Messages in this thread | | | Subject | Re: [PATCH v2 7/8] s390: vfio-ap: handle bind and unbind of AP queue device | From | Pierre Morel <> | Date | Tue, 23 Apr 2019 15:08:36 +0200 |
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On 20/04/2019 23:49, Tony Krowiak wrote: > There is an implied guarantee that when an AP queue device is bound to a > device driver, that driver will have exclusive control over the device. > When an AP queue device is unbound from the vfio_ap driver while the > queue is in use by a guest and subsquently bound to a zcrypt driver, the > guarantee that the zcrypt driver has exclusive control of the queue > device will be violated. Likewise, when an AP queue device is bound to > the vfio_ap device driver and its APQN is assigned to an mdev device in > use by a guest, the expectation is that the guest will have access to > the queue. > > The purpose of this patch is to ensure three things: > > 1. When an AP queue device in use by a guest is unbound, the guest shall > no longer access the queue. Due to the limitations of the > architecture, access to a single queue can not be denied to a guest, > so access to the AP card to which the queue is connected will be > denied to the guest. > > 2. When an AP queue device with an APQN assigned to an mdev device is > bound to the vfio_ap driver while the mdev device is in use by a guest, > the guest shall be granted access to the queue. > > 3. When a guest is started, each APQN assigned to the guest's mdev device > must be owned by the vfio_ap driver. > > Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com> > --- > drivers/s390/crypto/vfio_ap_drv.c | 16 ++++++- > drivers/s390/crypto/vfio_ap_ops.c | 82 ++++++++++++++++++++++++++++++++++- > drivers/s390/crypto/vfio_ap_private.h | 2 + > 3 files changed, 97 insertions(+), 3 deletions(-) > > diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c > index e9824c35c34f..0f5dafddf5b1 100644 > --- a/drivers/s390/crypto/vfio_ap_drv.c > +++ b/drivers/s390/crypto/vfio_ap_drv.c > @@ -42,12 +42,26 @@ MODULE_DEVICE_TABLE(vfio_ap, ap_queue_ids); > > static int vfio_ap_queue_dev_probe(struct ap_device *apdev) > { > + struct ap_queue *apq = to_ap_queue(&apdev->device); > + unsigned long apid = AP_QID_CARD(apq->qid); > + unsigned long apqi = AP_QID_QUEUE(apq->qid); > + > + mutex_lock(&matrix_dev->lock); > + vfio_ap_mdev_probe_queue(apid, apqi); > + 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 *apq = to_ap_queue(&apdev->device); > + unsigned long apid = AP_QID_CARD(apq->qid); > + unsigned long apqi = AP_QID_QUEUE(apq->qid); > + > + mutex_lock(&matrix_dev->lock); > + vfio_ap_mdev_remove_queue(apid, apqi); > + 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 31ce30ee784d..3f9506516545 100644 > --- a/drivers/s390/crypto/vfio_ap_ops.c > +++ b/drivers/s390/crypto/vfio_ap_ops.c > @@ -763,8 +763,8 @@ static void vfio_ap_mdev_wait_for_qempty(unsigned long apid, unsigned long apqi) > msleep(20); > break; > default: > - pr_warn("%s: tapq err %02x: 0x%04x may not be empty\n", > - __func__, status.response_code, q->apqn); > + pr_warn("%s: tapq err %02x: %02lx%04lx may not be empty\n", > + __func__, status.response_code, apid, apqi); > return; > } > } while (--retry); > @@ -823,6 +823,14 @@ static int vfio_ap_mdev_reset_queues(struct mdev_device *mdev) > > static int vfio_ap_mdev_create_shadow_crycb(struct ap_matrix_mdev *matrix_mdev) > { > + /* > + * If an AP resource is not owned by the vfio_ap driver - e.g., it was > + * unbound from the driver while still assigned to the mdev device > + */ > + if (ap_apqn_in_matrix_owned_by_def_drv(matrix_mdev->matrix.apm, > + matrix_mdev->matrix.aqm)) > + return -EADDRNOTAVAIL; > + > matrix_mdev->shadow_crycb = kzalloc(sizeof(*matrix_mdev->shadow_crycb), > GFP_KERNEL); > if (!matrix_mdev->shadow_crycb) > @@ -847,6 +855,18 @@ static int vfio_ap_mdev_open(struct mdev_device *mdev) > if (!try_module_get(THIS_MODULE)) > return -ENODEV; > > + ret = ap_apqn_in_matrix_owned_by_def_drv(matrix_mdev->matrix.apm, > + matrix_mdev->matrix.aqm); > + > + /* > + * If any APQN is owned by a default driver, it can not be used by the > + * guest. This can happen if a queue is unbound from the vfio_ap > + * driver but not unassigned from the mdev device. > + */ > + ret = (ret == 1) ? -EADDRNOTAVAIL : ret; > + if (ret) > + return ret; > + > matrix_mdev->group_notifier.notifier_call = vfio_ap_mdev_group_notifier; > events = VFIO_GROUP_NOTIFY_SET_KVM; > > @@ -938,3 +958,61 @@ 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_remove_queue(unsigned long apid, unsigned long apqi) > +{ > + struct ap_matrix_mdev *matrix_mdev; > + > + 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 > + */ > + if (matrix_mdev && matrix_mdev->kvm) { > + /* > + * Unplug the adapter from the guest but don't unassign it > + * from the mdev device > + */ > + clear_bit_inv(apid, matrix_mdev->shadow_crycb->apm); > + vfio_ap_mdev_update_crycb(matrix_mdev); > + } > + > + vfio_ap_mdev_reset_queue(apid, apqi); > +} > + > +void vfio_ap_mdev_probe_queue(unsigned long apid, unsigned long apqi) > +{ > + struct ap_matrix_mdev *matrix_mdev; > + > + 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 > + */ > + if (matrix_mdev && matrix_mdev->kvm) { > + /* Plug the adapter into the guest */ > + set_bit_inv(apid, matrix_mdev->shadow_crycb->apm); > + > + /* Make sure the queue is also plugged in to the guest */ > + if (!test_bit_inv(apqi, matrix_mdev->shadow_crycb->aqm)) > + set_bit_inv(apqi, matrix_mdev->shadow_crycb->aqm);
Why are you testing the domain before setting it and not the adapter?
Eventually you do not need to test at all or if, then both.
NIT
> + > + vfio_ap_mdev_update_crycb(matrix_mdev); > + } > +} > diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h > index e8457aa61976..00eaae3b853f 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(unsigned long apid, unsigned long apqi); > +void vfio_ap_mdev_probe_queue(unsigned long apid, unsigned long apqi); > > #endif /* _VFIO_AP_PRIVATE_H_ */ >
-- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany
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