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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C07D1C433EF for ; Mon, 7 Feb 2022 15:51:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240053AbiBGPuu (ORCPT ); Mon, 7 Feb 2022 10:50:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1384530AbiBGPnl (ORCPT ); Mon, 7 Feb 2022 10:43:41 -0500 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B2FEC0401C1; Mon, 7 Feb 2022 07:43:41 -0800 (PST) Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 217F4F8r019786; Mon, 7 Feb 2022 15:43:40 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=pp1; bh=GY/qxCBOtnM10f+Y/FEZFQS14z6BzRd4HNAeuIMFpaI=; b=s+NORjrMNaWNjg7eeW2DkCRj9Mw6gVATcGhgrkO1rMIqE71aetO4Kykf6HiewaCGeGmG JWB3KKH0OqNBMu052Yv68UMIx/4Jdas+MEpsYLWfjHHZyAy7jJJoLgvvBChjBGzn/cO2 ieF80nnID7vThyphLoKt+dqx7EFxHbrP5Usu9X4fxSHy7naGV5VjUxvrRYYWfEmSm3yV wBYaQcpk/6S3r8f6fFIuOCY141y/0BnOLlzdnDprEfMWajpRPBvG1QVXLY1vmpZzhTxN tAZ7Ej59nIU7EIKHsqy0lsTZihq8XFqdwFywj8x6t0+nX95MdspeZoUmnjq3TwoOPbxn 8w== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 3e22kq03ue-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 07 Feb 2022 15:43:40 +0000 Received: from m0098419.ppops.net (m0098419.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 217F8bWe019937; Mon, 7 Feb 2022 15:43:39 GMT Received: from ppma01wdc.us.ibm.com (fd.55.37a9.ip4.static.sl-reverse.com [169.55.85.253]) by mx0b-001b2d01.pphosted.com with ESMTP id 3e22kq03u3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 07 Feb 2022 15:43:39 +0000 Received: from pps.filterd (ppma01wdc.us.ibm.com [127.0.0.1]) by ppma01wdc.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 217FXfse008368; Mon, 7 Feb 2022 15:43:39 GMT Received: from b03cxnp08026.gho.boulder.ibm.com (b03cxnp08026.gho.boulder.ibm.com [9.17.130.18]) by ppma01wdc.us.ibm.com with ESMTP id 3e1gv9r5pp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 07 Feb 2022 15:43:38 +0000 Received: from b03ledav003.gho.boulder.ibm.com (b03ledav003.gho.boulder.ibm.com [9.17.130.234]) by b03cxnp08026.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 217Fhbwx17891674 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 7 Feb 2022 15:43:37 GMT Received: from b03ledav003.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 60B1F6A051; Mon, 7 Feb 2022 15:43:37 +0000 (GMT) Received: from b03ledav003.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 69B516A054; Mon, 7 Feb 2022 15:43:35 +0000 (GMT) Received: from [9.211.136.120] (unknown [9.211.136.120]) by b03ledav003.gho.boulder.ibm.com (Postfix) with ESMTP; Mon, 7 Feb 2022 15:43:35 +0000 (GMT) Message-ID: <1ff6e06c-e563-2b9c-3196-542fed7df0f9@linux.ibm.com> Date: Mon, 7 Feb 2022 10:43:34 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v3 14/30] vfio/pci: re-introduce CONFIG_VFIO_PCI_ZDEV Content-Language: en-US To: Cornelia Huck , linux-s390@vger.kernel.org Cc: alex.williamson@redhat.com, schnelle@linux.ibm.com, farman@linux.ibm.com, pmorel@linux.ibm.com, borntraeger@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, gerald.schaefer@linux.ibm.com, agordeev@linux.ibm.com, frankja@linux.ibm.com, david@redhat.com, imbrenda@linux.ibm.com, vneethv@linux.ibm.com, oberpar@linux.ibm.com, freude@linux.ibm.com, thuth@redhat.com, pasic@linux.ibm.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20220204211536.321475-1-mjrosato@linux.ibm.com> <20220204211536.321475-15-mjrosato@linux.ibm.com> <87czjzvztw.fsf@redhat.com> From: Matthew Rosato In-Reply-To: <87czjzvztw.fsf@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: NZsE0Lv1I4b2ew2YEwRoh9neRiXU6OrX X-Proofpoint-ORIG-GUID: RPEb0Y0ii7lfDXM54cp9IFrLoluoTyzO X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.62.513 definitions=2022-02-07_06,2022-02-07_02,2021-12-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 priorityscore=1501 bulkscore=0 spamscore=0 impostorscore=0 suspectscore=0 mlxlogscore=999 lowpriorityscore=0 adultscore=0 malwarescore=0 mlxscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2202070099 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/7/22 3:35 AM, Cornelia Huck wrote: > On Fri, Feb 04 2022, Matthew Rosato wrote: > >> This was previously removed as unnecessary; while that was true, subsequent >> changes will make KVM an additional required component for vfio-pci-zdev. >> Let's re-introduce CONFIG_VFIO_PCI_ZDEV as now there is actually a reason >> to say 'n' for it (when not planning to CONFIG_KVM). > > Hm... can the file be split into parts that depend on KVM and parts that > don't? Does anybody ever use vfio-pci on a non-kvm s390 system? > It is possible to split out most of the prior CLP/ vfio capability work (but it would not be a totally clean split, zpci_group_cap for example would need to have an inline ifdef since it references a KVM structure) -- I suspect we'll see more of that in the future. I'm not totally sure if there's value in the information being provided today -- this CLP information was all added specifically with userspace->guest delivery in mind. And to answer your other question, I'm not directly aware of non-kvm vfio-pci usage on s390 today; but that doesn't mean there isn't any or won't be in the future of course. With this series, you could CONFIG_KVM=n + CONFIG_VFIO_PCI=y|m and you'll get the standard vfio-pci support but never any vfio-pci-zdev extension. If we wanted to provide everything we can where KVM isn't strictly required, then let's look at what a split would look like: With or without KVM: zcpi_base_cap zpci_group_cap (with an inline ifdef for KVM [1]) zpci_util_cap zpci_pfip_cap vfio_pci_info_zdev_add_caps vfio_pci_zdev_open (ifdef, just return when !KVM [1]) vfio_pci_zdev_release (ifdef, just return when !KVM [1]) KVM only: vfio_pci_zdev_feat_interp vfio_pci_zdev_feat_aif vfio_pci_zdev_feat_ioat vfio_pci_zdev_group_notifier I suppose such a split has the benefit of flexibility / future-proofing... should a non-kvm use case arrive in the future for s390 and we find we need some s390-specific handling, we're still building vfio-pci-zdev into vfio-pci by default and can just extend that. [1] In this case I would propose renaming CONFIG_VFIO_PCI_ZDEV as we would once again always be building some part of vfio-pci-zdev with vfio-pci on s390 -- maybe something like CONFIG_VFIO_PCI_ZDEV_KVM (wow that's a mouthful) and then use this setting to check "KVM" in my above split. Since this setting will imply PCI, VFIO_PCI and KVM, we can then s/CONFIG_VFIO_PCI_ZDEV/CONFIG_VFIO_PCI_ZDEV_KVM/ for the rest of the series (to continue covering cases like we build KVM but not pci, or not vfio-pci) How does that sound?