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 41FC3C433DF for ; Mon, 15 Jun 2020 11:51:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EAE7F20679 for ; Mon, 15 Jun 2020 11:51:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729746AbgFOLvF (ORCPT ); Mon, 15 Jun 2020 07:51:05 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:39498 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729682AbgFOLvF (ORCPT ); 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Mon, 15 Jun 2020 11:51:00 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 05FBovbF56033282 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 15 Jun 2020 11:50:57 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8141AAE05A; Mon, 15 Jun 2020 11:50:57 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 07EE8AE045; Mon, 15 Jun 2020 11:50:57 +0000 (GMT) Received: from oc3016276355.ibm.com (unknown [9.145.1.141]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 15 Jun 2020 11:50:56 +0000 (GMT) Subject: Re: [PATCH] s390: protvirt: virtio: Refuse device without IOMMU To: Jason Wang , linux-kernel@vger.kernel.org Cc: pasic@linux.ibm.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, mst@redhat.com, cohuck@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> <467d5b58-b70c-1c45-4130-76b6e18c05af@redhat.com> <6356ba7f-afab-75e1-05ff-4a22b88c610e@linux.ibm.com> From: Pierre Morel Message-ID: <52cde80c-f33a-dbb7-d0b0-2733b3eb85c3@linux.ibm.com> Date: Mon, 15 Jun 2020 13:50:56 +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: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US 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=2020-06-15_02:2020-06-15,2020-06-15 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 bulkscore=0 mlxlogscore=999 adultscore=0 lowpriorityscore=0 mlxscore=0 malwarescore=0 spamscore=0 impostorscore=0 suspectscore=0 clxscore=1015 priorityscore=1501 cotscore=-2147483648 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006150082 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-06-15 05:01, Jason Wang wrote: > > On 2020/6/12 下午7:38, Pierre Morel wrote: >> >> >> On 2020-06-12 11:21, Pierre Morel wrote: >>> >>> >>> On 2020-06-11 05:10, Jason Wang wrote: >>>> >>>> On 2020/6/10 下午9:11, 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; >>>>> + >>>>>       /* Write the status to the host. */ >>>>>       vcdev->dma_area->status = status; >>>>>       ccw->cmd_code = CCW_CMD_WRITE_STATUS; >>>> >>>> >>>> I wonder whether we need move it to virtio core instead of ccw. >>>> >>>> I think the other memory protection technologies may suffer from >>>> this as well. >>>> >>>> Thanks >>>> >>> >>> >>> What would you think of the following, also taking into account >>> Connie's comment on where the test should be done: >>> >>> - declare a weak function in virtio.c code, returning that memory >>> protection is not in use. >>> >>> - overwrite the function in the arch code >>> >>> - call this function inside core virtio_finalize_features() and if >>> required fail if the device don't have VIRTIO_F_IOMMU_PLATFORM. > > > I think this is fine. > Thanks, I try this. Regards, Pierre -- Pierre Morel IBM Lab Boeblingen