From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756022AbeDQQTB (ORCPT ); Tue, 17 Apr 2018 12:19:01 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:41374 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755718AbeDQQS7 (ORCPT ); Tue, 17 Apr 2018 12:18:59 -0400 Subject: Re: [PATCH v4 13/15] KVM: s390: configure the guest's AP devices To: Tony Krowiak , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: freude@de.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, borntraeger@de.ibm.com, cohuck@redhat.com, kwankhede@nvidia.com, bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com, alex.williamson@redhat.com, alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com, jjherne@linux.vnet.ibm.com, thuth@redhat.com, pasic@linux.vnet.ibm.com, berrange@redhat.com, fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com References: <1523827345-11600-1-git-send-email-akrowiak@linux.vnet.ibm.com> <1523827345-11600-14-git-send-email-akrowiak@linux.vnet.ibm.com> <2e7387b9-ceb4-cdca-56ac-f5344084e10a@linux.vnet.ibm.com> From: Pierre Morel Date: Tue, 17 Apr 2018 18:18:50 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18041716-0040-0000-0000-000004300941 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18041716-0041-0000-0000-0000263414FA Message-Id: <105bce81-9359-6096-88ce-01ec1aef523e@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-17_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804170143 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/04/2018 18:08, Tony Krowiak wrote: > On 04/16/2018 09:05 AM, Pierre Morel wrote: >> On 15/04/2018 23:22, Tony Krowiak wrote: >>> Registers a group notifier during the open of the mediated >>> matrix device to get information on KVM presence through the >>> VFIO_GROUP_NOTIFY_SET_KVM event. When notified, the pointer >>> to the kvm structure is saved inside the mediated matrix >>> device. Once the VFIO AP device driver has access to KVM, >>> access to the APs can be configured for the guest. >>> >>> Access to APs is configured when the file descriptor for the >>> mediated matrix device is opened by userspace. The items to be >>> configured are: >>> >>> 1. The ECA.28 bit in the SIE state description determines whether >>>     AP instructions are interpreted by the hardware or intercepted. >>>     The VFIO AP device driver relies interpretive execution of >>>     AP instructions so the ECA.28 bit will be set >>> >>> 2. Guest access to AP adapters, usage domains and control domains >>>     is controlled by three bit masks referenced from the >>>     Crypto Control Block (CRYCB) referenced from the guest's SIE state >>>     description: >>> >>>     * The AP Mask (APM) controls access to the AP adapters. Each bit >>>       in the APM represents an adapter number - from most significant >>>       to least significant bit - from 0 to 255. The bits in the APM >>>       are set according to the adapter numbers assigned to the mediated >>>       matrix device via its 'assign_adapter' sysfs attribute file. >>> >>>     * The AP Queue (AQM) controls access to the AP queues. Each bit >>>       in the AQM represents an AP queue index - from most significant >>>       to least significant bit - from 0 to 255. A queue index >>> references >>>       a specific domain and is synonymous with the domian number. The >>>       bits in the AQM are set according to the domain numbers assigned >>>       to the mediated matrix device via its 'assign_domain' sysfs >>>       attribute file. >>> >>>     * The AP Domain Mask (ADM) controls access to the AP control >>> domains. >>>       Each bit in the ADM represents a control domain - from most >>>       significant to least significant bit - from 0-255. The >>>       bits in the ADM are set according to the domain numbers assigned >>>       to the mediated matrix device via its 'assign_control_domain' >>>       sysfs attribute file. >>> >>> Signed-off-by: Tony Krowiak >>> --- >>>   drivers/s390/crypto/vfio_ap_ops.c     |   50 >>> +++++++++++++++++++++++++++++++++ >>>   drivers/s390/crypto/vfio_ap_private.h |    2 + >>>   2 files changed, 52 insertions(+), 0 deletions(-) >>> >>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c >>> b/drivers/s390/crypto/vfio_ap_ops.c >>> index bc2b05e..e3ff5ab 100644 >>> --- a/drivers/s390/crypto/vfio_ap_ops.c >>> +++ b/drivers/s390/crypto/vfio_ap_ops.c >>> @@ -53,6 +53,54 @@ static int vfio_ap_mdev_remove(struct mdev_device >>> *mdev) >>>       return 0; >>>   } >>> >>> +static int vfio_ap_mdev_group_notifier(struct notifier_block *nb, >>> +                       unsigned long action, void *data) >>> +{ >>> +    struct ap_matrix_mdev *matrix_mdev; >>> + >>> +    if (action == VFIO_GROUP_NOTIFY_SET_KVM) { >>> +        matrix_mdev = container_of(nb, struct ap_matrix_mdev, >>> +                       group_notifier); >>> +        matrix_mdev->kvm = data; >>> +    } >>> + >>> +    return NOTIFY_OK; >>> +} >>> + >>> +static int vfio_ap_mdev_open(struct mdev_device *mdev) >>> +{ >>> +    struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev); >>> +    unsigned long events; >>> +    int ret; >>> + >>> +    matrix_mdev->group_notifier.notifier_call = >>> vfio_ap_mdev_group_notifier; >>> +    events = VFIO_GROUP_NOTIFY_SET_KVM; >>> + >>> +    ret = vfio_register_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, >>> +                     &events, &matrix_mdev->group_notifier); >>> +    if (ret) >>> +        return ret; >>> + >>> +    ret = kvm_ap_interpret_instructions(matrix_mdev->kvm, true); >> >> Do you need this call ? >> apie is always enabled in KVM if AP instructions are available. > > I suppose we don't, in which case we don't need the > kvm_ap_interpret_instructions() > function either ... at least not until we implement interception. > >> >> >> Setting or not the interpretation is done for the VM in a all. >> It is not the right place to do it here since open is device dependent. > > As I stated above, at this time we probably do not need this, however; > that will not always be the case. The setting is and always will be > for the > VM in all - unless the architecture changes - because it is controlled > by a > single bit (ECA.28). If you recall, I originally set interpretation in > the > vfio_ap device driver when notified of the VFIO_GROUP_NOTIFY_SET_KVM > event. > I believe ultimately that it is the device driver that should set the > value > for apie. > > > >> >> >> Or we only have one device in the VM at a time. >> In this case, shouldn't we make it official by returning -EEXIST for >> the second call? > > We do allow only one vfio-ap device at a time. QEMU will allow only > one vfio-ap device > to be configured for a guest. Should we also put a check in here? QEMU is not the only possible user of this interface. > >> >> >> >>> +    if (ret) >>> +        return ret; >>> + >>> +    ret = kvm_ap_configure_matrix(matrix_mdev->kvm, >>> +                      matrix_mdev->matrix); >>> + >>> +    return ret; >>> +} >>> + >>> +static void vfio_ap_mdev_release(struct mdev_device *mdev) >>> +{ >>> +    struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev); >>> + >>> +    kvm_ap_deconfigure_matrix(matrix_mdev->kvm); >>> +    kvm_ap_interpret_instructions(matrix_mdev->kvm, false); >> >> This call clears the apie in KVM. >> This is only OK if we have a single device present until the end of >> the VM, >> otherwise AP instructions in the guest will fail after the release >> until the end of the VM >> or until a new device is plugged. > > See Message ID: > <1523819244-29954-5-git-send-email-akrowiak@linux.vnet.ibm.com> on the > qemu mailing list. There will be only one vfio-ap device allowed for > the MVP model. dito. Anyone can write a userland application using this interface. > >> >> >> >>> + vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, >>> +                 &matrix_mdev->group_notifier); >>> +} >>> + >>>   static ssize_t name_show(struct kobject *kobj, struct device *dev, >>> char *buf) >>>   { >>>       return sprintf(buf, "%s\n", VFIO_AP_MDEV_NAME_HWVIRT); >>> @@ -754,6 +802,8 @@ static ssize_t matrix_show(struct device *dev, >>> struct device_attribute *attr, >>>       .mdev_attr_groups    = vfio_ap_mdev_attr_groups, >>>       .create            = vfio_ap_mdev_create, >>>       .remove            = vfio_ap_mdev_remove, >>> +    .open            = vfio_ap_mdev_open, >>> +    .release        = vfio_ap_mdev_release, >>>   }; >>> >>>   int vfio_ap_mdev_register(struct ap_matrix *ap_matrix) >>> diff --git a/drivers/s390/crypto/vfio_ap_private.h >>> b/drivers/s390/crypto/vfio_ap_private.h >>> index f248faf..48e2806 100644 >>> --- a/drivers/s390/crypto/vfio_ap_private.h >>> +++ b/drivers/s390/crypto/vfio_ap_private.h >>> @@ -31,6 +31,8 @@ struct ap_matrix { >>> >>>   struct ap_matrix_mdev { >>>       struct kvm_ap_matrix *matrix; >>> +    struct notifier_block group_notifier; >>> +    struct kvm *kvm; >>>   }; >>> >>>   static inline struct ap_matrix *to_ap_matrix(struct device *dev) >> >> > -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany