_pmem_bind() to > int64_t. [Oliver] > --- > arch/powerpc/platforms/pseries/papr_scm.c | 15 ++++++++++++++- > 1 file changed, 14 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c > index c01a03fd3ee7..7c5e10c063a0 100644 > --- a/arch/powerpc/platforms/pseries/papr_scm.c > +++ b/arch/powerpc/platforms/pseries/papr_scm.c > @@ -43,8 +43,9 @@ struct papr_scm_priv { > static int drc_pmem_bind(struct papr_scm_priv *p) > { > unsigned long ret[PLPAR_HCALL_BUFSIZE]; > - uint64_t rc, token; > uint64_t saved = 0; > + uint64_t token; > + int64_t rc; > > /* > * When the hypervisor cannot map all the requested memory in a single > @@ -64,6 +65,10 @@ static int drc_pmem_bind(struct papr_scm_priv *p) > } while (rc == H_BUSY); > > if (rc) { > + /* H_OVERLAP needs a separate error path */ > + if (rc == H_OVERLAP) > + return -EBUSY; > + > dev_err(&p->pdev->dev, "bind err: %lld\n", rc); > return -ENXIO; > } > @@ -331,6 +336,14 @@ static int papr_scm_probe(struct platform_device *pdev) > > /* request the hypervisor to bind this region to somewhere in memory */ > rc = drc_pmem_bind(p); > + > + /* If phyp says drc memory still bound then force unbound and retry */ > + if (rc == -EBUSY) { > + dev_warn(&pdev->dev, "Retrying bind after unbinding\n"); > + drc_pmem_unbind(p); This should only be caused by kexec right? And considering kernel nor hypervisor won't change device binding details, can you check switching this to H_SCM_QUERY_BLOCK_MEM_BINDING? Will that result in faster boot? > + rc = drc_pmem_bind(p); > + } > + > if (rc) > goto err; > I am also not sure about the module reference count here. Should we increment the module reference count after a bind so that we can track failures in ubind and fail the module unload? -aneesh