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=-12.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, 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 5A708C433DF for ; Thu, 30 Jul 2020 11:32:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3FE7E2074B for ; Thu, 30 Jul 2020 11:32:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727808AbgG3LcV (ORCPT ); Thu, 30 Jul 2020 07:32:21 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:3160 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726615AbgG3LcV (ORCPT ); Thu, 30 Jul 2020 07:32:21 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 06UBW5MM026230; Thu, 30 Jul 2020 07:32:12 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 32kv5rj4q2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 30 Jul 2020 07:32:11 -0400 Received: from m0098417.ppops.net (m0098417.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 06UBW9cu026634; Thu, 30 Jul 2020 07:32:11 -0400 Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0a-001b2d01.pphosted.com with ESMTP id 32kv5rj4hc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 30 Jul 2020 07:32:11 -0400 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 06UBKROE016839; Thu, 30 Jul 2020 11:31:56 GMT Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by ppma06ams.nl.ibm.com with ESMTP id 32gcqgp3wr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 30 Jul 2020 11:31:56 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 06UBVrQT9568562 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 30 Jul 2020 11:31:53 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id ACC43520C9; Thu, 30 Jul 2020 11:31:51 +0000 (GMT) Received: from oc3016276355.ibm.com (unknown [9.145.51.62]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 893CB52133; Thu, 30 Jul 2020 11:31:20 +0000 (GMT) Subject: Re: [PATCH v7 2/2] s390: virtio: PV needs VIRTIO I/O device protection To: "Michael S. Tsirkin" , Jason Wang Cc: linux-kernel@vger.kernel.org, pasic@linux.ibm.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, cohuck@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, hca@linux.ibm.com, gor@linux.ibm.com References: <1594801869-13365-1-git-send-email-pmorel@linux.ibm.com> <1594801869-13365-3-git-send-email-pmorel@linux.ibm.com> <20200715054807-mutt-send-email-mst@kernel.org> <20200715074917-mutt-send-email-mst@kernel.org> From: Pierre Morel Message-ID: Date: Thu, 30 Jul 2020 13:31:20 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200715074917-mutt-send-email-mst@kernel.org> 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=2.50.10434:6.0.235,18.0.687 definitions=2020-07-30_09:2020-07-30,2020-07-30 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 mlxlogscore=999 impostorscore=0 spamscore=0 priorityscore=1501 malwarescore=0 suspectscore=0 lowpriorityscore=0 mlxscore=0 bulkscore=0 adultscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007300082 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org gentle ping. On 2020-07-15 13:51, Michael S. Tsirkin wrote: > On Wed, Jul 15, 2020 at 06:16:59PM +0800, Jason Wang wrote: >> >> On 2020/7/15 下午5:50, Michael S. Tsirkin wrote: >>> On Wed, Jul 15, 2020 at 10:31:09AM +0200, Pierre Morel wrote: >>>> If protected virtualization is active on s390, the virtio queues are >>>> not accessible to the host, unless VIRTIO_F_IOMMU_PLATFORM has been >>>> negotiated. Use the new arch_validate_virtio_features() interface to >>>> fail probe if that's not the case, preventing a host error on access >>>> attempt. >>>> >>>> Signed-off-by: Pierre Morel >>>> Reviewed-by: Cornelia Huck >>>> Acked-by: Halil Pasic >>>> Acked-by: Christian Borntraeger >>>> --- >>>> arch/s390/mm/init.c | 28 ++++++++++++++++++++++++++++ >>>> 1 file changed, 28 insertions(+) >>>> >>>> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c >>>> index 6dc7c3b60ef6..d39af6554d4f 100644 >>>> --- a/arch/s390/mm/init.c >>>> +++ b/arch/s390/mm/init.c >>>> @@ -45,6 +45,7 @@ >>>> #include >>>> #include >>>> #include >>>> +#include >>>> pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir); >>>> @@ -161,6 +162,33 @@ bool force_dma_unencrypted(struct device *dev) >>>> return is_prot_virt_guest(); >>>> } >>>> +/* >>>> + * arch_validate_virtio_features >>>> + * @dev: the VIRTIO device being added >>>> + * >>>> + * Return an error if required features are missing on a guest running >>>> + * with protected virtualization. >>>> + */ >>>> +int arch_validate_virtio_features(struct virtio_device *dev) >>>> +{ >>>> + if (!is_prot_virt_guest()) >>>> + return 0; >>>> + >>>> + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) { >>>> + dev_warn(&dev->dev, >>>> + "legacy virtio not supported with protected virtualization\n"); >>>> + return -ENODEV; >>>> + } >>>> + >>>> + if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) { >>>> + dev_warn(&dev->dev, >>>> + "support for limited memory access required for protected virtualization\n"); >>>> + return -ENODEV; >>>> + } >>>> + >>>> + return 0; >>>> +} >>>> + >>>> /* protected virtualization */ >>>> static void pv_init(void) >>>> { >>> What bothers me here is that arch code depends on virtio now. >>> It works even with a modular virtio when functions are inline, >>> but it seems fragile: e.g. it breaks virtio as an out of tree module, >>> since layout of struct virtio_device can change. >> >> >> The code was only called from virtio.c so it should be fine. >> >> And my understanding is that we don't need to care about the kABI issue >> during upstream development? >> >> Thanks > > No, but so far it has been convenient at least for me, for development, > to just be able to unload all of virtio and load a different version. > > >> >>> >>> I'm not sure what to do with this yet, will try to think about it >>> over the weekend. Thanks! >>> >>> >>>> -- >>>> 2.25.1 > -- Pierre Morel IBM Lab Boeblingen