Messages in this thread | | | Subject | Re: [PATCH v6 3/7] s390: ap: setup relation betwen KVM and mediated device | From | Tony Krowiak <> | Date | Thu, 28 Mar 2019 13:25:35 -0400 |
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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 <pmorel@linux.ibm.com> >>> --- >>> 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 > > >
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