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_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 A08ACC04AB4 for ; Fri, 17 May 2019 08:18:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D29020848 for ; Fri, 17 May 2019 08:18:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727726AbfEQISQ (ORCPT ); Fri, 17 May 2019 04:18:16 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:45432 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727386AbfEQISQ (ORCPT ); Fri, 17 May 2019 04:18:16 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4H8I3jt088195 for ; Fri, 17 May 2019 04:18:14 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2shqvpcc02-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 17 May 2019 04:18:09 -0400 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 17 May 2019 09:17:23 +0100 Received: from b06cxnps3075.portsmouth.uk.ibm.com (9.149.109.195) by e06smtp07.uk.ibm.com (192.168.101.137) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 17 May 2019 09:17:19 +0100 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x4H8HIE849741984 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 17 May 2019 08:17:18 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E9F4CAE055; Fri, 17 May 2019 08:17:17 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5D004AE053; Fri, 17 May 2019 08:17:17 +0000 (GMT) Received: from [9.145.153.112] (unknown [9.145.153.112]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 17 May 2019 08:17:17 +0000 (GMT) Reply-To: pmorel@linux.ibm.com Subject: Re: [PATCH 4/4] vfio: vfio_iommu_type1: implement VFIO_IOMMU_INFO_CAPABILITIES To: Alex Williamson Cc: sebott@linux.vnet.ibm.com, gerald.schaefer@de.ibm.com, pasic@linux.vnet.ibm.com, borntraeger@de.ibm.com, walling@linux.ibm.com, linux-s390@vger.kernel.org, iommu@lists.linux-foundation.org, joro@8bytes.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com References: <1557476555-20256-1-git-send-email-pmorel@linux.ibm.com> <1557476555-20256-5-git-send-email-pmorel@linux.ibm.com> <20190516124026.415bf671@x1.home> From: Pierre Morel Date: Fri, 17 May 2019 10:17:17 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190516124026.415bf671@x1.home> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19051708-0028-0000-0000-0000036EA8CC X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19051708-0029-0000-0000-0000242E46CE Message-Id: <29209ea1-be49-47bc-c258-6e87da055fac@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-05-17_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-1905170056 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 16/05/2019 20:40, Alex Williamson wrote: > On Fri, 10 May 2019 10:22:35 +0200 > Pierre Morel wrote: > >> We implement a capability intercafe for VFIO_IOMMU_GET_INFO and add the >> first capability: VFIO_IOMMU_INFO_CAPABILITIES. >> >> When calling the ioctl, the user must specify >> VFIO_IOMMU_INFO_CAPABILITIES to retrieve the capabilities and must check >> in the answer if capabilities are supported. >> Older kernel will not check nor set the VFIO_IOMMU_INFO_CAPABILITIES in >> the flags of vfio_iommu_type1_info. >> >> The iommu get_attr callback will be called to retrieve the specific >> attributes and fill the capabilities, VFIO_IOMMU_INFO_CAP_QFN for the >> PCI query function attributes and VFIO_IOMMU_INFO_CAP_QGRP for the >> PCI query function group. >> >> Signed-off-by: Pierre Morel >> --- >> drivers/vfio/vfio_iommu_type1.c | 95 ++++++++++++++++++++++++++++++++++++++++- >> 1 file changed, 94 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c >> index d0f731c..f7f8120 100644 >> --- a/drivers/vfio/vfio_iommu_type1.c >> +++ b/drivers/vfio/vfio_iommu_type1.c >> @@ -1658,6 +1658,70 @@ static int vfio_domains_have_iommu_cache(struct vfio_iommu *iommu) >> return ret; >> } >> >> +int vfio_iommu_type1_caps(struct vfio_iommu *iommu, struct vfio_info_cap *caps, >> + size_t size) >> +{ >> + struct vfio_domain *d; >> + struct vfio_iommu_type1_info_block *info_fn; >> + struct vfio_iommu_type1_info_block *info_grp; >> + unsigned long total_size, fn_size, grp_size; >> + int ret; >> + >> + d = list_first_entry(&iommu->domain_list, struct vfio_domain, next); >> + if (!d) >> + return -ENODEV; >> + /* The size of these capabilities are device dependent */ >> + fn_size = iommu_domain_get_attr(d->domain, >> + DOMAIN_ATTR_ZPCI_FN_SIZE, NULL); >> + if (fn_size < 0) >> + return fn_size; > > What if non-Z archs want to use this? The function is architected > specifically for this one use case, fail if any component is not there > which means it requires a re-write to add further support. If > ZPCI_FN_SIZE isn't support, move on to the next thing. yes, clear. > >> + fn_size += sizeof(struct vfio_info_cap_header); >> + total_size = fn_size; > > Here too, total_size should be initialized to zero and each section += > the size they'd like to add. thanks, clear too. > >> + >> + grp_size = iommu_domain_get_attr(d->domain, >> + DOMAIN_ATTR_ZPCI_GRP_SIZE, NULL); >> + if (grp_size < 0) >> + return grp_size; >> + grp_size += sizeof(struct vfio_info_cap_header); >> + total_size += grp_size; >> + >> + /* Tell caller to call us with a greater buffer */ >> + if (total_size > size) { >> + caps->size = total_size; >> + return 0; >> + } >> + >> + info_fn = kzalloc(fn_size, GFP_KERNEL); >> + if (!info_fn) >> + return -ENOMEM; > > Maybe fn_size was zero because we're not on Z. > >> + ret = iommu_domain_get_attr(d->domain, >> + DOMAIN_ATTR_ZPCI_FN, &info_fn->data); > > Kernel internal structures != user api. Thanks, > > Alex Thanks a lot Alex, I understand the concerns, I was too focussed on Z, I will rework this as you said: - definition of the user API and - take care that another architecture may want to use the interface. Regards, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany