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 9B92AC433DF for ; Wed, 10 Jun 2020 15:27:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C3592063A for ; Wed, 10 Jun 2020 15:27:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730200AbgFJP1K (ORCPT ); Wed, 10 Jun 2020 11:27:10 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:1578 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726979AbgFJP1K (ORCPT ); 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Wed, 10 Jun 2020 15:27:05 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 05AFR2pk44171334 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 10 Jun 2020 15:27:02 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8BC6152050; Wed, 10 Jun 2020 15:27:02 +0000 (GMT) Received: from oc3016276355.ibm.com (unknown [9.145.158.19]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 1A9C15204E; Wed, 10 Jun 2020 15:27:02 +0000 (GMT) Subject: Re: [PATCH] s390: protvirt: virtio: Refuse device without IOMMU To: Cornelia Huck Cc: linux-kernel@vger.kernel.org, pasic@linux.ibm.com, 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 References: <1591794711-5915-1-git-send-email-pmorel@linux.ibm.com> <20200610152431.358fded7.cohuck@redhat.com> <54b28498-a6a7-4be2-9d2c-aef46c7fc642@linux.ibm.com> <20200610165305.1a34c548.cohuck@redhat.com> From: Pierre Morel Message-ID: <8b15139d-cd38-0861-1510-9a53530a4637@linux.ibm.com> Date: Wed, 10 Jun 2020 17:27:01 +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: <20200610165305.1a34c548.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=2020-06-10_08:2020-06-10,2020-06-10 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 malwarescore=0 spamscore=0 adultscore=0 priorityscore=1501 impostorscore=0 clxscore=1015 lowpriorityscore=0 mlxlogscore=999 suspectscore=2 bulkscore=0 cotscore=-2147483648 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006100115 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-06-10 16:53, Cornelia Huck wrote: > On Wed, 10 Jun 2020 16:37:55 +0200 > Pierre Morel wrote: > >> On 2020-06-10 15:24, Cornelia Huck wrote: >>> On Wed, 10 Jun 2020 15:11:51 +0200 >>> Pierre Morel wrote: >>> >>>> Protected Virtualisation protects the memory of the guest and >>>> do not allow a the host to access all of its memory. >>>> >>>> Let's refuse a VIRTIO device which does not use IOMMU >>>> protected access. >>>> >>>> Signed-off-by: Pierre Morel >>>> --- >>>> drivers/s390/virtio/virtio_ccw.c | 5 +++++ >>>> 1 file changed, 5 insertions(+) >>>> >>>> diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c >>>> index 5730572b52cd..06ffbc96587a 100644 >>>> --- a/drivers/s390/virtio/virtio_ccw.c >>>> +++ b/drivers/s390/virtio/virtio_ccw.c >>>> @@ -986,6 +986,11 @@ static void virtio_ccw_set_status(struct virtio_device *vdev, u8 status) >>>> if (!ccw) >>>> return; >>>> >>>> + /* Protected Virtualisation guest needs IOMMU */ >>>> + if (is_prot_virt_guest() && >>>> + !__virtio_test_bit(vdev, VIRTIO_F_IOMMU_PLATFORM)) >>>> + status &= ~VIRTIO_CONFIG_S_FEATURES_OK; >>>> + >>> >>> set_status seems like an odd place to look at features; shouldn't that >>> rather be done in finalize_features? >> >> Right, looks better to me too. >> What about: >> >> >> >> diff --git a/drivers/s390/virtio/virtio_ccw.c >> b/drivers/s390/virtio/virtio_ccw.c >> index 06ffbc96587a..227676297ea0 100644 >> --- a/drivers/s390/virtio/virtio_ccw.c >> +++ b/drivers/s390/virtio/virtio_ccw.c >> @@ -833,6 +833,11 @@ static int virtio_ccw_finalize_features(struct >> virtio_device *vdev) >> ret = -ENOMEM; >> goto out_free; >> } >> + >> + if (is_prot_virt_guest() && >> + !__virtio_test_bit(vdev, VIRTIO_F_IOMMU_PLATFORM)) > > Add a comment, and (maybe) a message? > > Otherwise, I think this is fine, as it should fail the probe, which is > what we want. yes right a message is needed. and I extend a little the comment I had before. thanks Regards, Pierre -- Pierre Morel IBM Lab Boeblingen