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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 A99B6C433E0 for ; Tue, 16 Jun 2020 07:35:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8970A204EC for ; Tue, 16 Jun 2020 07:35:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727790AbgFPHfa (ORCPT ); Tue, 16 Jun 2020 03:35:30 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:3228 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727027AbgFPHf2 (ORCPT ); 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Tue, 16 Jun 2020 07:35:23 +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 05G7ZKKc2883926 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 16 Jun 2020 07:35:20 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A55A74C052; Tue, 16 Jun 2020 07:35:20 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3BCCD4C05C; Tue, 16 Jun 2020 07:35:20 +0000 (GMT) Received: from oc3016276355.ibm.com (unknown [9.145.26.88]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 16 Jun 2020 07:35:20 +0000 (GMT) Subject: Re: [PATCH v2 1/1] s390: virtio: let arch accept devices without IOMMU feature To: Christian Borntraeger , linux-kernel@vger.kernel.org Cc: pasic@linux.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 References: <1592224764-1258-1-git-send-email-pmorel@linux.ibm.com> <1592224764-1258-2-git-send-email-pmorel@linux.ibm.com> <74b6cf8a-d5a6-e0bf-f1c1-e453af133614@de.ibm.com> From: Pierre Morel Message-ID: Date: Tue, 16 Jun 2020 09:35:19 +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: <74b6cf8a-d5a6-e0bf-f1c1-e453af133614@de.ibm.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=2020-06-16_02:2020-06-15,2020-06-16 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 cotscore=-2147483648 impostorscore=0 lowpriorityscore=0 suspectscore=0 clxscore=1015 mlxscore=0 spamscore=0 bulkscore=0 adultscore=0 priorityscore=1501 mlxlogscore=999 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006160049 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-06-16 08:55, Christian Borntraeger wrote: > > > On 15.06.20 14:39, Pierre Morel wrote: >> An architecture protecting the guest memory against unauthorized host >> access may want to enforce VIRTIO I/O device protection through the >> use of VIRTIO_F_IOMMU_PLATFORM. >> >> Let's give a chance to the architecture to accept or not devices >> without VIRTIO_F_IOMMU_PLATFORM. >> >> Signed-off-by: Pierre Morel > > > Acked-by: Christian Borntraeger Thanks, > > Shouldnt we maybe add a pr_warn if that happens to help the admins to understand what is going on? > > Yes, Connie asked for it too, good that you remind it to me, I add it. Thanks, Pierre >> --- >> arch/s390/mm/init.c | 6 ++++++ >> drivers/virtio/virtio.c | 9 +++++++++ >> include/linux/virtio.h | 2 ++ >> 3 files changed, 17 insertions(+) >> >> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c >> index 87b2d024e75a..3f04ad09650f 100644 >> --- a/arch/s390/mm/init.c >> +++ b/arch/s390/mm/init.c >> @@ -46,6 +46,7 @@ >> #include >> #include >> #include >> +#include >> >> pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir); >> >> @@ -162,6 +163,11 @@ bool force_dma_unencrypted(struct device *dev) >> return is_prot_virt_guest(); >> } >> >> +int arch_needs_iommu_platform(struct virtio_device *dev) >> +{ >> + return is_prot_virt_guest(); >> +} >> + >> /* protected virtualization */ >> static void pv_init(void) >> { >> diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c >> index a977e32a88f2..30091089bee8 100644 >> --- a/drivers/virtio/virtio.c >> +++ b/drivers/virtio/virtio.c >> @@ -167,6 +167,11 @@ void virtio_add_status(struct virtio_device *dev, unsigned int status) >> } >> EXPORT_SYMBOL_GPL(virtio_add_status); >> >> +int __weak arch_needs_iommu_platform(struct virtio_device *dev) >> +{ >> + return 0; >> +} >> + >> 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; >> + >> virtio_add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK); >> status = dev->config->get_status(dev); >> if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) { >> diff --git a/include/linux/virtio.h b/include/linux/virtio.h >> index a493eac08393..2c46b310c38c 100644 >> --- a/include/linux/virtio.h >> +++ b/include/linux/virtio.h >> @@ -195,4 +195,6 @@ void unregister_virtio_driver(struct virtio_driver *drv); >> #define module_virtio_driver(__virtio_driver) \ >> module_driver(__virtio_driver, register_virtio_driver, \ >> unregister_virtio_driver) >> + >> +int arch_needs_iommu_platform(struct virtio_device *dev); >> #endif /* _LINUX_VIRTIO_H */ >> -- Pierre Morel IBM Lab Boeblingen