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 13:25:35 -0400 Message-ID: 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> <3cd496d0-3eec-78e8-9ea5-4d62fe0cff1c@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: <3cd496d0-3eec-78e8-9ea5-4d62fe0cff1c@linux.ibm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: pmorel@linux.ibm.com, 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 3/28/19 12:27 PM, Pierre Morel wrote: > 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. Maybe you should insert a comment to that effect. > > Regards, > Pierre > > >