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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 A09D7C43387 for ; Fri, 18 Jan 2019 13:29:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7945D2087E for ; Fri, 18 Jan 2019 13:29:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727393AbfARN33 (ORCPT ); Fri, 18 Jan 2019 08:29:29 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:59762 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727115AbfARN33 (ORCPT ); Fri, 18 Jan 2019 08:29:29 -0500 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x0IDSB87068980 for ; Fri, 18 Jan 2019 08:29:27 -0500 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0b-001b2d01.pphosted.com with ESMTP id 2q3cxqen8x-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 18 Jan 2019 08:29:27 -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) Fri, 18 Jan 2019 13:29:22 -0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x0IDTLYA64225510 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 18 Jan 2019 13:29:21 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3A677A4054; Fri, 18 Jan 2019 13:29:21 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D1F9FA405B; Fri, 18 Jan 2019 13:29:20 +0000 (GMT) Received: from [9.145.184.65] (unknown [9.145.184.65]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 18 Jan 2019 13:29:20 +0000 (GMT) Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH v1] iommu/s390: Declare s390 iommu reserved regions To: Robin Murphy , gerald.schaefer@de.ibm.com Cc: linux-s390@vger.kernel.org, walling@linux.ibm.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, alex.williamson@redhat.com, Jean-Philippe Brucker References: <1547573850-9459-1-git-send-email-pmorel@linux.ibm.com> From: Pierre Morel Date: Fri, 18 Jan 2019 14:29:20 +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: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19011813-0012-0000-0000-000002E9C8D7 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19011813-0013-0000-0000-00002120E938 Message-Id: <3cd790d6-aa6f-e817-27ce-56d7a9b6b6e5@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-01-18_08:,, 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-1901180096 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/01/2019 14:02, Robin Murphy wrote: > On 15/01/2019 17:37, 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. >> >> The reserved region may later be retrieved from sysfs or from >> the vfio iommu internal interface. > > For this particular case, I think the best solution is to give VFIO the > ability to directly interrogate the domain geometry (which s390 appears > to set correctly already). The idea of reserved regions was really for > 'unexpected' holes inside the usable address space - using them to also > describe places that are entirely outside that address space rather > confuses things IMO. > > Furthermore, even if we *did* end up going down the route of actively > reserving addresses beyond the usable aperture, it doesn't seem sensible > for individual drivers to do it themselves when the core API already > describes the relevant information generically. > > Robin. Robin, I already posted a patch retrieving the geometry through VFIO_IOMMU_GET_INFO using a specific capability for the geometry [1], and AFAIU, Alex did not agree with this. What is different in what you propose? @Alex: I was hoping that this patch goes in your direction. What do you think? Thanks, Pierre [1]: https://lore.kernel.org/patchwork/patch/1030369/ > >> >> This seems to me related with the work Shameer has started on >> vfio_iommu_type1 so I add Alex and Shameer to the CC list. >> >> >> Pierre Morel (1): >>    iommu/s390: Declare s390 iommu reserved regions >> >>   drivers/iommu/s390-iommu.c | 29 +++++++++++++++++++++++++++++ >>   1 file changed, 29 insertions(+) >> > -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany