From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre Morel Subject: Re: [PATCH v6 3/7] s390: ap: setup relation betwen KVM and mediated device Date: Thu, 28 Mar 2019 17:27:41 +0100 Message-ID: <3cd496d0-3eec-78e8-9ea5-4d62fe0cff1c@linux.ibm.com> References: <1553265828-27823-1-git-send-email-pmorel@linux.ibm.com> <1553265828-27823-4-git-send-email-pmorel@linux.ibm.com> <1ea236d1-ca0b-03c0-3699-0c0deb435785@linux.ibm.com> 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: <1ea236d1-ca0b-03c0-3699-0c0deb435785@linux.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: Tony Krowiak , borntraeger@de.ibm.com 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 List-ID: On 28/03/2019 17:12, Tony Krowiak wrote: > 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? I check this to verify that no other AP mediated device is already in use by this VM. Regards, Pierre -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany