From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Krowiak Subject: Re: [PATCH v6 3/7] s390: ap: setup relation betwen KVM and mediated device Date: Thu, 28 Mar 2019 12:12:17 -0400 Message-ID: <1ea236d1-ca0b-03c0-3699-0c0deb435785@linux.ibm.com> References: <1553265828-27823-1-git-send-email-pmorel@linux.ibm.com> <1553265828-27823-4-git-send-email-pmorel@linux.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: alex.williamson@redhat.com, cohuck@redhat.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, frankja@linux.ibm.com, pasic@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com, mimu@linux.ibm.com To: Pierre Morel , borntraeger@de.ibm.com Return-path: In-Reply-To: <1553265828-27823-4-git-send-email-pmorel@linux.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 3/22/19 10:43 AM, Pierre Morel wrote: > When the mediated device is open we setup the relation with KVM unset it > when the mediated device is released. s/open we setup/open, we set up/ s/with KVM unset/with KVM and unset/ > > We lock the matrix mediated device to avoid any change until the > open is done. > We make sure that KVM is present when opening the mediated device > otherwise we return an error. s/mediated device/mediated device,/ > > Increase kvm's refcount to ensure the KVM structures are still available > during the use of the mediated device by the guest. > > Signed-off-by: Pierre Morel > --- > drivers/s390/crypto/vfio_ap_ops.c | 143 +++++++++++++++++++++----------------- > 1 file changed, 79 insertions(+), 64 deletions(-) > > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c > index 77f7bac..bdb36e0 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -787,74 +787,24 @@ static const struct attribute_group *vfio_ap_mdev_attr_groups[] = { > NULL > }; > > -/** > - * vfio_ap_mdev_set_kvm > - * > - * @matrix_mdev: a mediated matrix device > - * @kvm: reference to KVM instance > - * > - * Verifies no other mediated matrix device has @kvm and sets a reference to > - * it in @matrix_mdev->kvm. > - * > - * Return 0 if no other mediated matrix device has a reference to @kvm; > - * otherwise, returns an -EPERM. > - */ > -static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev *matrix_mdev, > - struct kvm *kvm) > -{ > - struct ap_matrix_mdev *m; > - > - mutex_lock(&matrix_dev->lock); > - > - list_for_each_entry(m, &matrix_dev->mdev_list, node) { > - if ((m != matrix_mdev) && (m->kvm == kvm)) { > - mutex_unlock(&matrix_dev->lock); > - return -EPERM; > - } > - } > - > - matrix_mdev->kvm = kvm; > - mutex_unlock(&matrix_dev->lock); > - > - return 0; > -} > - > static int vfio_ap_mdev_group_notifier(struct notifier_block *nb, > unsigned long action, void *data) > { > - int ret; > struct ap_matrix_mdev *matrix_mdev; > > if (action != VFIO_GROUP_NOTIFY_SET_KVM) > return NOTIFY_OK; > > matrix_mdev = container_of(nb, struct ap_matrix_mdev, group_notifier); > - > - if (!data) { > - matrix_mdev->kvm = NULL; > - return NOTIFY_OK; > - } > - > - ret = vfio_ap_mdev_set_kvm(matrix_mdev, data); > - if (ret) > - return NOTIFY_DONE; > - > - /* If there is no CRYCB pointer, then we can't copy the masks */ > - if (!matrix_mdev->kvm->arch.crypto.crycbd) > - return NOTIFY_DONE; > - > - kvm_arch_crypto_set_masks(matrix_mdev->kvm, matrix_mdev->matrix.apm, > - matrix_mdev->matrix.aqm, > - matrix_mdev->matrix.adm); > + matrix_mdev->kvm = data; > > return NOTIFY_OK; > } > > -static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev) > +static int vfio_ap_mdev_reset_queues(struct ap_matrix_mdev *matrix_mdev) > { > int ret; > int rc = 0; > - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev); > struct vfio_ap_queue *q; > > list_for_each_entry(q, &matrix_mdev->qlist, list) { > @@ -871,41 +821,106 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev) > return rc; > } > > +/** > + * vfio_ap_mdev_set_kvm > + * > + * @matrix_mdev: a mediated matrix device > + * > + * - Verifies that the hook is free and install the PQAP hook > + * - Copy the matrix masks inside the CRYCB > + * - Increment the KVM rerference count > + * > + * Return 0 if no other mediated matrix device has a reference to @kvm; > + * otherwise, returns an -EPERM. > + */ > +static int vfio_ap_mdev_set_kvm(struct ap_matrix_mdev *matrix_mdev) > +{ > + if (matrix_mdev->kvm->arch.crypto.pqap_hook) > + return -EPERM; How would this happen; in other words, why are we checking this? > + matrix_mdev->kvm->arch.crypto.pqap_hook = &matrix_mdev->pqap_hook; > + > + kvm_arch_crypto_set_masks(matrix_mdev->kvm, matrix_mdev->matrix.apm, > + matrix_mdev->matrix.aqm, > + matrix_mdev->matrix.adm); > + > + kvm_get_kvm(matrix_mdev->kvm); > + return 0; > +} > + > +/** > + * vfio_ap_mdev_unset_kvm > + * > + * @matrix_mdev: a mediated matrix device > + * > + * - Clears the matrix masks inside the CRYCB > + * - Reset the queues before to clear the hook in case IRQ happen during > + * reset. > + * - Clears the hook > + * - Decrement the KVM rerference count > + */ > +static int vfio_ap_mdev_unset_kvm(struct ap_matrix_mdev *matrix_mdev) > +{ > + struct kvm *kvm = matrix_mdev->kvm; > + > + kvm_arch_crypto_clear_masks(matrix_mdev->kvm); > + vfio_ap_mdev_reset_queues(matrix_mdev); > + matrix_mdev->kvm->arch.crypto.pqap_hook = NULL; > + matrix_mdev->kvm = NULL; > + kvm_put_kvm(kvm); > + return 0; > +} > + > 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; > > + mutex_lock(&matrix_dev->lock); > > - if (!try_module_get(THIS_MODULE)) > - return -ENODEV; > + if (!try_module_get(THIS_MODULE)) { > + ret = -ENODEV; > + goto unlock; > + } > > 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) { > - module_put(THIS_MODULE); > - return ret; > + if (ret) > + goto put_unlock; > + > + /* We do not support opening the mediated device without KVM */ > + if (!matrix_mdev->kvm) { > + ret = -ENOENT; > + goto free_notifier; > } > > - return 0; > + ret = vfio_ap_mdev_set_kvm(matrix_mdev); > + if (!ret) > + goto unlock; > + > +free_notifier: > + vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, > + &matrix_mdev->group_notifier); > +put_unlock: > + module_put(THIS_MODULE); > +unlock: > + mutex_unlock(&matrix_dev->lock); > + return ret; > } > > static void vfio_ap_mdev_release(struct mdev_device *mdev) > { > struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev); > > - if (matrix_mdev->kvm) > - kvm_arch_crypto_clear_masks(matrix_mdev->kvm); > - > - matrix_mdev->kvm = NULL; > - vfio_ap_mdev_reset_queues(mdev); > + mutex_lock(&matrix_dev->lock); > + vfio_ap_mdev_unset_kvm(matrix_mdev); > vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, > &matrix_mdev->group_notifier); > module_put(THIS_MODULE); > + mutex_unlock(&matrix_dev->lock); > } > > static int vfio_ap_mdev_get_device_info(unsigned long arg) > @@ -939,7 +954,7 @@ static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev, > break; > case VFIO_DEVICE_RESET: > mutex_lock(&matrix_dev->lock); > - ret = vfio_ap_mdev_reset_queues(mdev); > + ret = vfio_ap_mdev_reset_queues(mdev_get_drvdata(mdev)); > mutex_unlock(&matrix_dev->lock); > break; > default: >