Messages in this thread | | | Subject | Re: [PATCH v2 2/7] s390: vfio-ap: maintain a shadow of the guest's CRYCB | From | Tony Krowiak <> | Date | Mon, 6 May 2019 15:53:09 -0400 |
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On 5/6/19 2:49 AM, Pierre Morel wrote: > On 03/05/2019 23:14, Tony Krowiak wrote: >> This patch introduces a shadow of the CRYCB being used by a guest. This >> will enable to more effectively manage dynamic changes to the AP >> resources installed on the host that may be assigned to an mdev device >> and being used by a guest. For example: >> >> * AP adapter cards can be dynamically added to and removed from the AP >> configuration via the SE or an SCLP command. >> >> * AP resources that disappear and reappear due to hardware malfunctions. >> >> * AP queues bound to and unbound from the vfio_ap device driver by a >> root user. >> >> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com> >> --- >> drivers/s390/crypto/vfio_ap_ops.c | 91 >> ++++++++++++++++++++++++++++++++--- >> drivers/s390/crypto/vfio_ap_private.h | 2 + >> 2 files changed, 87 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/s390/crypto/vfio_ap_ops.c >> b/drivers/s390/crypto/vfio_ap_ops.c >> index b88a2a2ba075..44a04b4aa9ae 100644 >> --- a/drivers/s390/crypto/vfio_ap_ops.c >> +++ b/drivers/s390/crypto/vfio_ap_ops.c >> @@ -297,6 +297,45 @@ static void vfio_ap_mdev_wait_for_qempty(unsigned >> long apid, unsigned long apqi) >> } while (--retry); >> } >> +/* >> + * vfio_ap_mdev_update_crycb >> + * >> + * @matrix_mdev: the mediated matrix device >> + * >> + * Updates the AP matrix in the guest's CRYCB from it's shadow masks. >> + * >> + * Returns zero if the guest's CRYCB is successfully updated; otherwise, >> + * returns -ENODEV if a guest is not running or does not have a CRYCB. >> + */ >> +static int vfio_ap_mdev_update_crycb(struct ap_matrix_mdev *matrix_mdev) >> +{ >> + if (!matrix_mdev->kvm || !matrix_mdev->kvm->arch.crypto.crycbd) >> + return -ENODEV; >> + >> + kvm_arch_crypto_set_masks(matrix_mdev->kvm, >> + matrix_mdev->shadow_crycb->apm, >> + matrix_mdev->shadow_crycb->aqm, >> + matrix_mdev->shadow_crycb->adm); >> + >> + return 0; >> +} >> + >> +static int match_apqn(struct device *dev, void *data) >> +{ >> + struct ap_queue *apq = to_ap_queue(dev); >> + >> + return (apq->qid == *(unsigned long *)(data)) ? 1 : 0; >> +} >> + >> +static struct device *vfio_ap_get_queue_dev(unsigned long apid, >> + unsigned long apqi) >> +{ >> + unsigned long apqn = AP_MKQID(apid, apqi); >> + >> + return driver_find_device(&matrix_dev->vfio_ap_drv->driver, NULL, >> + &apqn, match_apqn); >> +} >> + >> /** >> * assign_adapter_store >> * >> @@ -805,14 +844,9 @@ static int vfio_ap_mdev_group_notifier(struct >> notifier_block *nb, >> 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) >> + if (vfio_ap_mdev_update_crycb(matrix_mdev)) >> return NOTIFY_DONE; >> - kvm_arch_crypto_set_masks(matrix_mdev->kvm, matrix_mdev->matrix.apm, >> - matrix_mdev->matrix.aqm, >> - matrix_mdev->matrix.adm); >> - >> return NOTIFY_OK; >> } >> @@ -867,12 +901,55 @@ static int vfio_ap_mdev_reset_queues(struct >> mdev_device *mdev) >> return rc; >> } >> +static int vfio_ap_mdev_create_shadow_crycb(struct ap_matrix_mdev >> *matrix_mdev) >> +{ >> + unsigned long apid, apqi, domid; >> + struct device *dev; >> + >> + matrix_mdev->shadow_crycb = >> kzalloc(sizeof(*matrix_mdev->shadow_crycb), >> + GFP_KERNEL); >> + if (!matrix_mdev->shadow_crycb) >> + return -ENOMEM; >> + >> + vfio_ap_matrix_init(&matrix_dev->info, matrix_mdev->shadow_crycb); >> + >> + /* >> + * Examine each APQN assigned to the mdev device. Set the APID >> and APQI >> + * in the shadow CRYCB if and only if the queue device identified by >> + * the APQN is in the configuration. >> + */ >> + for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, >> + matrix_mdev->matrix.apm_max + 1) { >> + for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, >> + matrix_mdev->matrix.aqm_max + 1) { >> + dev = vfio_ap_get_queue_dev(apid, apqi); >> + if (dev) { >> + set_bit_inv(apid, >> + matrix_mdev->shadow_crycb->apm); >> + set_bit_inv(apqi, >> + matrix_mdev->shadow_crycb->aqm); >> + put_device(dev); >> + } > > I think that if we do not find a device here we have a problem. > Don't we?
Other than the fact that the guest will not have any AP devices, what would be the problem? What would you suggest?
> > >> + } >> + } >> + >> + /* Set all control domains assigned to the mdev in the shadow >> CRYCB */ >> + for_each_set_bit_inv(domid, matrix_mdev->matrix.adm, >> + matrix_mdev->matrix.adm_max + 1) >> + set_bit_inv(domid, matrix_mdev->shadow_crycb->adm); >> + >> + 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; >> + ret = vfio_ap_mdev_create_shadow_crycb(matrix_mdev); >> + if (ret) >> + return ret; >> if (!try_module_get(THIS_MODULE)) >> return -ENODEV; >> @@ -902,6 +979,8 @@ static void vfio_ap_mdev_release(struct >> mdev_device *mdev) >> &matrix_mdev->group_notifier); >> matrix_mdev->kvm = NULL; >> module_put(THIS_MODULE); >> + kfree(matrix_mdev->shadow_crycb); >> + matrix_mdev->shadow_crycb = NULL; >> } >> static int vfio_ap_mdev_get_device_info(unsigned long arg) >> diff --git a/drivers/s390/crypto/vfio_ap_private.h >> b/drivers/s390/crypto/vfio_ap_private.h >> index 76b7f98e47e9..e8457aa61976 100644 >> --- a/drivers/s390/crypto/vfio_ap_private.h >> +++ b/drivers/s390/crypto/vfio_ap_private.h >> @@ -72,6 +72,7 @@ struct ap_matrix { >> * @list: allows the ap_matrix_mdev struct to be added to a list >> * @matrix: the adapters, usage domains and control domains >> assigned to the >> * mediated matrix device. >> + * @shadow_crycb: a shadow copy of the crycb in use by a guest >> * @group_notifier: notifier block used for specifying callback >> function for >> * handling the VFIO_GROUP_NOTIFY_SET_KVM event >> * @kvm: the struct holding guest's state >> @@ -79,6 +80,7 @@ struct ap_matrix { >> struct ap_matrix_mdev { >> struct list_head node; >> struct ap_matrix matrix; >> + struct ap_matrix *shadow_crycb; >> struct notifier_block group_notifier; >> struct kvm *kvm; >> }; >> > >
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