Messages in this thread | | | Subject | Re: [PATCH v2 6/7] s390: vfio-ap: handle bind and unbind of AP queue device | From | Pierre Morel <> | Date | Mon, 6 May 2019 12:55:49 +0200 |
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On 03/05/2019 23:14, Tony Krowiak wrote: > There is nothing preventing a root user from inadvertently unbinding an > AP queue device that is in use by a guest from the vfio_ap device driver > and binding it to a zcrypt driver. This can result in a queue being > accessible from both the host and a guest. > > This patch introduces safeguards that prevent sharing of an AP queue > between the host when a queue device is unbound from the vfio_ap device > driver. In addition, this patch restores guest access to AP queue devices > bound to the vfio_ap driver if the queue's APQN is assigned to an mdev > device in use by a guest. > > Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com> > --- > drivers/s390/crypto/vfio_ap_drv.c | 12 +++- > drivers/s390/crypto/vfio_ap_ops.c | 100 +++++++++++++++++++++++++++++++++- > drivers/s390/crypto/vfio_ap_private.h | 2 + > 3 files changed, 111 insertions(+), 3 deletions(-) > > diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c > index e9824c35c34f..c215978daf39 100644 > --- a/drivers/s390/crypto/vfio_ap_drv.c > +++ b/drivers/s390/crypto/vfio_ap_drv.c > @@ -42,12 +42,22 @@ MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids); > > static int vfio_ap_queue_dev_probe(struct ap_device *apdev) > { > + struct ap_queue *queue = to_ap_queue(&apdev->device); > + > + mutex_lock(&matrix_dev->lock); > + vfio_ap_mdev_probe_queue(queue); > + mutex_unlock(&matrix_dev->lock); > + > return 0; > } > > static void vfio_ap_queue_dev_remove(struct ap_device *apdev) > { > - /* Nothing to do yet */ > + struct ap_queue *queue = to_ap_queue(&apdev->device); > + > + mutex_lock(&matrix_dev->lock); > + vfio_ap_mdev_remove_queue(queue); > + mutex_unlock(&matrix_dev->lock); > } > > static void vfio_ap_matrix_dev_release(struct device *dev) > diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c > index ede45184eb67..40324951bd37 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -226,8 +226,6 @@ static struct device *vfio_ap_get_queue_dev(unsigned long apid, > &apqn, match_apqn); > } > > - > - > static int vfio_ap_mdev_validate_masks(unsigned long *apm, unsigned long *aqm) > { > int ret; > @@ -259,6 +257,27 @@ static bool vfio_ap_queues_on_drv(unsigned long *apm, unsigned long *aqm) > return true; > } > > +static bool vfio_ap_card_on_drv(struct ap_queue *queue, unsigned long *aqm) > +{ > + unsigned long apid, apqi; > + struct device *dev; > + > + apid = AP_QID_CARD(queue->qid); > + > + for_each_set_bit_inv(apqi, aqm, AP_DOMAINS) { > + if (queue->qid == AP_MKQID(apid, apqi)) > + continue; > + > + dev = vfio_ap_get_queue_dev(apid, apqi); > + if (!dev) > + return false; > + > + put_device(dev); > + } > + > + return true; > +} > + > /** > * assign_adapter_store > * > @@ -1017,3 +1036,80 @@ void vfio_ap_mdev_unregister(void) > { > mdev_unregister_device(&matrix_dev->device); > } > + > +static struct ap_matrix_mdev *vfio_ap_mdev_find_matrix_mdev(unsigned long apid, > + unsigned long apqi) > +{ > + struct ap_matrix_mdev *matrix_mdev; > + > + list_for_each_entry(matrix_mdev, &matrix_dev->mdev_list, node) { > + if (test_bit_inv(apid, matrix_mdev->matrix.apm) && > + test_bit_inv(apqi, matrix_mdev->matrix.aqm)) > + return matrix_mdev; > + } > + > + return NULL; > +} > + > +void vfio_ap_mdev_probe_queue(struct ap_queue *queue) > +{ > + struct ap_matrix_mdev *matrix_mdev; > + unsigned long *shadow_apm, *shadow_aqm; > + unsigned long apid = AP_QID_CARD(queue->qid); > + unsigned long apqi = AP_QID_QUEUE(queue->qid); > + > + /* > + * Find the mdev device to which the APQN of the queue device being > + * probed is assigned > + */ > + matrix_mdev = vfio_ap_mdev_find_matrix_mdev(apid, apqi); > + > + /* Check whether we found an mdev device and it is in use by a guest */ > + if (matrix_mdev && matrix_mdev->kvm) { > + shadow_apm = matrix_mdev->shadow_crycb->apm; > + shadow_aqm = matrix_mdev->shadow_crycb->aqm; > + /* > + * If the guest already has access to the adapter card > + * referenced by APID or does not have access to the queues > + * referenced by APQI, there is nothing to do here. > + */ > + if (test_bit_inv(apid, shadow_apm) || > + !test_bit_inv(apqi, shadow_aqm)) > + return; > + > + /* > + * If each APQN with the APID of the queue being probed and an > + * APQI in the shadow CRYCB references a queue device that is > + * bound to the vfio_ap driver, then plug the adapter into the > + * guest. > + */ > + if (vfio_ap_card_on_drv(queue, shadow_aqm)) { > + set_bit_inv(apid, shadow_apm); > + vfio_ap_mdev_update_crycb(matrix_mdev); > + } > + } > +} > + > +void vfio_ap_mdev_remove_queue(struct ap_queue *queue) > +{ > + struct ap_matrix_mdev *matrix_mdev; > + unsigned long apid = AP_QID_CARD(queue->qid); > + unsigned long apqi = AP_QID_QUEUE(queue->qid); > + > + matrix_mdev = vfio_ap_mdev_find_matrix_mdev(apid, apqi); > + > + /* > + * If the queue is assigned to the mdev device and the mdev device > + * is in use by a guest, unplug the adapter referred to by the APID > + * of the APQN of the queue being removed. > + */ > + if (matrix_mdev && matrix_mdev->kvm) { > + if (!test_bit_inv(apid, matrix_mdev->shadow_crycb->apm)) > + return; > + > + clear_bit_inv(apid, matrix_mdev->shadow_crycb->apm); > + vfio_ap_mdev_update_crycb(matrix_mdev); > + } > + > + vfio_ap_mdev_reset_queue(apid, apqi); > +} > diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h > index e8457aa61976..6b1f7df5b979 100644 > --- a/drivers/s390/crypto/vfio_ap_private.h > +++ b/drivers/s390/crypto/vfio_ap_private.h > @@ -87,5 +87,7 @@ struct ap_matrix_mdev { > > extern int vfio_ap_mdev_register(void); > extern void vfio_ap_mdev_unregister(void); > +void vfio_ap_mdev_remove_queue(struct ap_queue *queue); > +void vfio_ap_mdev_probe_queue(struct ap_queue *queue); > > #endif /* _VFIO_AP_PRIVATE_H_ */ >
AFAIU the apmask/aqmask of the AP_BUS are replacing bind/unbind for the admin. Don't they? Then why not suppress bind/unbind for ap_queues?
Otherwise, it seems to me to handle correctly the disappearance of a card, which is the only thing that can happen from out of the firmware queue change requires configuration change and re-IPL.
Even still need testing, LGTM
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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