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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 30168C43387 for ; Wed, 16 Jan 2019 09:34:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 05CB120840 for ; Wed, 16 Jan 2019 09:34:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388916AbfAPJeB (ORCPT ); Wed, 16 Jan 2019 04:34:01 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:60536 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388767AbfAPJeA (ORCPT ); Wed, 16 Jan 2019 04:34:00 -0500 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id x0G9OF5U110238 for ; Wed, 16 Jan 2019 04:33:59 -0500 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2q1ytjepgp-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 16 Jan 2019 04:33:59 -0500 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 16 Jan 2019 09:33:54 -0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x0G9XrAc50659582 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 16 Jan 2019 09:33:53 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 57F3C11C04A; Wed, 16 Jan 2019 09:33:53 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D51E511C050; Wed, 16 Jan 2019 09:33:52 +0000 (GMT) Received: from [9.152.224.140] (unknown [9.152.224.140]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 16 Jan 2019 09:33:52 +0000 (GMT) Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH v1] iommu/s390: Declare s390 iommu reserved regions To: Gerald Schaefer Cc: joro@8bytes.org, linux-s390@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, alex.williamson@redhat.com, shameerali.kolothum.thodi@huawei.com, walling@linux.ibm.com References: <1547573850-9459-1-git-send-email-pmorel@linux.ibm.com> <1547573850-9459-2-git-send-email-pmorel@linux.ibm.com> <20190115203335.111bfcdc@thinkpad> From: Pierre Morel Date: Wed, 16 Jan 2019 10:33:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190115203335.111bfcdc@thinkpad> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19011609-0012-0000-0000-000002E8B5D0 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19011609-0013-0000-0000-0000211FCCFB Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-01-16_04:,, 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-1901160080 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/01/2019 20:33, Gerald Schaefer wrote: > On Tue, 15 Jan 2019 18:37:30 +0100 > Pierre Morel wrote: > >> The s390 iommu can only allow DMA transactions between the zPCI device >> entries start_dma and end_dma. >> >> Let's declare the regions before start_dma and after end_dma as >> reserved regions using the appropriate callback in iommu_ops. >> >> Signed-off-by: Pierre Morel >> --- >> drivers/iommu/s390-iommu.c | 29 +++++++++++++++++++++++++++++ >> 1 file changed, 29 insertions(+) >> >> diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c >> index 22d4db3..5ca91a1 100644 >> --- a/drivers/iommu/s390-iommu.c >> +++ b/drivers/iommu/s390-iommu.c >> @@ -363,6 +363,33 @@ void zpci_destroy_iommu(struct zpci_dev *zdev) >> iommu_device_sysfs_remove(&zdev->iommu_dev); >> } >> >> +static void s390_get_resv_regions(struct device *dev, struct list_head *head) >> +{ >> + struct iommu_resv_region *region; >> + struct zpci_dev *zdev = to_pci_dev(dev)->sysdata; >> + >> + region = iommu_alloc_resv_region(0, zdev->start_dma, >> + 0, IOMMU_RESV_RESERVED); >> + if (!region) >> + return; >> + list_add_tail(®ion->list, head); >> + >> + region = iommu_alloc_resv_region(zdev->end_dma + 1, >> + ~0UL - zdev->end_dma, >> + 0, IOMMU_RESV_RESERVED); > > Can you guarantee that start_dma will never be 0 and end_dma never ~0UL, > even with future HW? > > In any of these cases, your code would reserve strange ranges, and sysfs > would report broken reserved ranges. > > Maybe add a check for start_dma > 0 and end_dma < ULONG_MAX? Yes, thanks. > >> + if (!region) >> + return; >> + list_add_tail(®ion->list, head); >> +} >> + >> +static void s390_put_resv_regions(struct device *dev, struct list_head *head) >> +{ >> + struct iommu_resv_region *entry, *next; >> + >> + list_for_each_entry_safe(entry, next, head, list) >> + kfree(entry); >> +} > > It looks very wrong that there is no matching list_del() for the previous > list_add_tail(). However, it seems to be done like this everywhere else, > and the calling functions (currently) only use temporary list_heads as > far as I can see, so I guess it should be OK (for now). > > Still, a list_del() would be nice :-) hum. right. > >> + >> static const struct iommu_ops s390_iommu_ops = { >> .capable = s390_iommu_capable, >> .domain_alloc = s390_domain_alloc, >> @@ -376,6 +403,8 @@ static const struct iommu_ops s390_iommu_ops = { >> .remove_device = s390_iommu_remove_device, >> .device_group = generic_device_group, >> .pgsize_bitmap = S390_IOMMU_PGSIZES, >> + .get_resv_regions = s390_get_resv_regions, >> + .put_resv_regions = s390_put_resv_regions, >> }; >> >> static int __init s390_iommu_init(void) > > With the start/end_dma issue addressed (if necessary): > Acked-by: Gerald Schaefer > Thanks. Regards, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany