From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v5 4/7] s390: ap: setup relation betwen KVM and mediated device Date: Tue, 19 Mar 2019 10:38:42 +0100 Message-ID: <7c199329-0e82-ff61-46b7-78237a0f01ce@linux.ibm.com> References: <1552493104-30510-1-git-send-email-pmorel@linux.ibm.com> <1552493104-30510-5-git-send-email-pmorel@linux.ibm.com> <20190315191557.6c8d7668@oc2783563651> Reply-To: pmorel@linux.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190315191557.6c8d7668@oc2783563651> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Halil Pasic Cc: borntraeger@de.ibm.com, 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, akrowiak@linux.ibm.com, david@redhat.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, freude@linux.ibm.com, mimu@linux.ibm.com List-ID: On 15/03/2019 19:15, Halil Pasic wrote: > On Wed, 13 Mar 2019 17:05:01 +0100 > Pierre Morel wrote: > >> When the mediated device is open we setup the relation with KVM unset it >> when the mediated device is released. >> >> We ensure KVM is present on opening of the mediated device. >> >> We ensure that KVM survives the mediated device, and establish a direct > > survives? what alternative do you prefer? > >> link from KVM to the mediated device to simplify the relationship. >> >> Signed-off-by: Pierre Morel >> --- ...snip... >> 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; >> } >> @@ -888,6 +873,12 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev) >> if (ret) >> goto err_group; >> >> + /* We do not support opening the mediated device without KVM */ >> + if (!matrix_mdev->kvm) { >> + ret = -ENODEV; >> + goto err_group; >> + } >> + >> matrix_mdev->iommu_notifier.notifier_call = vfio_ap_mdev_iommu_notifier; >> events = VFIO_IOMMU_NOTIFY_DMA_UNMAP; >> >> @@ -896,8 +887,15 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev) >> if (ret) >> goto err_iommu; >> >> + ret = vfio_ap_mdev_set_kvm(matrix_mdev); > > At this point the matrix_mdev->kvm ain't guaranteed to be valid IMHO. Or > am I wrong? If I'm right kvm_get_kvm(matrix_mdev->kvm) could be too late. What about the if (!matrix_mdev->kvm) 10 lines above ? > >> + if (ret) >> + goto err_kvm; >> + >> return 0; >> >> +err_kvm: >> + vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY, >> + &matrix_mdev->iommu_notifier); >> err_iommu: >> vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY, >> &matrix_mdev->group_notifier); >> @@ -906,19 +904,33 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev) >> return ret; >> } >> >> -static void vfio_ap_mdev_release(struct mdev_device *mdev) >> +static int vfio_ap_mdev_unset_kvm(struct ap_matrix_mdev *matrix_mdev) >> { >> - struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev); >> + struct kvm *kvm = matrix_mdev->kvm; >> >> if (matrix_mdev->kvm) >> kvm_arch_crypto_clear_masks(matrix_mdev->kvm); > > This still conditional? Yes, nothing to clear if there is no KVM. > >> - >> + vfio_ap_mdev_reset_queues(matrix_mdev->mdev); > > I guess your intention was to move vfio_ap_mdev_reset_queues() > here from vfio_ap_mdev_release(), but you still have a > vfio_ap_mdev_reset_queues() call in vfio_ap_mdev_release(). > >> + matrix_mdev->kvm->arch.crypto.pqap_hook = NULL; >> matrix_mdev->kvm = NULL; >> + >> + kvm_put_kvm(kvm); >> + return 0; >> +} >> + >> +static void vfio_ap_mdev_release(struct mdev_device *mdev) >> +{ >> + struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev); >> + >> + mutex_lock(&matrix_dev->lock); >> + >> vfio_ap_mdev_reset_queues(mdev); right, this one will go away. Thanks for reviewing. Regards, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany