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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 ED3F0C433E3 for ; Mon, 29 Jun 2020 18:49:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBE69204EC for ; Mon, 29 Jun 2020 18:49:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729357AbgF2Stu (ORCPT ); Mon, 29 Jun 2020 14:49:50 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:20869 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729180AbgF2Stl (ORCPT ); Mon, 29 Jun 2020 14:49:41 -0400 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 05TDDoaj110929; Mon, 29 Jun 2020 09:14:22 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 31ycg2j394-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 29 Jun 2020 09:14:22 -0400 Received: from m0098419.ppops.net (m0098419.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 05TD5mQt066402; Mon, 29 Jun 2020 09:14:21 -0400 Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0b-001b2d01.pphosted.com with ESMTP id 31ycg2j386-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 29 Jun 2020 09:14:21 -0400 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 05TDB5tJ007572; Mon, 29 Jun 2020 13:14:19 GMT Received: from b06avi18626390.portsmouth.uk.ibm.com (b06avi18626390.portsmouth.uk.ibm.com [9.149.26.192]) by ppma03ams.nl.ibm.com with ESMTP id 31wwr8ac50-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 29 Jun 2020 13:14:19 +0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 05TDCvaS59965942 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 29 Jun 2020 13:12:57 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DC98A11C04C; Mon, 29 Jun 2020 13:14:16 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 11FC011C058; Mon, 29 Jun 2020 13:14:05 +0000 (GMT) Received: from oc3016276355.ibm.com (unknown [9.145.28.234]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 29 Jun 2020 13:14:04 +0000 (GMT) Subject: Re: [PATCH v3 1/1] s390: virtio: let arch accept devices without IOMMU feature To: Cornelia Huck , Halil Pasic Cc: linux-kernel@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, mst@redhat.com, jasowang@redhat.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, virtualization@lists.linux-foundation.org, thomas.lendacky@amd.com, david@gibson.dropbear.id.au, linuxram@us.ibm.com, heiko.carstens@de.ibm.com, gor@linux.ibm.com References: <1592390637-17441-1-git-send-email-pmorel@linux.ibm.com> <1592390637-17441-2-git-send-email-pmorel@linux.ibm.com> <20200618002956.5f179de4.pasic@linux.ibm.com> <20200619112051.74babdb1.cohuck@redhat.com> From: Pierre Morel Message-ID: <7fe6e9ab-fd5a-3f92-1f3a-f9e6805d3730@linux.ibm.com> Date: Mon, 29 Jun 2020 15:14:04 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200619112051.74babdb1.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216,18.0.687 definitions=2020-06-29_11:2020-06-29,2020-06-29 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 bulkscore=0 mlxlogscore=999 priorityscore=1501 suspectscore=0 clxscore=1015 adultscore=0 malwarescore=0 cotscore=-2147483648 spamscore=0 impostorscore=0 lowpriorityscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006290089 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2020-06-19 11:20, Cornelia Huck wrote: > On Thu, 18 Jun 2020 00:29:56 +0200 > Halil Pasic wrote: > >> On Wed, 17 Jun 2020 12:43:57 +0200 >> Pierre Morel wrote: ... >> >> But since this can be rewritten any time, let's go with the option >> people already agree with, instead of more discussion. > > Yes, there's nothing wrong with the patch as-is. > > Acked-by: Cornelia Huck Thanks, > > Which tree should this go through? Virtio? s390? > >> >> Just another question. Do we want this backported? Do we need cc stable? > > It does change behaviour of virtio-ccw devices; but then, it only > fences off configurations that would not have worked anyway. > Distributions should probably pick this; but I do not consider it > strictly a "fix" (more a mitigation for broken configurations), so I'm > not sure whether stable applies. > >> [..] >> >> >>> int virtio_finalize_features(struct virtio_device *dev) >>> { >>> int ret = dev->config->finalize_features(dev); >>> @@ -179,6 +194,13 @@ int virtio_finalize_features(struct virtio_device *dev) >>> if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) >>> return 0; >>> >>> + if (arch_needs_virtio_iommu_platform(dev) && >>> + !virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { >>> + dev_warn(&dev->dev, >>> + "virtio: device must provide VIRTIO_F_IOMMU_PLATFORM\n"); >> >> I'm not sure, divulging the current Linux name of this feature bit is a >> good idea, but if everybody else is fine with this, I don't care that > > Not sure if that feature name will ever change, as it is exported in > headers. At most, we might want to add the new ACCESS_PLATFORM define > and keep the old one, but that would still mean some churn. > >> much. An alternative would be: >> "virtio: device falsely claims to have full access to the memory, >> aborting the device" > > "virtio: device does not work with limited memory access" ? > > But no issue with keeping the current message. > If it is OK, I would like to specify that the arch is responsible to accept or not the device. The reason why the device is not accepted without IOMMU_PLATFORM is arch specific. Regards, Pierre -- Pierre Morel IBM Lab Boeblingen