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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 1323FC433DF for ; Tue, 16 Jun 2020 11:58:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EF1AF206F1 for ; Tue, 16 Jun 2020 11:58:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728728AbgFPL6D (ORCPT ); Tue, 16 Jun 2020 07:58:03 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:45776 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728481AbgFPL6D (ORCPT ); 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Tue, 16 Jun 2020 11:57:53 +0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 05GBvoDl60555284 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 16 Jun 2020 11:57:50 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A55BC4C046; Tue, 16 Jun 2020 11:57:50 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EC4D14C040; Tue, 16 Jun 2020 11:57:49 +0000 (GMT) Received: from oc2783563651 (unknown [9.145.56.227]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 16 Jun 2020 11:57:49 +0000 (GMT) Date: Tue, 16 Jun 2020 13:57:26 +0200 From: Halil Pasic To: Pierre Morel Cc: linux-kernel@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, mst@redhat.com, jasowang@redhat.com, cohuck@redhat.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org, virtualization@lists.linux-foundation.org, thomas.lendacky@amd.com, David Gibson , Ram Pai , Heiko Carstens , Vasily Gorbik Subject: Re: [PATCH v2 1/1] s390: virtio: let arch accept devices without IOMMU feature Message-ID: <20200616135726.04fa8314.pasic@linux.ibm.com> In-Reply-To: References: <1592224764-1258-1-git-send-email-pmorel@linux.ibm.com> <1592224764-1258-2-git-send-email-pmorel@linux.ibm.com> <20200616115202.0285aa08.pasic@linux.ibm.com> Organization: IBM X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216,18.0.687 definitions=2020-06-16_04:2020-06-15,2020-06-16 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 bulkscore=0 impostorscore=0 suspectscore=0 priorityscore=1501 malwarescore=0 mlxlogscore=999 adultscore=0 spamscore=0 mlxscore=0 clxscore=1015 cotscore=-2147483648 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006160084 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 16 Jun 2020 12:52:50 +0200 Pierre Morel wrote: > >> int virtio_finalize_features(struct virtio_device *dev) > >> { > >> int ret = dev->config->finalize_features(dev); > >> @@ -179,6 +184,10 @@ int virtio_finalize_features(struct virtio_device *dev) > >> if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) > >> return 0; > >> > >> + if (arch_needs_iommu_platform(dev) && > >> + !virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) > >> + return -EIO; > >> + > > > > Why EIO? > > Because I/O can not occur correctly? > I am open to suggestions. We use -ENODEV if feature when the device rejects the features we tried to negotiate (see virtio_finalize_features()) and -EINVAL when the F_VERSION_1 and the virtio-ccw revision ain't coherent (in virtio_ccw_finalize_features()). Any of those seems more fitting that EIO to me. BTW does the error code itself matter in any way, or is it just OK vs some error? Regards, Halil